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Speaker 1: Welcome to Stuff to Blow Your Mind from how Stuff

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Speaker 1: Works dot com. Hey, what can the stuff to blow

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Speaker 1: your mind? My name is Robert lamp and my name

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Speaker 1: is Joe mcformack, and we're gonna get right to it

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Speaker 1: today because we're going to talk about sexual cannibalism, right

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Speaker 1: And I do want to just throw out here right

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Speaker 1: at the top, this is not going to concern human

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Speaker 1: cannibalism at all. I know that in the past when

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Speaker 1: we've covered cannibalistic topics, some listeners have actually skipped the

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Speaker 1: episode thinking that there might be human cannibals. And I'm

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Speaker 1: just gonna let you know, if you've made it this far,

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Speaker 1: no human cannibals, will cannibals will occur in this episode.

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Speaker 1: Is that some people's big thing? It's like, Oh, you're

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Speaker 1: gonna talk about cannibalism. I can't go on. Well, you know,

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Speaker 1: I mean some listeners, some of our listeners really want

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Speaker 1: the dark content. And that's why and and and we're

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Speaker 1: certainly happy to go there and as well as strip

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Speaker 1: away some of the the taboo and the mystery surrounding

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Speaker 1: those dark topics. But I know that not everyone wants

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Speaker 1: to go down that path with us. So I just

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Speaker 1: want to let everyone know we're not going down the

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Speaker 1: human cannibal path. Okay, So we are going to be

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Speaker 1: talking about animal sexual cannibalism. And this is a topic

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Speaker 1: that's been touched on on the show before. I Know

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Speaker 1: You and Julie in the Past is an episode about

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Speaker 1: cannibalism in the animal world, but today we wanted to

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Speaker 1: focus specifically on sexual cannibalism because of all of the

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Speaker 1: interesting evolutionary interplay here. Yea, the sort of trade off

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Speaker 1: of costs and benefits that would lead a species to

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Speaker 1: at some rate fairly often enough that people would notice

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Speaker 1: eat during sex, eat each other during sex or after sex. Yeah.

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Speaker 1: And it's the interesting thing about this topic is that,

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Speaker 1: on one hand, it is very simplistic, and I'll get

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Speaker 1: into the simplistic argument shortly, but then it's also not

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Speaker 1: as cut and dry as you might think. It's an

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Speaker 1: area where they are multiple theories as to as do

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Speaker 1: how this evolved and exactly how it's working, and some

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Speaker 1: of those are actually conflicting theories as well. So it's, uh,

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Speaker 1: it's a subject with a lot of meat on it,

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Speaker 1: a lot of sexy meat on it. Okay, so what's

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Speaker 1: the basic gist of why sexual cannibalism happens. This might

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Speaker 1: be kind of obvious, but we should get it on

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Speaker 1: the table so that we have a place to start.

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Speaker 1: So let's say you have two spiders and they size

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Speaker 1: each other up, and they say it's time to mate.

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Speaker 1: You know, we'll pass our genes on. But some way

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Speaker 1: through the mating procedure, the female sort of grabs hold

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Speaker 1: of the mail and sinks her fangs into him and

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Speaker 1: drains all of his delicious juices. Why did that happen?

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Speaker 1: And that's and that is the big question, right, why

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Speaker 1: does this evolve and why does this occur? Certainly not

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Speaker 1: in every species, it's actually a very rare occurrence in

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Speaker 1: the natural world. But where it does occur, uh, we

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Speaker 1: can't help it. Study it well. Actually, we should start

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Speaker 1: with the simple side. It's clear why this happens from

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Speaker 1: the female side. A lot of the question is why

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Speaker 1: the male would participate in this, right, But but why

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Speaker 1: does the female eat the male? Well? For energy, of course,

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Speaker 1: I mean that. I mean that basically comes down to

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Speaker 1: stripping away the human complexity surrounding cannibalism in general, because ultimately,

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Speaker 1: flesh is energy, flesh is food. Uh, flesh is life.

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Speaker 1: In addition, and so in addition to having all sorts

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Speaker 1: of cultural hangups about cannibalism, you know, we don't have

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Speaker 1: any problem wasting boatloads of food and energy, right, so

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Speaker 1: we kind of have to put that aside to think

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Speaker 1: of it. But yeah, in the in the natural world,

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Speaker 1: you see plenty of cases of just straight up cannibalism,

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Speaker 1: and it all comes down to a basic economy of

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Speaker 1: the energy. So a mother's young die, she might consume

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Speaker 1: those young because what are they now but empty vessels

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Speaker 1: made up of energy. Yeah, I think this is something

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Speaker 1: that's hard for us to understand because by and large,

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Speaker 1: if you are a human being listening to a podcast,

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Speaker 1: you probably are are lucky. You live a fortunate existence

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Speaker 1: where you have decent amounts of access to food. You're

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Speaker 1: you're probably not living constantly at the edge of starvation,

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Speaker 1: and animals are sort of built with the assumption that

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Speaker 1: they will be living constantly at the edge of starvation.

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Speaker 1: If you ever you ever noticed how if you have

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Speaker 1: a dog at home, if you're out walking the dog

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Speaker 1: and there's something that smells even remotely like it might

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Speaker 1: be food, the dog's going to try to put it

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Speaker 1: ahead and get in the mouth anyway, see what it takes.

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Speaker 1: And you and I would never think that way. I mean,

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Speaker 1: it's like smells like it could be food. Who knows

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Speaker 1: if it would hurt me? Better safe than sorry, I'm

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Speaker 1: just gonna eat it. Um. But in the animal kingdom,

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Speaker 1: out in the wild, that sort of strategy might make

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Speaker 1: a lot more sense, because if you are constantly at

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Speaker 1: risk of having your life extinguished or your competitive power

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Speaker 1: diminished by lack of access to energy resources, you'll take

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Speaker 1: anything you can get. Yeah, exactly. And you know, we

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Speaker 1: also have to think outside of the sort of human

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Speaker 1: male female scenario, right and get down to the basic

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Speaker 1: reality that I feel like is far more obvious when

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Speaker 1: you start looking at in the world of of insects

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Speaker 1: and arachnids and a few other species, and that is

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Speaker 1: that the females are the species and the male is

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Speaker 1: just this uh essentially, this mutation that's necessary to enable

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Speaker 1: genetic diversity through sexual reproduction. So he's he only has

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Speaker 1: this one purpose anyway, He's just this genetic material, heat

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Speaker 1: seeking missile and aid in reproduction. So why not eat him? Right?

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Speaker 1: His job is done, and there's there, that's it. Gets

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Speaker 1: to be more complex question, as we'll explore later. But

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Speaker 1: you know, it makes sense if you just look at

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Speaker 1: the pure math of the scenario. Yeah, and to get

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Speaker 1: even weirder, I mean, you might be able to say

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Speaker 1: that neither the male nor the female is really the

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Speaker 1: purpose of the speci sees the phenotype, the body, None

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Speaker 1: of that is the species. The species is a gene pool.

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Speaker 1: It's this abstract concept. It's really more of a movement

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Speaker 1: as opposed to a physical thing, because yeah, it's not

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Speaker 1: the little creatures that exist for especially in the insect world,

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Speaker 1: often very slim periods of time. It is that that

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Speaker 1: continued movement, genetic movement through time. Yeah, but but especially

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Speaker 1: the males. You might say, like if if there is

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Speaker 1: a sexual dimorphism in the species, a different in body,

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Speaker 1: a difference in body plans between male and female, and

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Speaker 1: it just you look at it and you say, wow,

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Speaker 1: it really looks like there's more going into the female.

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Speaker 1: She's bigger, she has more survival capacity. It really sometimes

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Speaker 1: can look to a human observer like, well, that's the

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Speaker 1: female is what the species is, and the male is

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Speaker 1: just sort of this thing that exists to mate. And yeah,

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Speaker 1: and I think you can make a pretty strong case

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Speaker 1: for that that the female is the primary member of

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Speaker 1: the species. Now already we're talking ing I think, in

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Speaker 1: sort of perhaps unscientific terms like what we're using anthropomorphization,

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Speaker 1: and we're using our our our sort of human judgment

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Speaker 1: of how things just seem to look to us, based

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Speaker 1: on the way we think about relationships between animals, probably

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Speaker 1: mostly based on the way we think about relationships between humans.

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Speaker 1: And this is sort of an inherent problem in studying

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Speaker 1: things like animal mating practices and reproduction and especially especially

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Speaker 1: sexual cannibalism. It we just can't help but infuse it

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Speaker 1: with all of the sort of social markers of how

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Speaker 1: we view relationships as humans. Yeah, and that's true of

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Speaker 1: not only consumers, readers, outsiders, true, not only of science

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Speaker 1: communicators like like ourselves, but also scientific researchers themselves. And

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Speaker 1: there was actually a paper on this, yeah, two thousand

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Speaker 1: ten paper, Sexual Stereotypes the Case of Sexual Cannibalism. This

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Speaker 1: was from the UK University of St Andrew schoo of Biology.

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Speaker 1: They looked at about they looked at a larger sample

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Speaker 1: and they had to to whittle it down. They end

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Speaker 1: up looking at around two ten relevant papers dealing with

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Speaker 1: sexual cannibalism, and they found that females were more likely

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Speaker 1: to be to be described using active words and males

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Speaker 1: with reactive words. And then a number of the words

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Speaker 1: used to describe cannibalistic females were highly loaded, suggesting a

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Speaker 1: negative stereotype of sexually aggressive females. Uh. And then the

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Speaker 1: males were more likely to be described as it's making

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Speaker 1: a sacrifice, while the females were just you know, voracious

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Speaker 1: widows um, that's funny. Voracious is a word I did

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Speaker 1: see pop up in the literature, in the scientific literature

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Speaker 1: on sexual cannibalism a lot. And and there are some

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Speaker 1: good points to be made about, you know, even though

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Speaker 1: this is sort of a tendency that's hard to overcome.

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Speaker 1: I know we're going to do it in this episode twenty.

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Speaker 1: We're gonna anthropomorphize. It's just how we talk about things,

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Speaker 1: how we talk about it's how we understand the topics,

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Speaker 1: how we conceptualize them in our head. There is a

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Speaker 1: good case to be made. I think that scientists do

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Speaker 1: their best to avoid this, and one simple reason is

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Speaker 1: that these kind of socially charged words are vague. Yeah,

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Speaker 1: you know, they're not they don't. They don't deal in

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Speaker 1: easily reproducible quantities. So if somebody wants to redo your

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Speaker 1: experiment somewhere else, can they tell what you mean by voracious?

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Speaker 1: I mean it seems like it makes more sense to

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Speaker 1: just talk about numerical conditions. So a spider that attacks

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Speaker 1: this percentage of prey within this you know, radius of

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Speaker 1: range is voracious. Yeah. And then I mean, just overall,

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Speaker 1: it's detrimental to view a species normalcy through the lembs

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Speaker 1: of our own species abnormality, because I mean, for instance,

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Speaker 1: we can study ducks without going holy crap. Can you

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Speaker 1: imagine if humans late eggs like a duck? So it's

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Speaker 1: a different creature, it's a different species. It is an

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Speaker 1: inhuman thing. And I guess anytime I study insects, I

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Speaker 1: always come back, maybe problematically to the line of Dr

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Speaker 1: Brundle in The Fly talking about uh insect politics and

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Speaker 1: how there are no insect politicians, um, which which I

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Speaker 1: think it's a great line, not only within the context

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Speaker 1: of that film, but also in terms of looking at

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Speaker 1: any of these scenarios where something through our lens, through

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Speaker 1: our lens of human normalcy, maybe just really horrific and monstrous,

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Speaker 1: and we want to cast this insect as a villain

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Speaker 1: and this as a poor, suffering martyr. But it is

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Speaker 1: an utterly inhuman system and there's no getting around that.

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Speaker 1: I'm sorry, I'm not listening to you because I'm imagining

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Speaker 1: the fly with a duck instead of a fly. So

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Speaker 1: Seth Brundle gets transformed into part duck and he's got

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Speaker 1: he's uh, he's got a bill. Well, you know how

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Speaker 1: the Duck and the Fly came out in the same year, Yeah,

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Speaker 1: oh wow, Yeah, that's a good year for film, the

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Speaker 1: year for film. In fact, we just had a how

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Speaker 1: Stuff Works Now article come out on that said, all

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Speaker 1: of your Howard the duck hate mail to blow the

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Speaker 1: mind dot com. But no. But moving on from how

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Speaker 1: weird it would be if humans were part duck, we

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Speaker 1: should look at the evolution of sexual cannibalism. And we're

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Speaker 1: going to talk about some specific cases later in this

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Speaker 1: episode of species that practice it and what we have

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Speaker 1: learned from them in recent studies. But where do we

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Speaker 1: typically see sexual cannibalism in the animal kingdom? Like, how

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Speaker 1: come you don't usually see a female cat eat a

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Speaker 1: male cat after sex? Well, I mean there's some biting

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Speaker 1: I think sometimes, but no, for the most part, we're

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Speaker 1: looking at insects and arachnids uh, spiders and scorpions being

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Speaker 1: the primary of research. There's some insects such as h

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Speaker 1: such as manted mantnanted species, and I believes there are

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Speaker 1: also some uh. Some evidences suggests that there are some

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Speaker 1: gastropod and copia pod cases. But in the for the

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Speaker 1: most part though, we're dealing with, especially with spiders and

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Speaker 1: scorpions and and and mantis, the species. We're dealing with

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Speaker 1: highly solitary predatory animals, which I think is key, especially

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Speaker 1: regarding some of the theories regarding sexual cannibalism. Right, So

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Speaker 1: if you want to keep in mind that they typically

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Speaker 1: aren't the most social animal rights that eat each other

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Speaker 1: after sex, and this might help inform our ideas about

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Speaker 1: how this evolved. Yeah, these are two anthropomorphizes. These are

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Speaker 1: lone killers. These are wanderers, right, that are just out

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Speaker 1: there on the highway eating what they need to eat

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Speaker 1: to survive. I say, even if you don't want to

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Speaker 1: infuse it with with human concepts of good and evil,

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Speaker 1: you could easily say that sexual cannibalism is a chaotic,

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Speaker 1: neutral trait. Yeah, yeah, I would think so so. But

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Speaker 1: but so, like we've said, it is rare in the

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Speaker 1: animal kingdom. You don't see it in most species. And

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Speaker 1: why is that? Well, on one, on one level, I

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Speaker 1: think we definitely have to again look to the solitary

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Speaker 1: predatory nature of these particular species. And then there's also

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Speaker 1: just cannibalism as a whole. If cannibalism is too essential

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Speaker 1: to the species, then you it eventually is going to

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Speaker 1: have an economically detrimental effect, right, So imagine your standard

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Speaker 1: sexual cannibalistic interaction. A female spider as a web. Male

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Speaker 1: spider approaches the web, climbs onto the web, mates with

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Speaker 1: the female, may or may not successfully impregnate her, and

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Speaker 1: the female eats the eats the male spider kills him,

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Speaker 1: drains all his fluids, gets energy from it. But the

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Speaker 1: male spider can mate no more. His days of passing

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Speaker 1: on his genes are now done. So this interaction works

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Speaker 1: out pretty well for the female spider. I mean, so

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Speaker 1: you can see why her genes would encourage such an interaction,

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Speaker 1: But the question is why would the male do that?

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Speaker 1: Why why does it uh genetically can I mean again,

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Speaker 1: we're using anthropomorphic terms like consent, But I would say,

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Speaker 1: why do its genes consent to this inner action where

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Speaker 1: it has a strong chance of being eaten? Indeed, that's

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Speaker 1: one of the big questions here, and one of the

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Speaker 1: questions that a number of these theories um of sexual

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Speaker 1: cannibism evolution explore. So at this point we should really

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Speaker 1: start talking about what those theories are and uh, and

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Speaker 1: then break into some of the examples that explore how

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Speaker 1: they work. Yeah. So there are several conflicting or competing

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Speaker 1: hypotheses about the evolution of sexual cannibalism, and we should

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Speaker 1: say that more than one can be true in different cases. Right,

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Speaker 1: There's some overlap here for sure. Yeah, But I think

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Speaker 1: one thing to keep in mind during these explanations is

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Speaker 1: that there are different ways that evolution can pay for

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Speaker 1: a trait. Let's say you have a trait that makes

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Speaker 1: you there's something about your brain that makes you really

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Speaker 1: likely to kick people in the face at the first

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Speaker 1: time you meet them. Um, there there are two ways

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Speaker 1: that could come through in your genes according to evolutionary theory,

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Speaker 1: and one one way is that the trade itself is

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Speaker 1: beneficial overall. People who kick people in the face first

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Speaker 1: time they meet just happened to have more kids than

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Speaker 1: people who don't, So it could be beneficial, or it

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Speaker 1: couldn't be. It could be an unintended side effect of

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Speaker 1: a very beneficial trait. So it could be that there's

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Speaker 1: actually not a good there's nothing good that comes from

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Speaker 1: kicking people in the face when you first meet them.

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Speaker 1: But you're really good at kicking people in the face

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Speaker 1: the rest of the time when exactly needed, So you're

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Speaker 1: much much better at defending yourself against predators. So you

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Speaker 1: just happened to be kicking crazy and and this is

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Speaker 1: just sort of and you're so good at defending yourself

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Speaker 1: for predators, this kicking genes survives even though it's not

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Speaker 1: particularly helpful in the case of kicking strangers in the

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Speaker 1: face when you first meet them. So the first of

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Speaker 1: these several theories we're gonna mention here is adaptive foraging.

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Speaker 1: So this one's pretty basic. Starving female mates the male

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Speaker 1: is there, she's hungry, she's gonna need energy. Why not

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Speaker 1: go ahead and eat him during either during the act

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Speaker 1: or immediately there after. Eating the male increases her chance

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Speaker 1: of survival, gives her a meal based power up uh

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Speaker 1: and as a as a as a sort of side

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Speaker 1: effect to her lover can't help produce any spawn that

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Speaker 1: end up rivaling her own for resources. But essentially it

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Speaker 1: comes down to I'm just I'm adapting to the what

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Speaker 1: food is available to me, and here is a meal

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Speaker 1: in front of me right now. Okay, So this is

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Speaker 1: sort of the the opportunism hypothesis. It's just saying that, like, look,

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Speaker 1: you know, the meal is worth it essentially right now.

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Speaker 1: Some of the critics argue that the males in many

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Speaker 1: of these cases, they actually make pretty poor meals. They're

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Speaker 1: not really going to make or break the female. But

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Speaker 1: then there are cases where they say that, hey, the

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Speaker 1: female is actually able to acquire crucial proteins or lipids

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Speaker 1: from the male that she eats that she might not

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Speaker 1: otherwise get from her standard predatory diet. Okay, So I'm

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Speaker 1: thinking that this is saying that the sexual cannibalism is

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Speaker 1: it's self an adaptation, It is itself a trait that

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Speaker 1: is encouraged because overall it's beneficial to the spider gene pool. Yeah,

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Speaker 1: not to the gene pool. I mean, it's I'm not

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Speaker 1: taking a species level evolution here. It would be beneficial

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Speaker 1: to the genes themselves in the animals that do it. Yeah,

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Speaker 1: the females who eat their male have just one little

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Speaker 1: power up over those who that do not. Yeah. And

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Speaker 1: the idea here is that this is very much a

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Speaker 1: kicking people in the face the first time you meet them. Right,

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Speaker 1: it's a good thing. Okay. But then there's another hypothesis

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Speaker 1: that is one I've read about some of the studies

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Speaker 1: I looked up here. It's the sort of I think

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Speaker 1: it's turned the aggressive spill over hypothesis. Uh. And this

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Speaker 1: is more that other idea we were talking about that

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Speaker 1: there are some traits that are very beneficial, but they

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Speaker 1: encourage side effects. So one trait, for example, might be

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Speaker 1: that a that a female is very aggressive in chasing

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Speaker 1: down prey. It has genes that lead it to be

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Speaker 1: a total killer. It's just a go getter. It sees moving,

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Speaker 1: it's like gonna eat that. Uh. And this might be

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Speaker 1: very beneficial to this creature when it's trying to survive

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Speaker 1: in the wild. It's it's very good at chasing down things,

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Speaker 1: killing them and eating them. But these same genes also

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Speaker 1: sometimes they get applied in the wrong direction. Yeah, like

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Speaker 1: to anthrommorphize the situation. It's it's like imagining that the

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Speaker 1: spider or the scorpion in the scenario, it was like

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Speaker 1: a a female wrestler who, in the act of making love,

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Speaker 1: cannot help like a muscle memory, just an instincts kick

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Speaker 1: in and she has to throw a suplex or two

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Speaker 1: or put somebody in a submission hold. Um, she's just

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Speaker 1: the female in this scenario is just so aggressive, just

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Speaker 1: so just amped up and ready to go, that the

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Speaker 1: predatory nature just kicks in and she ends up consuming

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Speaker 1: the part or all of the male. Yeah. Now, is

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Speaker 1: there any evidence for this? I think there's some. Yeah,

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Speaker 1: it depends. I mean in some species of spider. Yes,

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Speaker 1: researchers have observed higher sexual cannibals rates among females that

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Speaker 1: also attacked prey at a faster rate than other females

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Speaker 1: they've observed. I want to talk about one of these

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Speaker 1: studies in a bit, Okay, but then another species there's

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Speaker 1: no correlation. So that's the That's one of the issues too,

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Speaker 1: is you're dealing with You're not dealing with just one

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Speaker 1: species that's engaging in sexual cannibalism. You're dealing in multiple species. Uh.

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Speaker 1: The some are rather diverse from one another that have

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Speaker 1: in many cases independently evolved this adaptation. Yeah. Now, one

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Speaker 1: one hypothesis I saw just kind of mentioned on the internet,

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Speaker 1: but I didn't see in any of the scientific literature

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Speaker 1: I was looking at was the mistaken identity hypothesis. I

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Speaker 1: couldn't tell if there's really anything to this the I

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Speaker 1: saw it mentioned. I mean, the basic idea here is

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Speaker 1: the female is saying, are you food? Are you my lover? Well,

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Speaker 1: let me just take a bite out of you. I

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Speaker 1: can't tell, I guess you're my enemy. I'll just bite

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Speaker 1: into you. Uh. The only place that I saw this

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Speaker 1: and this is the person who kicks people in the

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Speaker 1: face because he's near sighted, right, exactly, enemy or lover,

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Speaker 1: I think the enemy I'm gonna kick. Yeah. So the

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Speaker 1: only place I saw this mentioned was in um uh

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Speaker 1: Kenwyn Blake Subtle's paper The Evolution of Sexual Cannibalism uh,

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Speaker 1: and he said that there's just no empirical evidence to

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Speaker 1: support this theory. Uh. For instance, he says that the

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Speaker 1: the fight up spiders offer a strong argument against mistaken

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Speaker 1: identity because, particularly among the Salta sids, you have the

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Speaker 1: highest visual acuity of all aractans. So I think that's

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Speaker 1: jumping spiders, right, Yes, And he tells us that when

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Speaker 1: you take into account um cannibalism during and after a copulation,

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Speaker 1: that would seem to even further eliminate the possibility. So

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Speaker 1: that the idea here is that, yeah, they're not just

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Speaker 1: blind dummies in these cases. They they have senses available

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Speaker 1: to them to determine if this is a member of

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Speaker 1: their own species or a solid uh outsider prey species. Yeah. Now,

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Speaker 1: of course, one other hypothesis that we could say competes

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Speaker 1: with these and and maybe sometimes overlaps with them, is

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Speaker 1: that it's just it's sexual selection. Yeah, it's it's females

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Speaker 1: being choosy about which males they mate with or whether

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Speaker 1: intentionally or not. Um, and this is encouraging pairing with

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Speaker 1: stronger or fitter or more appropriate males through a tendency

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Speaker 1: to eat the males. Yeah, it's just it's kind of

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Speaker 1: h it's not it's not me, it's use scenario. So

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Speaker 1: I'm going to eat you instead. You're not really uh,

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Speaker 1: you're not really husband material. Maybe you're more meal material. Right,

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Speaker 1: So yeah, that the basic hypothesis here entails the notion

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Speaker 1: that the cannibal female just rejects unacceptable males and eats them,

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Speaker 1: and it's smaller unfit males are better suited as meals.

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Speaker 1: Larger ones are the better mates. Though you also see

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Speaker 1: this reversed in some cases, with females favoring small aller mates. Uh. Again,

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Speaker 1: it kind of depends on the species, right well, As

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Speaker 1: we know from so many great evolutionary biologists before, it's

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Speaker 1: not always the strongest that's the fittest. The bigger doesn't

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Speaker 1: always necessarily mean better. Fitter can mean a lot of

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Speaker 1: different things in different environments, and the environment can include

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Speaker 1: the sexual selection environment, the gene environment in which you're competing. Yeah,

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Speaker 1: and the mere fact that both varieties survive often indicates

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Speaker 1: that both are valued forms of that species. Uh. And

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Speaker 1: there are a number of different mate choice splinter theories

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Speaker 1: as well, um running the anthropomorphic gamut for all the

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Speaker 1: reasons you might you know, mate reject or cannibalize your

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Speaker 1: spider lever so that you have it. Are those are

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Speaker 1: the basic theories regarding sexual capitalism. All right, So now

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Speaker 1: I think it's time to take a quick break. But

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Speaker 1: when we come back, we're going to take a look

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Speaker 1: at our rogues gallery of cannibals. All right, we're back.

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Speaker 1: Who do we have? First year? Joe? Well, I thought

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Speaker 1: it would be interesting because of a specific study I

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Speaker 1: found to look at the cannibalistic burrowing wolf spider, the

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Speaker 1: Lycosa Hispanica. And this is from a paper called does

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Speaker 1: female personality determine mate choice through sexual Cannibalism? It was

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Speaker 1: published in the journal Ethology in and Uh. It was

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Speaker 1: carried out by some research group at the Experimental Station

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Speaker 1: of Arid Zones e Z A C S I C

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Speaker 1: in Spain. And and here's what's going on. Sometimes you

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Speaker 1: want to eat your mate, but you cannot wait for

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Speaker 1: the mating. This is a problem because obviously, so we've

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Speaker 1: talked about the benefits for the female of sexual cannibalism.

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Speaker 1: She gets to mate, and she gets to pass on

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Speaker 1: her genes, and she also gets a meal. And we've

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Speaker 1: been debating the benefits for the male. But what if

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Speaker 1: the mail eats She wants to eat the mate so

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Speaker 1: bad that she eats him before they mate. I mean,

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Speaker 1: that seems like a maladaptive. It seems like it's gotten

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Speaker 1: out of control here. Yeah, And what they found is

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Speaker 1: that this happens a lot. Actually, so sometimes this specific tarantula,

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Speaker 1: This wolf spider doesn't even wait for sex before eating

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Speaker 1: the potential mate. So why is that? What determines if

426
00:24:28,520 --> 00:24:33,240
Speaker 1: the female wolf spider attacks a potential mate before the mating.

427
00:24:34,040 --> 00:24:36,520
Speaker 1: Is it how hungry she is? If so, this would

428
00:24:36,560 --> 00:24:41,160
Speaker 1: support the adaptive foraging hypothesis perhaps or is it her

429
00:24:41,200 --> 00:24:44,080
Speaker 1: personality and if that's the case, it might support the

430
00:24:44,080 --> 00:24:47,879
Speaker 1: aggressive spillover. Is it the fitness of the male? This

431
00:24:47,960 --> 00:24:51,600
Speaker 1: might support some form of sexual selection or mate choice.

432
00:24:52,800 --> 00:24:55,800
Speaker 1: So the researchers decided to try to isolate these and

433
00:24:56,080 --> 00:24:58,159
Speaker 1: figure out which one is the most likely. So they

434
00:24:58,240 --> 00:25:01,160
Speaker 1: studied a group of female wolves by to see how

435
00:25:01,200 --> 00:25:05,800
Speaker 1: aggressive they were in feeding. And some were insanely aggressive

436
00:25:05,880 --> 00:25:08,720
Speaker 1: that they were just going to town immediately on any

437
00:25:08,800 --> 00:25:12,960
Speaker 1: prey such as beatles, while others were more cautious or

438
00:25:13,000 --> 00:25:17,479
Speaker 1: they used the term docile, which I thought was funny.

439
00:25:17,560 --> 00:25:20,600
Speaker 1: Essentially more reticent hunters, they just didn't jump on prey

440
00:25:20,720 --> 00:25:23,920
Speaker 1: quite as quickly. And then they took these same females

441
00:25:23,960 --> 00:25:27,400
Speaker 1: they had studied and offered the females a random selection

442
00:25:27,440 --> 00:25:31,120
Speaker 1: of males for mating to see what would happen. Uh,

443
00:25:31,160 --> 00:25:34,240
Speaker 1: And you know what. The female personality actually seemed to

444
00:25:34,240 --> 00:25:35,879
Speaker 1: play a big role. So I want to read a

445
00:25:35,960 --> 00:25:39,120
Speaker 1: quote from a press release by one of the study authors,

446
00:25:39,160 --> 00:25:44,280
Speaker 1: Reuben robin Ada Bueno uh And. The author said, more

447
00:25:44,320 --> 00:25:48,760
Speaker 1: cannibalistic females were also more voracious towards their prey and

448
00:25:48,800 --> 00:25:52,240
Speaker 1: thus better nourished. This is surprising since they have more

449
00:25:52,320 --> 00:25:56,320
Speaker 1: nutritive resources to invest in their offspring before finding the

450
00:25:56,400 --> 00:25:59,840
Speaker 1: first males, and then said their priority should be in

451
00:26:00,119 --> 00:26:02,919
Speaker 1: suring the firm s fertilization of their eggs instead of

452
00:26:02,960 --> 00:26:07,200
Speaker 1: eliminating their potential donors. So this is kind of counterintuitive.

453
00:26:07,240 --> 00:26:09,760
Speaker 1: You might expect that the hungry or the female, the

454
00:26:09,840 --> 00:26:12,679
Speaker 1: more likely she would eat the male, but that's not

455
00:26:12,800 --> 00:26:16,960
Speaker 1: what they found. And the more aggressive females they pounced

456
00:26:16,960 --> 00:26:19,960
Speaker 1: on the pre war they also ate more, They were

457
00:26:20,080 --> 00:26:24,040
Speaker 1: less hungry, and they were more likely to attack, kill,

458
00:26:24,080 --> 00:26:28,239
Speaker 1: and eat the males. So it sounds a little bit

459
00:26:28,280 --> 00:26:31,160
Speaker 1: more like aggressive spill over to me. Yeah. So unless

460
00:26:31,200 --> 00:26:33,320
Speaker 1: it's an aggressive spill over, it would seem to be

461
00:26:33,359 --> 00:26:38,200
Speaker 1: evolutionarily counterintuitive. Is that she she's well nourished, she should

462
00:26:38,240 --> 00:26:41,800
Speaker 1: be prioritizing the fertilization of her eggs. Instead, she just

463
00:26:41,960 --> 00:26:45,480
Speaker 1: kills and eats her potential mates. But this makes it

464
00:26:45,520 --> 00:26:49,119
Speaker 1: look like baseline predation tendencies play a larger role in

465
00:26:49,240 --> 00:26:52,320
Speaker 1: whether or not the male gets eaten. Uh. Though you

466
00:26:52,359 --> 00:26:55,280
Speaker 1: could possibly also look at this and interpret it as

467
00:26:55,320 --> 00:26:58,840
Speaker 1: a form of mate testing, like you know, the weaker

468
00:26:58,880 --> 00:27:00,679
Speaker 1: males are the ones who are more were likely to

469
00:27:00,920 --> 00:27:05,480
Speaker 1: get eaten. Yeah, alright. The next one we have here

470
00:27:05,600 --> 00:27:10,720
Speaker 1: is the raft spider, and this is UH Dolomedes fimbriatis.

471
00:27:11,000 --> 00:27:12,879
Speaker 1: And according to a two thousand fifteen study from the

472
00:27:12,960 --> 00:27:17,080
Speaker 1: University of Melbourne, these spiders do seem to be testing

473
00:27:17,160 --> 00:27:20,479
Speaker 1: the males. This would be mate fitness rather than engaging

474
00:27:20,480 --> 00:27:23,440
Speaker 1: in an aggressive spill over. Okay, how does this work? Well,

475
00:27:23,560 --> 00:27:26,000
Speaker 1: this is how they they They studied it. They watched

476
00:27:26,080 --> 00:27:29,200
Speaker 1: a bunch of spiders mate, of course, yes, they watched. Yeah.

477
00:27:29,200 --> 00:27:32,480
Speaker 1: The first trial consisted of eleven solving that eleven of

478
00:27:32,560 --> 00:27:37,520
Speaker 1: sixteen females copulated then attacked the males deering or immediately

479
00:27:37,560 --> 00:27:41,320
Speaker 1: after population. Uh. Four of these attacks were fatal. Then

480
00:27:41,320 --> 00:27:43,720
Speaker 1: they did a second trial where six of eight females

481
00:27:43,800 --> 00:27:47,440
Speaker 1: that copulated attacked the males with two fatalities. So this

482
00:27:47,520 --> 00:27:50,440
Speaker 1: is interesting. Even in these UH I think one thing

483
00:27:50,440 --> 00:27:52,760
Speaker 1: we should point out is that even in these species

484
00:27:52,760 --> 00:27:56,760
Speaker 1: that practice sexual cannibalism, it doesn't always happen, right, Yeah,

485
00:27:57,119 --> 00:28:01,119
Speaker 1: So in these cases, aggression love did not seem to

486
00:28:01,119 --> 00:28:03,800
Speaker 1: play a factor. So again they're they're looking at how

487
00:28:03,800 --> 00:28:06,840
Speaker 1: aggressive a hunter does. This female appear to be outside

488
00:28:06,840 --> 00:28:11,920
Speaker 1: the context of mating. Rather male size, female age, and

489
00:28:12,040 --> 00:28:16,000
Speaker 1: her virginity seem to be more important factors. So females

490
00:28:16,000 --> 00:28:19,640
Speaker 1: were marginally more likely to attack smaller males. I don't

491
00:28:19,640 --> 00:28:22,040
Speaker 1: know if there's another word for this, but I kept

492
00:28:22,080 --> 00:28:25,560
Speaker 1: seeing this pop up over and over again, the virginity

493
00:28:25,880 --> 00:28:28,760
Speaker 1: of a spider. It just seems like it would that

494
00:28:28,840 --> 00:28:32,080
Speaker 1: seems like such a human word. Uh, Like it's weird

495
00:28:32,119 --> 00:28:34,200
Speaker 1: to think of a spider. I don't know, it would

496
00:28:34,200 --> 00:28:36,119
Speaker 1: just seem to make more sense to say a spider

497
00:28:36,119 --> 00:28:39,120
Speaker 1: who had not yet made it. Yeah, spider virginity, or

498
00:28:39,200 --> 00:28:42,240
Speaker 1: certainly virginity of a spider sounds like a wonderful name

499
00:28:42,280 --> 00:28:47,240
Speaker 1: for a short horror collection, but actually will explore in

500
00:28:47,520 --> 00:28:50,080
Speaker 1: a in another example I'm gonna get to in a bit,

501
00:28:50,400 --> 00:28:54,480
Speaker 1: you'll see where spider virginity, for lack of a better word,

502
00:28:54,760 --> 00:28:58,880
Speaker 1: does become more of an important consideration in sexual cannibalism. Yeah. Now,

503
00:28:59,080 --> 00:29:02,880
Speaker 1: one other inter seeing consideration to take into account is

504
00:29:03,240 --> 00:29:09,120
Speaker 1: the male decision making process in sexual cannibalism cases. So,

505
00:29:09,120 --> 00:29:13,520
Speaker 1: so a male is approaching a potential mate. He I

506
00:29:13,560 --> 00:29:16,080
Speaker 1: want to say he knows. I mean again, it's an insect,

507
00:29:16,160 --> 00:29:19,160
Speaker 1: so he probably doesn't really consciously know, but something about

508
00:29:19,240 --> 00:29:24,280
Speaker 1: his behavioral programming quote knows that he might get eaten

509
00:29:24,600 --> 00:29:27,400
Speaker 1: in some scenarios. So he has to do a kind

510
00:29:27,440 --> 00:29:32,480
Speaker 1: of behavioral cost benefit analysis. What what makes a delicious

511
00:29:32,600 --> 00:29:36,280
Speaker 1: bachelor insects decide to roll the dice with a hungry

512
00:29:36,320 --> 00:29:39,800
Speaker 1: female in the case of something like a praying mantis,

513
00:29:39,800 --> 00:29:43,680
Speaker 1: where the female in many cases eats the male during

514
00:29:43,800 --> 00:29:47,959
Speaker 1: or after sex. So there's a paper published in Plos

515
00:29:48,000 --> 00:29:51,520
Speaker 1: one that explores these decision factors and mate choice in

516
00:29:51,560 --> 00:29:56,040
Speaker 1: sexual cannibalism. UH in praying mantises is called low mate

517
00:29:56,120 --> 00:30:03,000
Speaker 1: encounter rate increases male risk taking in sexual cannibalistic praying mantis. Um.

518
00:30:03,080 --> 00:30:06,040
Speaker 1: So you've got a male of a praying mantis species

519
00:30:06,040 --> 00:30:09,800
Speaker 1: like tin Odera sinensis and this is this is a

520
00:30:09,920 --> 00:30:12,160
Speaker 1: common praying mantis. So I think it's referred to as

521
00:30:12,240 --> 00:30:15,920
Speaker 1: Chinese mantis. But it uh it has to make a

522
00:30:15,960 --> 00:30:19,160
Speaker 1: calculation of risk versus reward when approaching a female. Now,

523
00:30:19,160 --> 00:30:21,960
Speaker 1: I've read in one source that about sixteen percent of

524
00:30:21,960 --> 00:30:25,120
Speaker 1: the time a male of this species copulates with a

525
00:30:25,160 --> 00:30:28,600
Speaker 1: female in the wild, he gets slaughtered and eaten. So

526
00:30:29,240 --> 00:30:31,800
Speaker 1: those aren't good numbers. I mean, you wouldn't want to

527
00:30:31,840 --> 00:30:34,840
Speaker 1: copulate if you've got slaughtered sixteen percent of the time.

528
00:30:35,360 --> 00:30:37,440
Speaker 1: Uh So there's a chance of getting eaten. But of

529
00:30:37,480 --> 00:30:40,680
Speaker 1: course there's also the positive, a chance of reproducing. So

530
00:30:40,720 --> 00:30:43,520
Speaker 1: how does the male decide whether to roll the dice?

531
00:30:44,040 --> 00:30:46,520
Speaker 1: And the authors of this study point out two major

532
00:30:46,560 --> 00:30:50,720
Speaker 1: factors to consider. Number one is the level of predatory

533
00:30:50,840 --> 00:30:54,360
Speaker 1: risk imposed by the females, so some females are more

534
00:30:54,400 --> 00:30:57,160
Speaker 1: likely to eat you than other ones. And number two

535
00:30:57,600 --> 00:31:01,200
Speaker 1: is the frequency of mating opportunities for males. How many

536
00:31:01,280 --> 00:31:04,320
Speaker 1: chances has this male had to copulate with other females.

537
00:31:05,240 --> 00:31:08,920
Speaker 1: So to study these things, the researchers artificially controlled the

538
00:31:09,000 --> 00:31:13,040
Speaker 1: dating pool. Essentially, specifically, they allowed some males of this

539
00:31:13,240 --> 00:31:16,600
Speaker 1: praying man of species to encounter and court more females

540
00:31:16,640 --> 00:31:20,040
Speaker 1: than others, and then they controlled the risk of predation

541
00:31:20,160 --> 00:31:23,600
Speaker 1: by the females on the males. One thing to notice

542
00:31:23,640 --> 00:31:25,840
Speaker 1: that a male, a male can tell when a female

543
00:31:25,920 --> 00:31:29,520
Speaker 1: is hungry, and the hungrier she is, the more cautious

544
00:31:29,560 --> 00:31:33,080
Speaker 1: they are. However, what they found is that if the

545
00:31:33,200 --> 00:31:37,600
Speaker 1: male is sex starved, he will take risks with hungrier females.

546
00:31:38,360 --> 00:31:40,320
Speaker 1: And in the wild, it's worth pointing out, as we

547
00:31:40,360 --> 00:31:42,520
Speaker 1: said earlier, most of the time you're going to be

548
00:31:42,560 --> 00:31:44,880
Speaker 1: on the verge of starvation. Females in the wild are

549
00:31:44,960 --> 00:31:48,840
Speaker 1: usually hungry. So what what did they find? They found

550
00:31:48,920 --> 00:31:53,760
Speaker 1: sexually frustrated males are and those are again sorry anthropomorphic language.

551
00:31:53,800 --> 00:31:57,280
Speaker 1: The males who had had fewer chances to encounter females

552
00:31:57,320 --> 00:32:00,200
Speaker 1: in court them the ones that are sexually frustrated. We're

553
00:32:00,200 --> 00:32:03,560
Speaker 1: willing to take more risks with more dangerous females in

554
00:32:03,640 --> 00:32:06,360
Speaker 1: return for chances to mate. And the males who had

555
00:32:06,440 --> 00:32:09,560
Speaker 1: had more time around females, had been exposed to more females,

556
00:32:09,680 --> 00:32:13,640
Speaker 1: they were more cautious, approached the females more slowly and

557
00:32:13,720 --> 00:32:17,920
Speaker 1: stayed farther away. Um, And the ones who had not

558
00:32:17,960 --> 00:32:20,200
Speaker 1: been exposed to females, they basically just said to hell

559
00:32:20,240 --> 00:32:23,360
Speaker 1: with it and they ran in there. Okay, So yeah,

560
00:32:23,360 --> 00:32:25,640
Speaker 1: it comes down to what kind of risk are they

561
00:32:25,640 --> 00:32:28,880
Speaker 1: willing to take to carry out their genetic mission. Yeah,

562
00:32:28,920 --> 00:32:31,200
Speaker 1: and then there was also a second experiment where the

563
00:32:31,200 --> 00:32:35,000
Speaker 1: researchers tried this with hungry females and well fed females,

564
00:32:35,360 --> 00:32:38,600
Speaker 1: and they found that the hungry females plus sexually frustrated

565
00:32:38,640 --> 00:32:42,800
Speaker 1: males that that combination did in fact lead to cannibalism. Uh.

566
00:32:42,840 --> 00:32:45,800
Speaker 1: They said, quote greater risk taking behavior by males with

567
00:32:45,960 --> 00:32:49,400
Speaker 1: low mate encounter rates resulted in high rates of sexual

568
00:32:49,440 --> 00:32:53,480
Speaker 1: cannibalism when these males were paired with hungry females. So

569
00:32:53,520 --> 00:32:56,760
Speaker 1: it essentially paints a picture of how to make a

570
00:32:56,840 --> 00:33:01,400
Speaker 1: male praying mantis suicidal. You take away his access to

571
00:33:01,760 --> 00:33:04,760
Speaker 1: two lady friends. Hey, yeah, there you go. Okay, but

572
00:33:04,800 --> 00:33:06,720
Speaker 1: we we should look, we should get back to some spiders,

573
00:33:06,760 --> 00:33:10,880
Speaker 1: because the classic example of sexual cannibalism in the wild

574
00:33:11,000 --> 00:33:13,080
Speaker 1: is going to be the black widow. But but let's

575
00:33:13,120 --> 00:33:15,840
Speaker 1: let's look at a relative of the black widow. That's right,

576
00:33:15,840 --> 00:33:19,040
Speaker 1: We're gonna look at the red back spiders who are relatives,

577
00:33:19,040 --> 00:33:22,040
Speaker 1: and they have males, they're seemingly quite willing to take

578
00:33:22,080 --> 00:33:25,320
Speaker 1: the risk of being cannibalized. It's another one of these

579
00:33:25,320 --> 00:33:28,600
Speaker 1: species where we see some some rather intense uh sexual

580
00:33:28,600 --> 00:33:33,200
Speaker 1: dimorphism here because the uh, the the females are are

581
00:33:33,280 --> 00:33:37,960
Speaker 1: far larger while the males are tiny about the size

582
00:33:38,000 --> 00:33:40,440
Speaker 1: of a grain of rice. Females live for up to

583
00:33:40,520 --> 00:33:43,120
Speaker 1: two years, while males generally only make it four to

584
00:33:43,200 --> 00:33:47,120
Speaker 1: eight weeks. Oh man, Yeah, so so that's one example.

585
00:33:47,120 --> 00:33:49,520
Speaker 1: Like we were talking about at the beginning, like we

586
00:33:49,520 --> 00:33:52,400
Speaker 1: we can't help but overlaying our sort of social values

587
00:33:52,440 --> 00:33:54,840
Speaker 1: onto the lives of these insects. But it really does

588
00:33:54,880 --> 00:33:58,440
Speaker 1: look there like the female is what's being valued somehow

589
00:33:58,480 --> 00:34:01,120
Speaker 1: by nature and the male is just kind of there

590
00:34:01,160 --> 00:34:04,280
Speaker 1: to provide some sperm and disappear. Yeah, and then you

591
00:34:04,320 --> 00:34:07,520
Speaker 1: know it also comes from our attachment to life, I

592
00:34:07,560 --> 00:34:10,040
Speaker 1: think too, where you say, well, one lives longer, one's

593
00:34:10,120 --> 00:34:12,200
Speaker 1: got a bigger body, one seems to have more of

594
00:34:12,280 --> 00:34:15,640
Speaker 1: a sensory experience of the world, whereas I mean, it

595
00:34:15,680 --> 00:34:18,880
Speaker 1: really comes down to they each have their genetic mission,

596
00:34:19,080 --> 00:34:23,040
Speaker 1: they both carry it out. Ultimately, Hey, you could say

597
00:34:23,040 --> 00:34:25,839
Speaker 1: the male wins because he did it faster, we got

598
00:34:25,880 --> 00:34:30,239
Speaker 1: to the finish line mission accomplished, uh, no longer wasting resources.

599
00:34:31,320 --> 00:34:35,440
Speaker 1: But during copulation among the red back spiders, the smaller

600
00:34:35,520 --> 00:34:39,320
Speaker 1: male spider positions itself above the female's jaws. And this

601
00:34:39,520 --> 00:34:42,200
Speaker 1: apparent to male here I am, yeah, here, i am,

602
00:34:42,239 --> 00:34:45,280
Speaker 1: I'm right here, And it's apparent the male complicity, complicity

603
00:34:45,320 --> 00:34:49,759
Speaker 1: and sexual cannibalism is favored by sexual selection because cannibalized

604
00:34:49,880 --> 00:34:54,440
Speaker 1: spiders receive a number of paternity advantages. Oh really, so

605
00:34:54,480 --> 00:34:57,920
Speaker 1: they're they're documented cases here that show that it's better

606
00:34:58,000 --> 00:35:01,239
Speaker 1: to be cannibalized. So it would seem so genetically better,

607
00:35:01,760 --> 00:35:03,880
Speaker 1: not so much for the individual. Yeah, but again then

608
00:35:03,920 --> 00:35:08,600
Speaker 1: we're ben we're projecting conscious experience onto these these guys.

609
00:35:08,640 --> 00:35:13,240
Speaker 1: So cannibalized males copulate longer and they fertilize more eggs

610
00:35:13,280 --> 00:35:18,520
Speaker 1: than those who survive. Okay, so that's one advantage. Another advantage,

611
00:35:18,600 --> 00:35:22,920
Speaker 1: females are more likely to reject subsequent suitors after consuming

612
00:35:22,920 --> 00:35:26,880
Speaker 1: their first mate. Uh. And these results represented to empirical

613
00:35:26,920 --> 00:35:30,920
Speaker 1: evidence for uh what is sometimes referred to as male

614
00:35:31,400 --> 00:35:35,160
Speaker 1: copulatory suicide as an adapted behavior. And of course, but

615
00:35:35,200 --> 00:35:39,719
Speaker 1: of course that's a highly anthropomorphizing term. So two, back

616
00:35:39,760 --> 00:35:42,880
Speaker 1: to our analogy that this is again saying, this strangely

617
00:35:43,040 --> 00:35:47,160
Speaker 1: counterintuitive seeming behavior is itself being selected for. It's not

618
00:35:47,239 --> 00:35:50,680
Speaker 1: like a byproduct of something, it is itself the trait

619
00:35:50,880 --> 00:35:54,640
Speaker 1: that's beneficial. Kicking people in the face is good, yes,

620
00:35:55,400 --> 00:35:58,560
Speaker 1: And then there's this Uh. They deposit a sperm plug

621
00:35:58,880 --> 00:36:01,480
Speaker 1: and so this is a small part of their copula

622
00:36:01,520 --> 00:36:05,480
Speaker 1: tory organ that stays inside the female uh. And then

623
00:36:05,480 --> 00:36:08,960
Speaker 1: it prevents any future males from successfully fertilizing her eggs,

624
00:36:08,960 --> 00:36:12,360
Speaker 1: meaning that males have to mate with a virgin spider

625
00:36:12,800 --> 00:36:19,560
Speaker 1: to maximize their reproductive success. So competition is tough then

626
00:36:19,680 --> 00:36:22,840
Speaker 1: for the male redback spider for a couple of different

627
00:36:22,840 --> 00:36:25,880
Speaker 1: reasons here. And they only get that one mating opportunity

628
00:36:25,880 --> 00:36:27,759
Speaker 1: to carry it out. That's it. And given the whole

629
00:36:27,760 --> 00:36:30,759
Speaker 1: sperm plug thing, they have to act fast and they

630
00:36:30,800 --> 00:36:33,359
Speaker 1: also might get eaten, so so be it. But they

631
00:36:33,560 --> 00:36:35,840
Speaker 1: also have to make sure that they have enough energy

632
00:36:35,920 --> 00:36:39,319
Speaker 1: to carry out the deed. Interesting yeah, and this is

633
00:36:39,360 --> 00:36:42,000
Speaker 1: so they might not they might fail, they might be

634
00:36:42,040 --> 00:36:45,840
Speaker 1: too weary to survive the copulation long and or not survive,

635
00:36:45,920 --> 00:36:48,960
Speaker 1: but to perform the copulation correctly, right, And this is

636
00:36:48,960 --> 00:36:51,200
Speaker 1: where we get into I think it's helpful to think

637
00:36:51,200 --> 00:36:54,719
Speaker 1: of the mail and a weaponized sense as a he is.

638
00:36:54,880 --> 00:36:57,759
Speaker 1: He is a warhead, that is that has sent on

639
00:36:57,800 --> 00:37:00,480
Speaker 1: a mission to reach a destination. He to have the

640
00:37:00,560 --> 00:37:05,440
Speaker 1: appropriate navigational tools and fuel to to reach that destination.

641
00:37:05,880 --> 00:37:09,520
Speaker 1: But as it is with you know in rocketry, you

642
00:37:09,520 --> 00:37:12,160
Speaker 1: you don't you don't want to supply too much fuel.

643
00:37:12,200 --> 00:37:14,040
Speaker 1: You want just enough fuel to get where you're going, right,

644
00:37:14,440 --> 00:37:17,000
Speaker 1: And that actually plays into the development of the male

645
00:37:17,120 --> 00:37:20,880
Speaker 1: redback spider. According to a two thousand six University of

646
00:37:20,880 --> 00:37:24,759
Speaker 1: Toronto study, the speed of their development actually depends on

647
00:37:24,800 --> 00:37:28,520
Speaker 1: the density of females in the surroundings. When males can

648
00:37:28,560 --> 00:37:33,799
Speaker 1: smell females in abundance, they develop rapidly, settling for a

649
00:37:33,880 --> 00:37:39,759
Speaker 1: smaller body size and less fat reserves. All also that

650
00:37:39,760 --> 00:37:42,600
Speaker 1: he can get to those virgin females sooner and if

651
00:37:42,600 --> 00:37:45,239
Speaker 1: there are if there are plenty around, he doesn't need

652
00:37:45,280 --> 00:37:47,920
Speaker 1: the fat preserves in order to survive a long search

653
00:37:48,000 --> 00:37:51,719
Speaker 1: for a mate. But likewise, if he can smell um,

654
00:37:51,760 --> 00:37:54,120
Speaker 1: you know, he doesn't smell any females in the vicinity,

655
00:37:54,239 --> 00:37:56,279
Speaker 1: or they're very few, then they're gonna go ahead and

656
00:37:56,320 --> 00:37:59,440
Speaker 1: develop those those fat reserves so that he can actually

657
00:37:59,480 --> 00:38:03,440
Speaker 1: survive a longer trip. Oh wow, So it's sexually strategic

658
00:38:03,520 --> 00:38:06,640
Speaker 1: storage of energy. Yeah, exactly. And if there are a

659
00:38:06,680 --> 00:38:08,880
Speaker 1: lot of males in the area already, they tend to

660
00:38:08,920 --> 00:38:12,520
Speaker 1: go smaller on size, but with greater fat stores to

661
00:38:12,560 --> 00:38:16,239
Speaker 1: sustain them through. And I love this. The extended courtship

662
00:38:16,320 --> 00:38:19,480
Speaker 1: rituals in which the male has to essentially play music

663
00:38:19,560 --> 00:38:23,720
Speaker 1: on the female's web, just like strumming like the chords,

664
00:38:23,760 --> 00:38:26,879
Speaker 1: for up to eight hours at a time. What Yeah,

665
00:38:26,960 --> 00:38:30,320
Speaker 1: And if apparently she doesn't like the song he's playing,

666
00:38:30,600 --> 00:38:33,160
Speaker 1: she doesn't necessarily eat him. She may just swat him

667
00:38:33,160 --> 00:38:36,640
Speaker 1: off the web. We we are just we are jumping

668
00:38:36,640 --> 00:38:40,600
Speaker 1: the anthropomorphism shark here, I am. I am so sorry

669
00:38:40,600 --> 00:38:42,840
Speaker 1: to the people who don't want to hear the anthropomorphism

670
00:38:42,920 --> 00:38:45,200
Speaker 1: because we have gone off the demon. How is there

671
00:38:45,239 --> 00:38:47,960
Speaker 1: any way we could do this topic otherwise? For some reason,

672
00:38:48,120 --> 00:38:52,440
Speaker 1: it just demands this biased, inappropriate language. I think the

673
00:38:52,480 --> 00:38:56,200
Speaker 1: thing is, if you strip away the anti anthropomorphism, it

674
00:38:56,320 --> 00:39:00,920
Speaker 1: ultimately becomes less interesting to talk about. That's interesting to

675
00:39:01,000 --> 00:39:04,160
Speaker 1: listen to and harder to convey because instead of saying,

676
00:39:04,200 --> 00:39:06,600
Speaker 1: he plays their love song on a spiderweb, I have

677
00:39:06,640 --> 00:39:10,640
Speaker 1: to get into a little into far stuffier um biological

678
00:39:10,719 --> 00:39:14,480
Speaker 1: language about what's actually going on, and ultimately I'm conveying

679
00:39:14,520 --> 00:39:17,560
Speaker 1: the same thing, Like it's either you're easier just to say, hey,

680
00:39:17,600 --> 00:39:21,200
Speaker 1: this is gonna be a little anthropomorphic, so just be aware.

681
00:39:22,920 --> 00:39:24,880
Speaker 1: Well I didn't mean that as a criticism. I mean

682
00:39:24,960 --> 00:39:28,880
Speaker 1: I'm doing it too. Uh yeah, I mean, what what

683
00:39:28,920 --> 00:39:31,000
Speaker 1: does it take though, for a spider to become good

684
00:39:31,040 --> 00:39:33,719
Speaker 1: at playing the strings? Does he have to practice? I

685
00:39:33,760 --> 00:39:37,160
Speaker 1: don't know. It's certainly not extensive practice because he really

686
00:39:37,200 --> 00:39:40,200
Speaker 1: has to jump right in there, right. Yeah. So here's

687
00:39:40,239 --> 00:39:42,920
Speaker 1: one thing I was wondering. It seems like in every

688
00:39:42,960 --> 00:39:46,440
Speaker 1: case we look at of sexual cannibalism, it's the female

689
00:39:46,480 --> 00:39:49,200
Speaker 1: eating the male. And this obviously makes sense because the

690
00:39:49,200 --> 00:39:52,920
Speaker 1: female is the egg carrying member of the species. So

691
00:39:53,080 --> 00:39:55,480
Speaker 1: I mean, it just wouldn't make sense for a male

692
00:39:55,600 --> 00:39:58,680
Speaker 1: to eat a female after copulation, because that would destroy

693
00:39:58,719 --> 00:40:02,040
Speaker 1: all chances of reproduction happening from the you know, you

694
00:40:02,080 --> 00:40:05,120
Speaker 1: would eat the female and then the fertilized eggs would

695
00:40:05,120 --> 00:40:09,440
Speaker 1: not survive probably, and then what was the point of copulation?

696
00:40:09,520 --> 00:40:12,279
Speaker 1: That just seems like wasted energy resources. But is there

697
00:40:12,320 --> 00:40:15,920
Speaker 1: any case where some version of this could happen? There is,

698
00:40:16,000 --> 00:40:19,240
Speaker 1: interestingly enough we do find an example of reverse sexual

699
00:40:19,280 --> 00:40:25,200
Speaker 1: cannibalism in the mi Carria sociabilist spiders. It essentially boils

700
00:40:25,239 --> 00:40:28,600
Speaker 1: down to a form of mate male mate selection, much

701
00:40:28,640 --> 00:40:32,280
Speaker 1: like that employed by various female cannibals. So I see

702
00:40:32,360 --> 00:40:35,440
Speaker 1: that it depends kind of when you when you discuss

703
00:40:35,600 --> 00:40:39,839
Speaker 1: like how unrealistic would male sexual cannibalism be, It kind

704
00:40:39,840 --> 00:40:42,160
Speaker 1: of depends on which theory you're throwing at it. So

705
00:40:42,200 --> 00:40:45,120
Speaker 1: if you're going with the mate selection, yeah, you could

706
00:40:45,120 --> 00:40:48,640
Speaker 1: see where a male could say, Nope, don't want to

707
00:40:48,640 --> 00:40:51,720
Speaker 1: breathe with that that female. That breeding with that female

708
00:40:51,880 --> 00:40:54,840
Speaker 1: is not going to give me optimal results on my

709
00:40:54,920 --> 00:40:58,400
Speaker 1: genetic mission here. Better off that I eat her, okay, okay.

710
00:40:58,640 --> 00:41:01,480
Speaker 1: And so in two thousands thirteen, a team of researchers

711
00:41:01,680 --> 00:41:05,200
Speaker 1: from Messeric University in the Czech Republic found that young

712
00:41:05,280 --> 00:41:10,600
Speaker 1: males from the summer generation of these particular spiders were

713
00:41:10,600 --> 00:41:13,400
Speaker 1: the were the most likely cannibals here, and they tended

714
00:41:13,440 --> 00:41:18,880
Speaker 1: to cannibalize older females of the previous spring generation. So

715
00:41:19,080 --> 00:41:22,279
Speaker 1: male size and aggressions seem to play a role in

716
00:41:22,320 --> 00:41:26,320
Speaker 1: all of this. Uh, and female virginity or lack thereof,

717
00:41:26,960 --> 00:41:29,960
Speaker 1: did not. So this is another case where we're also

718
00:41:29,960 --> 00:41:33,040
Speaker 1: getting a little bit of the aggression spillover model in

719
00:41:33,080 --> 00:41:36,560
Speaker 1: there as well. Okay, but for the most part, it

720
00:41:36,560 --> 00:41:38,920
Speaker 1: seems to come down to mate selection. Yeah, So it

721
00:41:38,920 --> 00:41:41,600
Speaker 1: seems like we've seen a couple of scenarios where those

722
00:41:41,600 --> 00:41:44,879
Speaker 1: two hypotheses are not necessarily in conflict. They can sort

723
00:41:44,880 --> 00:41:47,480
Speaker 1: of work together, right. You know. One of the things

724
00:41:47,600 --> 00:41:49,359
Speaker 1: that this is kind of a side note, but one

725
00:41:49,360 --> 00:41:51,600
Speaker 1: of the things that's been interesting to me in looking

726
00:41:51,840 --> 00:41:55,719
Speaker 1: at this research is the different examples of uh I

727
00:41:55,760 --> 00:41:58,920
Speaker 1: guess males that can continue the mating process after they

728
00:41:58,960 --> 00:42:03,839
Speaker 1: have been partially consumed or dismembered. Particularly you see this

729
00:42:03,880 --> 00:42:07,000
Speaker 1: with with some of the mantis species out there, right,

730
00:42:07,080 --> 00:42:09,960
Speaker 1: some mantids, the males can continue to mate after their

731
00:42:10,040 --> 00:42:12,759
Speaker 1: their heads bitten off, and I think this is the

732
00:42:12,760 --> 00:42:15,160
Speaker 1: case with some of the spiders too. Write they can

733
00:42:15,200 --> 00:42:19,760
Speaker 1: like they can inject a sexual organ into the female

734
00:42:19,880 --> 00:42:23,239
Speaker 1: and then they can basically be eaten while those individual

735
00:42:23,360 --> 00:42:25,239
Speaker 1: organs are still doing their work. Yeah. I mean, we

736
00:42:25,280 --> 00:42:28,960
Speaker 1: already discussed in one case where the female made it

737
00:42:29,040 --> 00:42:31,640
Speaker 1: longer with the males who were cannibalized. So it's kind

738
00:42:31,680 --> 00:42:35,640
Speaker 1: of like if I'm cool again to anthropomorphize, if I'm

739
00:42:35,640 --> 00:42:38,960
Speaker 1: cool with having my head eaten off, I actually am

740
00:42:38,960 --> 00:42:41,759
Speaker 1: going to get in there longer doing the thing that

741
00:42:41,920 --> 00:42:46,880
Speaker 1: I am designed to do. So it makes sense, right,

742
00:42:47,560 --> 00:42:51,359
Speaker 1: it makes so much sense. Yeah, it's like she's gonna

743
00:42:51,360 --> 00:42:53,680
Speaker 1: eat me, but I'm gonna be there twice as long. Right,

744
00:42:54,480 --> 00:42:58,520
Speaker 1: it all evens out. Now. There was another interesting finding

745
00:42:58,680 --> 00:43:01,480
Speaker 1: that I wanted to talk about, bree Fulee, which was

746
00:43:01,640 --> 00:43:07,280
Speaker 1: about sexual deception in a cannibalistic mating system. Yeah. So,

747
00:43:07,280 --> 00:43:10,720
Speaker 1: so there was a paper published inteen called sexual Deception

748
00:43:10,760 --> 00:43:14,880
Speaker 1: in a Cannibalistic Mating System testing the film Fatale hypothesis.

749
00:43:14,880 --> 00:43:18,600
Speaker 1: And this was by the scientist Catherine L. Berry in

750
00:43:19,200 --> 00:43:23,160
Speaker 1: Biological Sciences, Proceedings of the Royal Society b And this

751
00:43:23,239 --> 00:43:27,600
Speaker 1: was a study of the female false garden mantis. Now,

752
00:43:27,719 --> 00:43:32,440
Speaker 1: what the false garden mantis does is she has pheromones

753
00:43:32,600 --> 00:43:36,960
Speaker 1: that are taken as good faith signals of her fecundity,

754
00:43:37,000 --> 00:43:40,719
Speaker 1: of of how likely she is to produce numbers of

755
00:43:40,760 --> 00:43:44,680
Speaker 1: healthy offspring. So mantis is that are in better health,

756
00:43:44,719 --> 00:43:47,960
Speaker 1: they're in better shape, they're more well fed. They give

757
00:43:48,000 --> 00:43:51,680
Speaker 1: off pheromones that advertise to males like, hey, I'm good

758
00:43:51,719 --> 00:43:54,200
Speaker 1: to go. We we are going to have lots of

759
00:43:54,239 --> 00:43:58,200
Speaker 1: beautiful children together if you come mate with me. But

760
00:43:58,520 --> 00:44:01,719
Speaker 1: also within this mantis ecs, there is some rate of

761
00:44:01,800 --> 00:44:05,320
Speaker 1: sexual cannibalism where the female will eat the male uh

762
00:44:05,560 --> 00:44:09,920
Speaker 1: after or during copulation. So this study was supposed to

763
00:44:10,080 --> 00:44:16,240
Speaker 1: examine UH whether or not the females could lie using

764
00:44:16,280 --> 00:44:20,440
Speaker 1: pheromones about how likely they were, when what and how

765
00:44:20,480 --> 00:44:23,319
Speaker 1: good health they were, you know, uh to to the

766
00:44:23,360 --> 00:44:26,360
Speaker 1: males who were coming up to them. So the females

767
00:44:26,400 --> 00:44:31,320
Speaker 1: were given different feeding regimens. Essentially some of them got

768
00:44:31,800 --> 00:44:35,880
Speaker 1: very good nutrition, others got medium nutrition, some got poor nutrition,

769
00:44:35,960 --> 00:44:39,719
Speaker 1: and some got very poor nutrition. And then males were

770
00:44:39,800 --> 00:44:43,040
Speaker 1: allowed to uh they were they were given the opportunity

771
00:44:43,320 --> 00:44:46,440
Speaker 1: to sort of approach a female that they couldn't see.

772
00:44:46,480 --> 00:44:49,360
Speaker 1: They were visually obscured in the terms of the study

773
00:44:49,880 --> 00:44:52,799
Speaker 1: and UH and so they were just operating off of

774
00:44:52,840 --> 00:44:55,480
Speaker 1: these pheromones that were put out by the females. And

775
00:44:55,520 --> 00:44:58,400
Speaker 1: what the study found is that for most of these

776
00:44:58,440 --> 00:45:01,720
Speaker 1: female mantis is the the rate at which the males

777
00:45:01,719 --> 00:45:04,759
Speaker 1: would approach them seemed to be indicating there was good

778
00:45:04,800 --> 00:45:08,080
Speaker 1: faith communication with the pheromones so males were most likely

779
00:45:08,160 --> 00:45:10,759
Speaker 1: to approach the good the you know, the ones who

780
00:45:10,760 --> 00:45:12,920
Speaker 1: had been on a good feeding schedule, and then a

781
00:45:12,920 --> 00:45:16,560
Speaker 1: little less likely to approach the ones on the medium

782
00:45:16,840 --> 00:45:19,799
Speaker 1: uh feeding schedule. So so there was a pretty much

783
00:45:19,840 --> 00:45:24,640
Speaker 1: correct advertisement system there except for one case, and that

784
00:45:24,760 --> 00:45:27,960
Speaker 1: one case that did not fit were the females who

785
00:45:28,040 --> 00:45:31,359
Speaker 1: had had the very poor feeding schedule, the ones who

786
00:45:31,400 --> 00:45:35,640
Speaker 1: got fed the worst, and those actually attracted more males

787
00:45:35,719 --> 00:45:39,960
Speaker 1: than any of the other female feeding regimens, even though

788
00:45:40,200 --> 00:45:42,720
Speaker 1: that meant the females were in the least good health

789
00:45:42,760 --> 00:45:45,840
Speaker 1: and they were the least likely to produce good numbers

790
00:45:45,880 --> 00:45:48,880
Speaker 1: of healthy offspring, but they were the most in need

791
00:45:48,960 --> 00:45:51,920
Speaker 1: of a good cannibal meal, right exactly, And so a

792
00:45:51,960 --> 00:45:55,040
Speaker 1: previous study had found that these females were more likely

793
00:45:55,080 --> 00:45:57,480
Speaker 1: to cannibalize males the ones who had had the least

794
00:45:57,560 --> 00:46:00,239
Speaker 1: eat So the hungry of the female is, the morely

795
00:46:00,320 --> 00:46:03,880
Speaker 1: she is to eat her mate. Now, studies necessarily or

796
00:46:04,040 --> 00:46:06,880
Speaker 1: have not necessarily found the same thing about other insects

797
00:46:06,920 --> 00:46:10,000
Speaker 1: and aragnets, but in this one particular species, it seems

798
00:46:10,040 --> 00:46:13,680
Speaker 1: that despite the fact that there's basically a correct or

799
00:46:13,800 --> 00:46:18,520
Speaker 1: good faith pheromone signaling system. UH, there are some cases

800
00:46:18,680 --> 00:46:22,799
Speaker 1: in which individuals will violate it in order to eat

801
00:46:22,880 --> 00:46:28,080
Speaker 1: somebody interact, so we get we get deception on top

802
00:46:28,160 --> 00:46:30,759
Speaker 1: of everything else that we're dealing with. You. Now, there's

803
00:46:30,800 --> 00:46:32,640
Speaker 1: one more paper I'd like to talk about that I

804
00:46:32,640 --> 00:46:36,759
Speaker 1: thought was pretty interesting. It's not directly addressing sexual cannibalism

805
00:46:36,760 --> 00:46:39,439
Speaker 1: as its main focus, but it had some cool observations

806
00:46:39,480 --> 00:46:43,960
Speaker 1: about it. And it's a paper called conditional monogamy Female

807
00:46:44,000 --> 00:46:47,319
Speaker 1: Quality predicts Male Faithfulness and it was published in Frontiers

808
00:46:47,320 --> 00:46:51,480
Speaker 1: in Zoology in So the premise of this paper is

809
00:46:51,520 --> 00:46:55,960
Speaker 1: that males from lots of animal species display polygony, you know,

810
00:46:56,320 --> 00:46:59,480
Speaker 1: having lots of wives, mating with more than one female,

811
00:46:59,800 --> 00:47:02,799
Speaker 1: you really as many females as he can. But some

812
00:47:02,880 --> 00:47:06,520
Speaker 1: animal species display I guess the inverse of that monogamy,

813
00:47:06,520 --> 00:47:09,840
Speaker 1: wherein the male only mates with one female in his

814
00:47:10,080 --> 00:47:13,239
Speaker 1: entire lifetime. Now, this might be for multiple reasons. The

815
00:47:13,280 --> 00:47:17,160
Speaker 1: male might be involved in uh, for for example, parent

816
00:47:17,200 --> 00:47:21,479
Speaker 1: parental duties maybe, but there there are some species where

817
00:47:21,520 --> 00:47:23,560
Speaker 1: that doesn't really seem to be the case yet there

818
00:47:23,640 --> 00:47:26,960
Speaker 1: is still just mating with one female in the lifetime.

819
00:47:27,360 --> 00:47:30,920
Speaker 1: And this would include especially to interest to our interests

820
00:47:31,000 --> 00:47:34,400
Speaker 1: several species of spiders. Now that this is a quote

821
00:47:34,480 --> 00:47:38,839
Speaker 1: from the paper monogamy is associated with curious adaptations like

822
00:47:39,280 --> 00:47:42,719
Speaker 1: lifelong associations between males and females. I like, how that's

823
00:47:42,719 --> 00:47:49,200
Speaker 1: a curious adaptation, but also extreme sexual size dimorphism, genital damage,

824
00:47:49,400 --> 00:47:52,320
Speaker 1: and sexual cannibalism. Okay, so that just lays out the

825
00:47:52,360 --> 00:47:55,359
Speaker 1: obvious that sometimes you meet that special person and that's

826
00:47:55,360 --> 00:47:57,080
Speaker 1: the only person you want to be with for the

827
00:47:57,120 --> 00:47:59,560
Speaker 1: rest of your life. Other times they kill you and

828
00:47:59,640 --> 00:48:02,880
Speaker 1: eat you or damage your genitals. Yeah. So, uh so, Now,

829
00:48:02,920 --> 00:48:05,520
Speaker 1: if you look at a male spiders sex organs on

830
00:48:05,640 --> 00:48:08,280
Speaker 1: one thing you might see is that the male spider

831
00:48:08,280 --> 00:48:12,080
Speaker 1: has these two copulatory organs called the pet a palps

832
00:48:12,080 --> 00:48:14,799
Speaker 1: that are used for copulation. These are sort of like

833
00:48:14,920 --> 00:48:18,960
Speaker 1: miniature arms coming out of the spider's head. Also, it

834
00:48:19,080 --> 00:48:22,280
Speaker 1: is likely that these organs will be damaged in mating.

835
00:48:22,719 --> 00:48:27,319
Speaker 1: So essentially, the male spider has two detachable penises available

836
00:48:27,400 --> 00:48:30,879
Speaker 1: for his mating budget and the females, on the other hand,

837
00:48:30,920 --> 00:48:34,600
Speaker 1: can mate multiple times. So the female spider has a

838
00:48:34,640 --> 00:48:38,640
Speaker 1: pair of incimination ducts. These are her her mating openings

839
00:48:38,680 --> 00:48:41,520
Speaker 1: and these can be in a sense plugged by a

840
00:48:41,680 --> 00:48:47,200
Speaker 1: broken off piece of male spider copulatory organs sense, so

841
00:48:47,440 --> 00:48:49,360
Speaker 1: he can break off part of his pet a palp

842
00:48:49,920 --> 00:48:54,640
Speaker 1: in her incimination duct to prevent other male rivals from

843
00:48:54,680 --> 00:48:58,279
Speaker 1: successfully coming along and mating with that same female, like

844
00:48:58,320 --> 00:49:01,360
Speaker 1: a stabbing in a Cormack McArthur novel where they snapped

845
00:49:01,360 --> 00:49:04,560
Speaker 1: the blade off in the wound. Yeah. Yeah, it sounds

846
00:49:04,600 --> 00:49:07,520
Speaker 1: pretty violent in our terms, but but I guess this

847
00:49:07,600 --> 00:49:10,839
Speaker 1: is how the spiders work. We we shall not judge now.

848
00:49:10,840 --> 00:49:13,120
Speaker 1: The study in particular is focused on the orb web

849
00:49:13,160 --> 00:49:16,040
Speaker 1: spider known as the wasps spider or our guy a

850
00:49:16,160 --> 00:49:21,040
Speaker 1: pee bruiniqui, and a few mating stats from previous research show.

851
00:49:21,120 --> 00:49:24,360
Speaker 1: One is that in the laboratory, females are quote highly

852
00:49:24,400 --> 00:49:28,239
Speaker 1: cannibalistic and eighty percent of males are killed during their

853
00:49:28,280 --> 00:49:31,480
Speaker 1: first copulation. That's a lot pretty high. Yeah yeah. They

854
00:49:31,520 --> 00:49:35,839
Speaker 1: also say genital damage is very common in a bruin bruiniqui,

855
00:49:36,200 --> 00:49:39,560
Speaker 1: and it occurs in eighty five percent of copulations into

856
00:49:39,719 --> 00:49:43,000
Speaker 1: unused genital openings. So there's a really good chance that

857
00:49:43,120 --> 00:49:46,360
Speaker 1: you get your sexual organ broken off inside the female.

858
00:49:47,239 --> 00:49:49,200
Speaker 1: And then on top of that, they say the broken

859
00:49:49,200 --> 00:49:52,480
Speaker 1: off pieces remain in the female insemination duc to nine

860
00:49:53,040 --> 00:49:55,480
Speaker 1: percent of these cases, so that these things, when they

861
00:49:55,480 --> 00:49:59,320
Speaker 1: get broken off, are highly effective in plugging the hole

862
00:49:59,440 --> 00:50:02,080
Speaker 1: so that other males can't come along and mate with

863
00:50:02,080 --> 00:50:06,640
Speaker 1: the same female. So that's one positive reason for detaching

864
00:50:06,880 --> 00:50:12,759
Speaker 1: one's penis. Y yeah, among others, I assume. Uh no,

865
00:50:12,840 --> 00:50:16,760
Speaker 1: I bet that's the only one that may be. But anyway,

866
00:50:16,800 --> 00:50:19,640
Speaker 1: so since the male sex organs tend to get broken off,

867
00:50:19,840 --> 00:50:21,800
Speaker 1: he has a choice. He has two of these things,

868
00:50:22,280 --> 00:50:25,520
Speaker 1: and he can spend them both on the same female.

869
00:50:26,360 --> 00:50:29,359
Speaker 1: This would be the case of monogamy, mating with only

870
00:50:29,400 --> 00:50:31,840
Speaker 1: one female in his lifetime, or he can try to

871
00:50:31,880 --> 00:50:34,759
Speaker 1: mate with two different females in his lifetime. Okay, so

872
00:50:34,840 --> 00:50:38,120
Speaker 1: we see us a form of mate selection here that

873
00:50:38,520 --> 00:50:41,759
Speaker 1: he can decide if this is definitely the one so

874
00:50:41,840 --> 00:50:43,480
Speaker 1: much so that he wants to double down on this

875
00:50:43,560 --> 00:50:47,160
Speaker 1: mate selection, or if he wants to save one keep

876
00:50:47,160 --> 00:50:49,560
Speaker 1: one in a chamber for labor later used. Right, It's

877
00:50:49,560 --> 00:50:51,880
Speaker 1: like if you're you know, you know, you're you're playing

878
00:50:51,960 --> 00:50:53,879
Speaker 1: roulette and you have two chips. Do you put them

879
00:50:53,880 --> 00:50:55,839
Speaker 1: on two different numbers or do you put them both

880
00:50:55,880 --> 00:50:58,399
Speaker 1: on the same number? All in on Black Widow right.

881
00:50:59,040 --> 00:51:02,239
Speaker 1: So the researchers tested interactions between these fighters, and they

882
00:51:02,239 --> 00:51:05,520
Speaker 1: found lots of interesting correlations. For example, the size of

883
00:51:05,560 --> 00:51:08,040
Speaker 1: the male did not seem to have any impact on

884
00:51:08,080 --> 00:51:11,640
Speaker 1: the mating strategy, but the size of the female did so.

885
00:51:12,080 --> 00:51:14,840
Speaker 1: When when a male encountered a female for the first time,

886
00:51:15,320 --> 00:51:18,520
Speaker 1: the bigger the female, the more likely the male was

887
00:51:18,600 --> 00:51:21,600
Speaker 1: to use his entire mating budget on her to give

888
00:51:21,600 --> 00:51:25,160
Speaker 1: her both of his sex organs. Also, when a male

889
00:51:25,239 --> 00:51:27,920
Speaker 1: mated with two different females, when he decided to spread

890
00:51:27,920 --> 00:51:31,879
Speaker 1: it over two different two different numbers on roulette, the

891
00:51:31,960 --> 00:51:35,240
Speaker 1: second female he broke off a sex organ with tended

892
00:51:35,280 --> 00:51:37,880
Speaker 1: to be heavier than the first, so he would tend

893
00:51:37,920 --> 00:51:41,640
Speaker 1: to trade up for a larger female. The larger the

894
00:51:41,640 --> 00:51:44,680
Speaker 1: female usually the more fecand well like a lot of

895
00:51:44,719 --> 00:51:46,640
Speaker 1: what we've discussed here in this episode, and that that

896
00:51:46,680 --> 00:51:50,399
Speaker 1: makes perfect economic sense, of course. Now a few other

897
00:51:50,480 --> 00:51:52,440
Speaker 1: interesting things they observed. One of them was that the

898
00:51:52,560 --> 00:51:55,560
Speaker 1: rate of sexual cannibalism they saw in their study was

899
00:51:55,640 --> 00:51:59,080
Speaker 1: much lower than what had been previously reported that number

900
00:51:59,080 --> 00:52:02,920
Speaker 1: we cited earlier. They found that the frequency of cannibalism

901
00:52:02,960 --> 00:52:05,920
Speaker 1: on the first copulation. So the first time male and

902
00:52:05,960 --> 00:52:10,239
Speaker 1: female meet up was thirty one point four percent, so

903
00:52:10,440 --> 00:52:13,760
Speaker 1: that's lower than than previous studies. But there was also

904
00:52:13,840 --> 00:52:16,759
Speaker 1: one really funny complication of how this worked out. In

905
00:52:16,760 --> 00:52:21,160
Speaker 1: the lab, they write, quote, the monogamous males either copulated

906
00:52:21,239 --> 00:52:23,520
Speaker 1: once in one and this is what they called the

907
00:52:23,520 --> 00:52:27,520
Speaker 1: group m one um, which are males cannibalized after a

908
00:52:27,600 --> 00:52:31,960
Speaker 1: single copulation or twice with the same female. In the

909
00:52:32,120 --> 00:52:34,879
Speaker 1: M one group, it cannot be decided whether males would

910
00:52:34,880 --> 00:52:38,920
Speaker 1: have followed a bigginess or monogamous tactic if only they

911
00:52:38,920 --> 00:52:43,239
Speaker 1: had survived their first copulation. So sometimes the male he

912
00:52:43,320 --> 00:52:46,719
Speaker 1: gets one broken off sex organ into the female, but

913
00:52:46,800 --> 00:52:49,360
Speaker 1: then she eats him and you can't tell whether he

914
00:52:49,480 --> 00:52:52,080
Speaker 1: was planning on using both on her or moving on.

915
00:52:53,040 --> 00:52:56,440
Speaker 1: That's right, because she has enacted her a mating choice

916
00:52:56,640 --> 00:53:00,319
Speaker 1: exactly he can exercise h Yeah. And and related to

917
00:53:00,400 --> 00:53:02,680
Speaker 1: that is that one thing they noticed was I think

918
00:53:02,760 --> 00:53:04,680
Speaker 1: this goes along with some of the other stuff we've read.

919
00:53:04,880 --> 00:53:07,640
Speaker 1: How long a male mate it during his first copulation

920
00:53:07,760 --> 00:53:11,560
Speaker 1: was directly positively correlated to the rate of sexual cannibalism.

921
00:53:11,719 --> 00:53:14,200
Speaker 1: So the longer he sticks around, the more time he

922
00:53:14,280 --> 00:53:17,759
Speaker 1: spends locking down his copulation with this one female, the

923
00:53:17,840 --> 00:53:21,600
Speaker 1: higher the chance that he gets slain and devoured. All right, now,

924
00:53:21,640 --> 00:53:24,120
Speaker 1: I want to read one more long ish quote from

925
00:53:24,120 --> 00:53:26,560
Speaker 1: their discussion section because I thought it was really interesting

926
00:53:26,600 --> 00:53:30,120
Speaker 1: related to what we've been talking about today. They say, quote,

927
00:53:30,480 --> 00:53:34,759
Speaker 1: some of the monogamous males were cannibalized after their first copulation,

928
00:53:34,880 --> 00:53:37,960
Speaker 1: while others used both of their mating options with the

929
00:53:38,000 --> 00:53:41,560
Speaker 1: same female. While the latter can be interpreted as a

930
00:53:41,600 --> 00:53:45,280
Speaker 1: clear cut male decision. So if the male uses both

931
00:53:45,400 --> 00:53:48,080
Speaker 1: on the female and then gets eaten, sort of makes

932
00:53:48,080 --> 00:53:52,080
Speaker 1: sense for him to get eaten. Um Uh. They picked

933
00:53:52,080 --> 00:53:55,719
Speaker 1: back up. Interpreting the decisions of single mated males is

934
00:53:55,800 --> 00:53:58,759
Speaker 1: more difficult. At least, some of these males may have

935
00:53:58,840 --> 00:54:02,839
Speaker 1: been forced into anogamy by aggressive females, while others may

936
00:54:02,840 --> 00:54:06,400
Speaker 1: have chosen to sacrifice themselves to their mating partner already

937
00:54:06,760 --> 00:54:10,320
Speaker 1: during the first copulation. Whether a male falls victim to

938
00:54:10,400 --> 00:54:14,360
Speaker 1: sexual cannibalism during the first copulation is a direct function

939
00:54:14,440 --> 00:54:18,840
Speaker 1: of its duration. Any copulation longer than ten seconds, remember

940
00:54:18,880 --> 00:54:23,160
Speaker 1: that number will most likely end with the death of

941
00:54:23,200 --> 00:54:26,320
Speaker 1: the males. Well, males that jump off before ten seconds

942
00:54:26,560 --> 00:54:31,200
Speaker 1: have a relatively high chance of surviving. Indeed, copulation durations

943
00:54:31,239 --> 00:54:34,520
Speaker 1: of single mated males show a high variance, which suggests

944
00:54:34,560 --> 00:54:37,680
Speaker 1: that some of them chose to copulate for longer in

945
00:54:37,800 --> 00:54:42,040
Speaker 1: spite of sexual cannibalism being the likely consequence, while others

946
00:54:42,040 --> 00:54:47,560
Speaker 1: attempted to escape but failed. So, I don't know, I

947
00:54:47,600 --> 00:54:49,960
Speaker 1: feel like that sort of drives home that when you're

948
00:54:49,960 --> 00:54:53,000
Speaker 1: speaking about evolution, it's worth remembering that your body is

949
00:54:53,040 --> 00:54:55,520
Speaker 1: sort of of little use to your genes once you've

950
00:54:55,560 --> 00:54:59,080
Speaker 1: lost all of your reproductive potential. Yes, the male individual

951
00:54:59,160 --> 00:55:02,600
Speaker 1: here is is the delivery system for the genetic material.

952
00:55:02,880 --> 00:55:05,399
Speaker 1: But anyway, if you want to read that study, it's

953
00:55:05,400 --> 00:55:09,920
Speaker 1: again conditional monogamy, female quality predicts male faithfulness. It's pretty

954
00:55:09,960 --> 00:55:12,880
Speaker 1: interesting and had some other observations too. All right, so

955
00:55:12,880 --> 00:55:17,080
Speaker 1: there you have it. Uh, we've we've discussed sexual cannibalism,

956
00:55:17,160 --> 00:55:21,360
Speaker 1: some of the theories regarding uh, it's the evolutionary development

957
00:55:21,600 --> 00:55:23,799
Speaker 1: a handful of species why it seems like it might

958
00:55:23,840 --> 00:55:27,319
Speaker 1: not make sense, but but it probably does. And of

959
00:55:27,360 --> 00:55:30,040
Speaker 1: course we've engaged in a fair amount of anthromomorphism. But

960
00:55:30,480 --> 00:55:32,360
Speaker 1: still I felt like I was holding back in some

961
00:55:32,480 --> 00:55:35,719
Speaker 1: of these, So was I Now, if you're a professional

962
00:55:35,760 --> 00:55:38,160
Speaker 1: researcher in this field, don't take a page from us,

963
00:55:38,560 --> 00:55:41,920
Speaker 1: try to do do the right thing, be boring, but

964
00:55:42,040 --> 00:55:45,320
Speaker 1: be accurate, and think like an insect than ever possible.

965
00:55:46,080 --> 00:55:47,719
Speaker 1: All Right. In the meantime, if you want to check

966
00:55:47,719 --> 00:55:49,600
Speaker 1: out more episodes of Stuff to Blow your Mind, head

967
00:55:49,600 --> 00:55:52,600
Speaker 1: on over to our website that's the mothership stuff to

968
00:55:52,640 --> 00:55:54,400
Speaker 1: Blow your Mind dot com, where you'll find all the

969
00:55:54,440 --> 00:55:57,520
Speaker 1: podcast episodes, videos, blog post links out to our social

970
00:55:57,520 --> 00:56:00,360
Speaker 1: media accounts such as Facebook and Twitter. We're blow the

971
00:56:00,360 --> 00:56:02,319
Speaker 1: Mind on both of those. We are Stuff to Blow

972
00:56:02,360 --> 00:56:04,359
Speaker 1: your Mind on Tumbler. And if you want to get

973
00:56:04,400 --> 00:56:06,920
Speaker 1: in touch with us with feedback about this episode or

974
00:56:06,920 --> 00:56:10,040
Speaker 1: any interesting facts you've ever learned about sexual cannibalism, you

975
00:56:10,040 --> 00:56:13,000
Speaker 1: can email us at blow the Mind at how stuff

976
00:56:13,000 --> 00:56:24,440
Speaker 1: works dot com for more on this and thousands of

977
00:56:24,480 --> 00:56:49,560
Speaker 1: other topics. Is it how stuff works dot com