WEBVTT - Leeches (featuring Dr. Anna Phillips) 0:00:05.960 --> 0:00:10.399 When most people think of leeches, they're immediately disgusted, or 0:00:10.400 --> 0:00:12.360 at least that's been my experience when I talk to 0:00:12.360 --> 0:00:15.880 people about leeches. But what is it about leeches that 0:00:16.160 --> 0:00:18.680 results in so much more disgust than we feel when 0:00:18.680 --> 0:00:22.239 we talk about other blood suckers like mosquitoes. Maybe it's 0:00:22.280 --> 0:00:24.800 that scene from Stand By Me or that scene from 0:00:24.880 --> 0:00:29.800 African Queen, or maybe it's something else altogether. And look, today, 0:00:30.160 --> 0:00:32.120 I'm sure we're not going to convince most of you 0:00:32.479 --> 0:00:35.519 that leeches are beautiful. But I hope that when you 0:00:35.600 --> 0:00:38.199 listen to this episode, Anna and I are able to 0:00:38.240 --> 0:00:41.720 convince you that leeches are Okay, fine, maybe they're disgusting, 0:00:41.760 --> 0:00:45.199 but they're all so fascinating and maybe they're even helpful 0:00:45.280 --> 0:00:48.240 to people. So, for example, you know, maybe you've heard 0:00:48.320 --> 0:00:50.800 that leeches used to be used to try to draw 0:00:50.880 --> 0:00:54.000 blood to treat just about any problem that humans used 0:00:54.000 --> 0:00:56.160 to have a long time ago, But did you know 0:00:56.800 --> 0:01:00.200 that leeches are still used in particular medical cases and 0:01:00.240 --> 0:01:04.200 they're actually helpful, and that leeches produce anti coagulants, which 0:01:04.200 --> 0:01:06.440 are these chemicals that make sure your blood doesn't clot 0:01:06.560 --> 0:01:09.880 up that are useful in a variety of medical settings, 0:01:10.200 --> 0:01:14.120 so understanding leeches can be helpful for human health as well. 0:01:14.720 --> 0:01:18.039 On today's episode, we have doctor Anna Phillips, who's the 0:01:18.120 --> 0:01:21.839 curator of earthworms and parasitic worms at the Smithsonian Natural 0:01:21.880 --> 0:01:24.640 History Museum in Washington, d C. And I can't think 0:01:24.640 --> 0:01:27.480 of a better person to talk to us today about leeches. 0:01:28.040 --> 0:01:32.040 So welcome to Daniel and Kelly's extraordinary and sometimes a 0:01:32.040 --> 0:01:33.880 little bit disgusting universe. 0:01:47.960 --> 0:01:50.440 Hi. I'm Daniel. I'm a particle physicist, and I've never 0:01:50.480 --> 0:01:51.760 been bitten by a particle. 0:01:52.320 --> 0:01:52.480 Hi. 0:01:52.840 --> 0:01:56.360 I'm Kelly Wienersmith. I'm a parasitologist and I've been bitten 0:01:56.360 --> 0:01:59.680 by leeches and it was okay, it was fine. 0:02:00.240 --> 0:02:04.600 Ends clearly they've infected you with some sort of brain 0:02:04.680 --> 0:02:06.840 disease that made you think it was okay. 0:02:06.920 --> 0:02:09.560 You know, we're gonna learn today the surprisingly they don't 0:02:09.680 --> 0:02:12.320 vector a lot of diseases. I'm like mosquitoes and ticks, 0:02:12.560 --> 0:02:15.760 they're not so bad. They're just hungry, which I get. 0:02:16.080 --> 0:02:18.680 I get that you've been brainwashed, you've been leech washed 0:02:18.720 --> 0:02:22.000 by leeches. I am not okay with being bitten by leeches. 0:02:22.080 --> 0:02:24.839 Well, I'm hoping that we can leech wash at least 0:02:24.880 --> 0:02:27.359 a few of our listeners today into thinking that leeches 0:02:27.360 --> 0:02:30.480 are maybe still gross, but that there's absolutely some fascinating 0:02:30.480 --> 0:02:31.519 stuff to learn from them. 0:02:31.720 --> 0:02:33.720 All right, well, then my question for you today, Kelly, 0:02:33.840 --> 0:02:36.919 is what is the grossest thing you have been bitten by? 0:02:37.400 --> 0:02:40.480 Oh? Gosh, the grossest thing I've been bitten by? I 0:02:40.480 --> 0:02:41.960 guess that's gotta be ticks. 0:02:42.400 --> 0:02:43.239 Ticks are the worst. 0:02:43.320 --> 0:02:47.600 I hate ticks. I really hate ticks. Like leeches. I'm 0:02:47.639 --> 0:02:49.680 okay with ticks, man, I hate them. You know. So 0:02:49.760 --> 0:02:52.040 you get a take, you pull it off, and you're like, oh, well, 0:02:52.040 --> 0:02:53.800 now should I send it in for testing? Do I 0:02:53.840 --> 0:02:56.160 have to worry that I got lime disease? What about 0:02:56.280 --> 0:02:59.080 you know, Rocky Mountain spotted fever? And whereas if you 0:02:59.080 --> 0:03:01.480 get bit by a leech, just like, oh I'm bleeding 0:03:01.520 --> 0:03:03.840 a little. That stinks, but you don't worry about what's 0:03:03.840 --> 0:03:06.320 going to happen afterwards, like that's the end of the encounter. 0:03:06.760 --> 0:03:08.359 And I get bit by ticks pretty often and it 0:03:08.400 --> 0:03:10.440 kind of freaks me out. I regularly spray my clothes 0:03:10.480 --> 0:03:12.480 with permethrin during the summer when I'm going to be 0:03:12.520 --> 0:03:14.320 going out in the woods, and like every member of 0:03:14.320 --> 0:03:18.079 our family has a set of permethrin treated clothes that 0:03:18.120 --> 0:03:19.680 they wear if they're going to be going out into 0:03:19.680 --> 0:03:21.640 the woods, because we've already had some lime in the 0:03:21.680 --> 0:03:24.280 family and we don't want anymore. What about you, what's 0:03:24.320 --> 0:03:26.520 the weirdest or gressest thing you've ever been bitten by? 0:03:26.680 --> 0:03:27.399 Not a particle. 0:03:29.360 --> 0:03:31.640 I was bitten by our pet rats once, so I 0:03:31.680 --> 0:03:35.000 have had a rat bite, and in their defense, my 0:03:35.040 --> 0:03:37.120 finger was covered with whipped cream and I stuck it 0:03:37.120 --> 0:03:39.920 in the cage and they got very enthusiastic. I don't 0:03:39.920 --> 0:03:42.000 think they were trying to bite my finger, but you know, 0:03:42.160 --> 0:03:44.000 how could you control yourself? It's whipped cream. 0:03:44.160 --> 0:03:46.800 I get it. I'm sorry. I understand the rats in 0:03:46.840 --> 0:03:49.440 that case. I've also been bit by a boa constrictor 0:03:49.840 --> 0:03:51.800 when I went to feed it a rat and I 0:03:51.840 --> 0:03:53.800 wasn't really careful about what I was doing with my hand. 0:03:54.080 --> 0:03:56.400 And then I also got bit once by an alligator 0:03:56.400 --> 0:03:57.680 gar Have you seen these? 0:03:58.240 --> 0:03:59.480 Is that like an alligator. 0:03:59.560 --> 0:04:02.680 It's a fit with an alligator like mouth. They're common 0:04:02.920 --> 0:04:05.040 in the South, but there's also some in Lake Eerie 0:04:05.120 --> 0:04:07.000 and I was doing a fish survey and I thought 0:04:07.000 --> 0:04:09.320 one had passed away, but even though it was very dry, 0:04:09.400 --> 0:04:11.240 it was still kicking. So I grabbed it by the 0:04:11.280 --> 0:04:14.080 tail and it turned around, and I was like, ah, 0:04:14.120 --> 0:04:14.520 I'm so. 0:04:14.560 --> 0:04:17.680 Sorry it's biting you and you're apologizing to it. Wow, 0:04:17.680 --> 0:04:18.360 you're so polite. 0:04:18.440 --> 0:04:20.800 I mean, if I were on the way out and 0:04:20.880 --> 0:04:23.440 somebody was harassing me, I would be grumpy about that too. 0:04:23.560 --> 0:04:25.800 I understood where it was coming from, but yeah, sorry. 0:04:25.800 --> 0:04:27.719 Your story reminded me of some of my other stories 0:04:27.720 --> 0:04:28.800 that how could I have forgotten? 0:04:28.960 --> 0:04:31.680 Well, your comment earlier about not being too grumpy about 0:04:31.680 --> 0:04:35.039 giving blood to leeches made me think about mosquitoes, because 0:04:35.320 --> 0:04:39.280 we recently had mosquitoes basically taking over southern California. When 0:04:39.279 --> 0:04:42.279 I moved here twenty years ago, there were almost no mosquitoes, 0:04:42.320 --> 0:04:45.960 and how their mosquitoes everywhere drives me crazy because I 0:04:46.000 --> 0:04:47.919 would happily give up a little bit of blood to 0:04:47.960 --> 0:04:51.800 mosquitoes if they didn't deposit the anesthetic that you then 0:04:51.880 --> 0:04:54.560 react to like it frustrates me endlessly. I would like 0:04:54.600 --> 0:04:56.880 set out a little pool of blood, you know, for 0:04:56.920 --> 0:04:58.839 them every day. If we could strike a deal with 0:04:58.920 --> 0:05:02.760 mosquitoes like stop giving me bites and drink my blood, 0:05:02.800 --> 0:05:05.400 I would happily give up blood to avoid mosquito bites. 0:05:05.440 --> 0:05:07.520 Oh, man, only we could have like a doctor Doolittle. 0:05:07.600 --> 0:05:09.839 But who could communicate with the mosquitos to set that 0:05:09.920 --> 0:05:12.279 kind of exchange up? That would be ideal. Why do 0:05:12.320 --> 0:05:14.320 you have so many more mosquitos? Has a new species 0:05:14.360 --> 0:05:16.960 moved in? Is it wetter? With more standing pools of water? 0:05:17.080 --> 0:05:17.720 Would change? 0:05:18.040 --> 0:05:20.600 I read this story once that claimed that they all 0:05:20.680 --> 0:05:24.840 came in one shipping container to Long Beach from China 0:05:24.880 --> 0:05:27.440 and they basically took over like it was a huge 0:05:27.480 --> 0:05:31.240 invasion of this Chinese tiny mosquito, not like the big 0:05:31.279 --> 0:05:34.279 American mosquitoes, but these little ones that also bite you 0:05:34.360 --> 0:05:36.279 multiple times, so you don't just get like one bite, 0:05:36.279 --> 0:05:38.880 you could like a series of bites. Oh really, not 0:05:38.960 --> 0:05:39.240 a fan? 0:05:39.320 --> 0:05:39.480 Wait? 0:05:39.480 --> 0:05:42.840 Why was China shipping us mosquitoes? They just accidentally got 0:05:42.880 --> 0:05:44.640 into a shipment? Is that the deal? 0:05:44.880 --> 0:05:48.160 Or somebody ordered mosquitos on Amazon and now we're all suffering? 0:05:48.320 --> 0:05:48.360 No? 0:05:48.480 --> 0:05:50.120 I think it was an accident. Yeah, there was some 0:05:50.160 --> 0:05:53.200 pool standing water in this shipping container and they survived 0:05:53.200 --> 0:05:55.360 the transit and they opened it up in Long Beach. 0:05:55.480 --> 0:05:57.120 Dot dot dot. My life is now terrible. 0:05:57.200 --> 0:06:00.000 That's the worst. I'm sorry. We've got an Asian longhorn 0:06:00.080 --> 0:06:03.159 and tick, which I think also accidentally got here, and 0:06:03.200 --> 0:06:05.800 it can reproduce without finding a mate. You get one, 0:06:05.839 --> 0:06:07.680 and then you've got ten, and then you've got hundreds. 0:06:07.720 --> 0:06:12.039 And there are cattle out here that are getting like exsanguinated. 0:06:12.240 --> 0:06:14.159 If they're not checked on regularly enough, they end up 0:06:14.160 --> 0:06:15.720 getting tons of them and then they don't have enough 0:06:15.720 --> 0:06:16.880 blood to do what they need to do. 0:06:16.960 --> 0:06:20.920 So anyway, exanguinated, my mental image is that you go 0:06:20.960 --> 0:06:22.840 out to check on your cow and it's just like 0:06:22.880 --> 0:06:24.920 a dry heap of skin and bones. Is that what 0:06:24.920 --> 0:06:25.560 we're talking about. 0:06:25.680 --> 0:06:28.160 I think they die before they look how you might 0:06:28.160 --> 0:06:30.719 imagine Dracula looks waking up in the morning. But yeah, 0:06:30.760 --> 0:06:32.599 I mean the dying from lack of blood. And I 0:06:32.600 --> 0:06:35.640 think there's some concern that there's a hemorrhagic fever in 0:06:35.680 --> 0:06:38.560 the native area that like could jump to here and 0:06:38.600 --> 0:06:40.480 now instead of in addition to lime, you'd have to 0:06:40.480 --> 0:06:43.359 worry about hemorrhagic fevers. And anyway, it's so great that 0:06:43.400 --> 0:06:45.680 we can ship stuff around the world, but it's got 0:06:45.720 --> 0:06:47.000 its downsides. 0:06:48.279 --> 0:06:50.560 All right, Well, today we're not just talking about what 0:06:50.680 --> 0:06:52.680 Daniel doesn't like to be bitten by, and what Kelly 0:06:52.720 --> 0:06:55.520 doesn't mind being bitten by. We're talking about all the 0:06:55.600 --> 0:06:57.920 exciting signs behind leeches. 0:06:57.920 --> 0:07:01.520 And so we asked you what is the first thing 0:07:01.600 --> 0:07:05.080 you think when you think of leeches? And I got 0:07:05.120 --> 0:07:07.080 to say, I got a couple answers that I expected, 0:07:07.120 --> 0:07:10.000 a couple that were very unexpected. And if you would 0:07:10.040 --> 0:07:11.960 like to be asked what you think about a topic 0:07:12.000 --> 0:07:14.280 we're going to talk about on the show, email us 0:07:14.360 --> 0:07:17.560 at questions at Daniel and Kelly dot org. So let's 0:07:17.560 --> 0:07:18.960 hear what our listeners had to say. 0:07:19.480 --> 0:07:23.360 A picture that I've seen of a black hole eating 0:07:23.400 --> 0:07:25.840 the material from a closely orbiting star. 0:07:26.560 --> 0:07:29.120 Honestly, they're just the wist and I can't think of 0:07:29.160 --> 0:07:32.520 anything more disgusting. The first thing I think of is 0:07:32.760 --> 0:07:38.520 medical grade leeches that are used to drain blood from hematomas, 0:07:39.000 --> 0:07:41.520 bruises under the skin that have a lot of blood 0:07:41.560 --> 0:07:42.040 in them. 0:07:42.280 --> 0:07:44.640 The first thing I think of when I hear leeches 0:07:45.320 --> 0:07:48.480 is traveling down the Brasis River in Texas on a 0:07:48.520 --> 0:07:52.400 boy scout trip and on an inner tube and coming 0:07:52.400 --> 0:07:55.760 out with leeches stuck to the inner tube and a 0:07:55.760 --> 0:07:57.600 few to my legs. No fun. 0:07:58.040 --> 0:08:01.240 Watching the movie The African Queen with Katherine Hepburn and 0:08:01.360 --> 0:08:04.320 Humphrey Bogart, and they have to tow his boat through 0:08:04.320 --> 0:08:07.640 the swamp, waiting in the swamp, and when they get 0:08:07.680 --> 0:08:10.880 out there covered with leeches, and they have to spread 0:08:10.960 --> 0:08:12.600 salt on the leeches to get them off. 0:08:13.040 --> 0:08:18.600 Medieval medical practices where they were used for almost everything 0:08:19.080 --> 0:08:24.400 from headaches to ingrown toenails. I don't know conjunct to 0:08:24.440 --> 0:08:28.880 fight us not all it being one of Dracula's favorite pets. 0:08:29.320 --> 0:08:32.600 They've seen and stand by Me where they're swimming across 0:08:32.600 --> 0:08:36.240 the swamp and they suddenly discover that they're covered in leeches. 0:08:36.840 --> 0:08:38.480 I think of the movie stand by Me. 0:08:38.960 --> 0:08:42.439 Wasn't there an old black and white movie called Attack 0:08:42.480 --> 0:08:43.120 of Leeches? 0:08:43.320 --> 0:08:45.520 Or something seen from stand by Me? 0:08:46.440 --> 0:08:49.160 The third thing that comes to mind is the irs. 0:08:49.679 --> 0:08:51.439 I think of the way they ribed and twisted. 0:08:51.480 --> 0:08:53.560 When I discovered them as a kid, I thought it 0:08:53.600 --> 0:08:55.480 was swimming around my finger in a strange way. 0:08:55.800 --> 0:08:57.760 Then I pictured my mom screaming. 0:08:57.440 --> 0:09:02.160 The barber surgeon from the Middle Ages applying them meditionally 0:09:02.240 --> 0:09:03.080 up with that in quotes. 0:09:03.679 --> 0:09:06.719 So I love that. The very first answer that hit 0:09:06.800 --> 0:09:09.800 my inbox was a picture that I've seen of a 0:09:09.840 --> 0:09:12.600 black hole eating the material from a closely orbiting star. 0:09:12.720 --> 0:09:15.440 I was like, Wow, in my world, that is not 0:09:15.679 --> 0:09:17.640 what you would expect the answer to be. But like, 0:09:18.000 --> 0:09:20.679 I see that, that's a fascinating answer. That was great. 0:09:20.960 --> 0:09:23.520 That's our audience right there. Physics biology crossover. 0:09:23.679 --> 0:09:26.440 Yeah, it's amazing. And then most of the other responses 0:09:26.480 --> 0:09:28.959 were like I expected people to mention stand by me, 0:09:29.600 --> 0:09:32.400 and I expected people to mention that one movie with 0:09:32.480 --> 0:09:35.240 Catherine Hepburn African Queen I think it was, and then 0:09:35.280 --> 0:09:38.320 mostly to be grossed out. And so that was more 0:09:38.400 --> 0:09:40.600 or less what I was expecting. What did you think? 0:09:40.760 --> 0:09:44.480 Yeah, these answers basically mimic my thoughts about leeches. I'm 0:09:44.520 --> 0:09:47.360 totally uninformed. I don't know anything about leeches compared to 0:09:47.360 --> 0:09:50.000 anything else except that I'm grossed out with anything bites me. 0:09:50.320 --> 0:09:52.800 So I'm curious to learn what is the science of leeches, 0:09:53.120 --> 0:09:57.480 what are leech scientists leechologists working on. What motivates somebody 0:09:57.559 --> 0:10:00.920 to get into leeches anyway, rather than basic any other 0:10:01.040 --> 0:10:04.200 field of science. So yeah, I want to meet your 0:10:04.200 --> 0:10:06.000 friend and hear all about leeches. 0:10:06.160 --> 0:10:07.560 Wait, wait, so would you say that this is at 0:10:07.600 --> 0:10:09.880 the bottom of the list of science jobs you would 0:10:09.880 --> 0:10:11.240 want studying leeches. 0:10:11.840 --> 0:10:14.280 It's not near the top, that's for sure. I wouldn't 0:10:14.320 --> 0:10:17.840 put it in the top fifty or one thousand science jobs. 0:10:17.920 --> 0:10:20.000 I mean, I think I'm pretty capable of getting interested 0:10:20.040 --> 0:10:22.640 in almost anything, but yeah, this is a bit of 0:10:22.679 --> 0:10:23.760 a gross out factor for me. 0:10:24.080 --> 0:10:26.240 I gotta say, if somebody said you could be the 0:10:26.360 --> 0:10:30.080 leech person at the Smithsonian Museum, I'd be like, I 0:10:30.200 --> 0:10:32.679 enjoyed studying space, but I'm studying leeches now, and I 0:10:32.720 --> 0:10:35.400 would make that jump. All right, So today we are 0:10:35.440 --> 0:10:39.160 talking to doctor Anna Phillips. She works for the Smithsonian 0:10:39.200 --> 0:10:41.760 Natural histor Museum in Washington, DC, and she is just 0:10:41.800 --> 0:10:44.880 delightful and she's going to tell us all about leeches. 0:10:44.960 --> 0:10:46.679 And wait for it, I'm going to make a connection 0:10:46.800 --> 0:10:49.760 between Kelly's two passions, space and leeches. 0:10:50.120 --> 0:10:54.680 Yeah, that was pretty clever at the end there, All right, enjoy. 0:10:55.400 --> 0:10:59.880 Doctor Anna Phillips is a research zoologist and curator of Klitalata, 0:11:00.000 --> 0:11:02.160 which is a class of anilid worms also known as 0:11:02.200 --> 0:11:06.440 earthworms and parasitic worms. At the Smithsonian Museum of Natural History. 0:11:06.800 --> 0:11:10.760 She studies biodiversity and the evolutionary history of parasitic worms 0:11:10.960 --> 0:11:15.079 and specializes in leeches and tapeworms. She's my hero in 0:11:15.120 --> 0:11:17.760 my world. She's a legend for doing her leech dance 0:11:17.800 --> 0:11:19.719 in a video for the BBC, which we're going to 0:11:19.760 --> 0:11:24.360 discuss later in the show. Welcome Anna, I I'm excited 0:11:24.400 --> 0:11:27.000 to be here. I'm excited to have you here. Did 0:11:27.000 --> 0:11:29.600 I say klitalada rte or did I say it wrong? 0:11:30.600 --> 0:11:31.200 Works for me? 0:11:32.200 --> 0:11:34.440 Nice? Oh man. I always love it when I get 0:11:34.440 --> 0:11:37.560 those slam dugs right from the beginning. So, you know, 0:11:37.960 --> 0:11:40.240 I think for a lot of people when we're growing 0:11:40.320 --> 0:11:42.240 up as kids, like I thought maybe I would study 0:11:42.760 --> 0:11:47.199 tigers or elephants, or you know, maybe anything other than 0:11:47.720 --> 0:11:50.480 worms living in the brains of fish. What was your 0:11:50.640 --> 0:11:52.600 path to getting excited about leeches. 0:11:53.120 --> 0:11:55.160 I was definitely not a five year old who thought 0:11:55.160 --> 0:11:57.480 I would grow up to study worms. It was a 0:11:57.520 --> 0:12:00.839 little bit of a winding road. When I was a kid, 0:12:00.880 --> 0:12:05.040 I was really excited about dinosaurs. They were sort of 0:12:05.080 --> 0:12:08.480 a good introduction into the scientific world for me. But 0:12:08.520 --> 0:12:11.199 as I got older, I realized there were a lot 0:12:11.240 --> 0:12:14.319 more other cool animals out in the world. And when 0:12:14.360 --> 0:12:18.560 I was an undergraduate, I applied for an internship through 0:12:18.800 --> 0:12:22.320 a program run by the National Science Foundation called Research 0:12:22.320 --> 0:12:26.920 Experience for Undergraduates, the RIU program, and it's funded by 0:12:27.120 --> 0:12:31.160 the National Science Foundation, and it's an opportunity for students 0:12:31.280 --> 0:12:34.240 to go work in science labs and working with me, 0:12:34.320 --> 0:12:37.720 a real scientist, and to work on projects and learn 0:12:37.760 --> 0:12:42.800 about the scientific research process. And there were many different projects. 0:12:43.040 --> 0:12:46.839 There were ones on scorpions and bats and bees and catfish, 0:12:46.960 --> 0:12:49.960 and there was one on leeches. And I thought, oh, no, 0:12:50.000 --> 0:12:53.280 one will apply for the one on leeches. I'll have 0:12:53.360 --> 0:12:58.520 better odds. That's amazing. Yeah, so I applied and it 0:12:58.559 --> 0:13:02.240 turns out six people applied. Oh, but I was selected. 0:13:02.440 --> 0:13:05.440 And that summer ended up being everything I thought science 0:13:05.440 --> 0:13:08.640 should be. There was work with specimens, there was field work. 0:13:08.679 --> 0:13:10.760 I went to a conference, got to work in a 0:13:10.800 --> 0:13:13.360 molecular lab, and we ended up being able to publish 0:13:13.360 --> 0:13:16.840 it nice. So then my advisor invited me back for 0:13:16.880 --> 0:13:20.920 a PhD to expand the project from my internship, and 0:13:21.120 --> 0:13:22.640 it was the rest is history. 0:13:23.640 --> 0:13:25.520 Do you think that you were lucky that you happened 0:13:25.520 --> 0:13:28.040 to stumble on a field you were fascinated by, or 0:13:28.040 --> 0:13:29.800 are you just the kind of person who can dig 0:13:29.800 --> 0:13:33.240 into anything and find the mysteries and the juicy questions, 0:13:33.559 --> 0:13:36.000 and that you just happened to end up in this field. 0:13:36.480 --> 0:13:40.000 I think there's a quality of researchers who like to 0:13:40.040 --> 0:13:42.960 dig in and find the juicy questions. So in some 0:13:43.040 --> 0:13:45.559 sense I could have ended up in other places and 0:13:45.920 --> 0:13:50.200 studying other animals, but leeches ended up being a really 0:13:50.200 --> 0:13:53.640 good fit for me. I had always found worms to 0:13:53.640 --> 0:13:59.199 be more interesting than like molluscs or insects or other things. 0:13:59.360 --> 0:14:01.080 It's also a good fit in the sense that, like, 0:14:01.320 --> 0:14:03.160 no matter where you go in the world, people know 0:14:03.200 --> 0:14:06.760 what leeches are. It's like the one worm that everyone 0:14:06.840 --> 0:14:09.120 You can say like all the bloodsucking worms, and you know, 0:14:09.240 --> 0:14:11.000 sort of point to your skin and people are like, oh, 0:14:11.040 --> 0:14:13.280 I know what that is. So even if they don't 0:14:13.280 --> 0:14:16.080 speak English, I think things worked out in a way. 0:14:16.640 --> 0:14:19.520 But yeah, I do kind of get distracted sometimes and 0:14:19.720 --> 0:14:22.240 find other things that I could dive in on and 0:14:22.320 --> 0:14:24.080 have to go no. No, remember parasites. 0:14:24.840 --> 0:14:26.600 So when students contact me and they say, oh, I 0:14:26.600 --> 0:14:29.240 want to go into marine biology, I'm like, Okay, I 0:14:29.280 --> 0:14:32.840 know you're excited about the dolphins, but an easier way 0:14:33.000 --> 0:14:36.800 in is the dolphin parasites Because fewer people are excited 0:14:36.840 --> 0:14:39.320 about those, and then you can become a marine biologist 0:14:39.320 --> 0:14:42.360 through the parasites. And I'm really hoping that they're going 0:14:42.440 --> 0:14:44.240 to get hooked on the parasites. And I have been 0:14:44.280 --> 0:14:46.320 surprised by how many students do get hooked on the 0:14:46.360 --> 0:14:48.520 parasites and then they're like, yeah, yeah, the dolphins are cool, 0:14:48.720 --> 0:14:50.560 but have you looked at the look at this worm. 0:14:50.600 --> 0:14:53.120 And I'm like, yes, we've hooked you exactly. 0:14:53.200 --> 0:14:54.600 Yeah. And this is what I tell a lot of 0:14:54.680 --> 0:14:57.080 students coming through is that it's good to have a 0:14:57.120 --> 0:14:59.480 goal and to be ambitious and to be aiming for something, 0:14:59.480 --> 0:15:03.880 but also flexibility, to have flexible interest, I would say, 0:15:04.040 --> 0:15:05.960 because like I said, I wanted to study dinosaurs and 0:15:05.960 --> 0:15:08.000 now I study worms and they don't even have fossils. 0:15:09.400 --> 0:15:12.640 But you know, it worked out. I'm pretty happy. 0:15:12.760 --> 0:15:15.640 I'm glad you're happy. So let's talk about where leeches 0:15:15.720 --> 0:15:17.520 are on the tree of life, so like what are 0:15:17.560 --> 0:15:21.120 their closest relatives, and then also like how many species 0:15:21.120 --> 0:15:24.320 of leeches do we think that there are? So, like 0:15:24.360 --> 0:15:28.200 you said in your intro, leeches are clidalate anaalids, so 0:15:28.280 --> 0:15:32.000 an analyta, these are the segmented worms with body cavities. 0:15:32.560 --> 0:15:35.560 So there's all the polykeets, which are the marine worms, 0:15:36.000 --> 0:15:38.800 which I don't focus on those because I don't work 0:15:38.800 --> 0:15:42.160 in marine environments very often. And then the other anelids 0:15:42.200 --> 0:15:45.960 are the clydalit anelids. This includes the oliga keats, which 0:15:45.960 --> 0:15:50.040 includes earthworms. It also includes brankie of deeladins, which are 0:15:50.080 --> 0:15:53.920 the crayfish worms, so they are symbiotic worms that live 0:15:53.960 --> 0:15:58.520 with crayfish. They're not parasitic, they're commensal organism. And then 0:15:58.880 --> 0:16:02.440 they're the leeches. With leeches, about half of them are 0:16:02.440 --> 0:16:03.920 blood feeding and the other half aren't. 0:16:04.160 --> 0:16:05.160 What are the other half doing? 0:16:05.360 --> 0:16:10.200 They're eating insect larvae, bacterial mats, just about anything and 0:16:10.200 --> 0:16:12.960 getting their mouths around. But they're not sucking blood, so 0:16:13.000 --> 0:16:13.960 they're not as interesting. 0:16:15.200 --> 0:16:18.520 So what are the big open science questions about leeches? 0:16:18.640 --> 0:16:20.920 I think it's fascinating that Kelly's first question is like, 0:16:21.240 --> 0:16:23.680 how do these relate to other living critters? Where do 0:16:23.680 --> 0:16:25.120 you put them on the tree of life? How do 0:16:25.120 --> 0:16:27.680 we organize them? Is that the motivating question? Is it, 0:16:27.840 --> 0:16:30.240 like all to try to understand how everything got here 0:16:30.280 --> 0:16:33.080 in the evolutionary history of it? Or are there still mysteries, 0:16:33.120 --> 0:16:35.600 but like, how do leeches accomplish this amazing thing they do? 0:16:35.840 --> 0:16:38.520 What are the sort of biggest open questions there in leeches? 0:16:39.400 --> 0:16:43.040 My research is with systematics and evolutions, so looking at 0:16:43.080 --> 0:16:46.280 the number of species, describing new species, how they're related 0:16:46.320 --> 0:16:49.480 to each other. So that's most of what my expertise is, 0:16:49.520 --> 0:16:52.080 and that's also what I find interesting. There are so 0:16:52.200 --> 0:16:57.000 many other aspects of leech biology that have many interesting questions. 0:16:57.320 --> 0:17:00.840 So for leeches, there's probably between eight hundred and a 0:17:00.880 --> 0:17:04.760 thousand species of leeches in the world, which compared to 0:17:04.800 --> 0:17:07.399 a lot of other worm groups, is pretty small. Like 0:17:07.520 --> 0:17:11.439 Nematodes has probably more than sixteen thousand species. So the 0:17:11.560 --> 0:17:14.480 order of tapeworms that I work in has more than 0:17:14.560 --> 0:17:18.440 thirty five hundred species, so eight hundred is pretty small. 0:17:18.440 --> 0:17:20.359 But what's really cool about leeches is to all the 0:17:20.400 --> 0:17:24.280 different evolutionary transitions within that group. In terms of the 0:17:25.119 --> 0:17:28.080 interesting questions it's looking at, like, wow, we have so 0:17:28.119 --> 0:17:31.360 many different feeding strategies. They occur in so many different environments. 0:17:31.400 --> 0:17:35.360 There's marine leeches, there's terrestrial leeches, there's burrowing leeches as 0:17:35.400 --> 0:17:38.040 well as the blood feeders, and so with all of 0:17:38.040 --> 0:17:43.159 these different evolutionary transitions. It's a more tractable group to 0:17:43.800 --> 0:17:45.720 explore those questions because you don't have to go through 0:17:45.720 --> 0:17:48.720 five hundred species. You can look at smaller groups with 0:17:49.320 --> 0:17:53.440 twenty or something, which is easier to approach. And then, 0:17:53.480 --> 0:17:56.600 like I said, they're pretty accessible. You can go to 0:17:56.680 --> 0:17:58.400 a lot of different places in the world and find 0:17:58.480 --> 0:18:01.159 leeches a lot of different habitats, and that can be 0:18:01.200 --> 0:18:03.719 easier than like studying things in the deep sea, for instance, 0:18:03.720 --> 0:18:06.680 where it's very expensive and revolves a lot of equipment 0:18:06.680 --> 0:18:07.240 and planning. 0:18:07.840 --> 0:18:10.679 So when we asked our audience what they think of 0:18:10.720 --> 0:18:13.600 when they think of leeches, a number of them noted 0:18:13.680 --> 0:18:17.240 that in like medieval times, leeches were used to treat 0:18:17.280 --> 0:18:20.800 like every single disease you could imagine, And so I 0:18:20.840 --> 0:18:22.960 was wondering if you could speak at all to the 0:18:23.040 --> 0:18:26.880 current use of leeches in medicine. I know that's not systematics, 0:18:26.920 --> 0:18:27.960 Is it okay to ask you about that? 0:18:28.400 --> 0:18:31.760 Sure? Yeah, yeah. This is actually one of the points 0:18:31.800 --> 0:18:34.560 of why leeches are important to the world because of 0:18:34.560 --> 0:18:38.159 their use in medicine, they've also been used as a 0:18:38.200 --> 0:18:41.320 model organism in a number of other fields, like neurology, 0:18:41.960 --> 0:18:47.199 and some importance in pharmacology and developmental biology studies. But 0:18:47.480 --> 0:18:49.520 when it comes to their use in medicine, yeah, they 0:18:49.520 --> 0:18:53.000 were really popular in the seventeen eighteen hundreds for blood letting. 0:18:53.440 --> 0:18:58.160 Prior to that, people would cut open arteries and veins 0:18:58.200 --> 0:19:00.720 to balance the humors and get some with the blood out. 0:19:01.359 --> 0:19:04.800 But leeches were an improvement on the situation because it's 0:19:04.840 --> 0:19:08.479 easier to get it to stop bleeding versus when you 0:19:08.520 --> 0:19:12.480 slice open artery in vain that it can be a challenge. Also, 0:19:12.560 --> 0:19:14.320 if you want to take more blood, you put more 0:19:14.400 --> 0:19:16.119 leeches on. If you want to take less blood, you 0:19:16.200 --> 0:19:19.359 take them off. It was a more controllable way of 0:19:19.440 --> 0:19:20.040 blood letting. 0:19:20.440 --> 0:19:22.520 Just to be clear, it wasn't helping anything, right, It 0:19:22.560 --> 0:19:25.879 was just like a less damaging way to damage your patient, 0:19:27.040 --> 0:19:29.080 and that was the benefit back then. Is that right? 0:19:29.480 --> 0:19:33.000 They thought it was helping. Okay, but now we know 0:19:33.080 --> 0:19:36.359 that leeches are only beneficial in certain cases. It's not 0:19:36.359 --> 0:19:39.560