 I'm Rebecca, and I and my co-boss, Rick, would like to welcome you to Nerd Night East Bay. Thank you for coming out here this Thanksgiving week. We've got some really great talks for you. We've got kind of a sexy, sex theme going on. It's pretty safe for work, but it's still kind of sexy. A few things before we jump into the talks. We've got the Oakland Public Library here. Yes, check out the waiting notes back. So if you haven't yet, during the break, please go over, say hi. We have book lists, resource lists that tie into the talks provided by our wonderful speakers. We have the opportunity to sign up for a library card if you don't have one yet, which is sad and shameful and should be corrected immediately. We also have the Berkeley Science Review here. So if you want to get a copy of that, it's available at the same table. So let's talk about our first talk. It's going to be about the spiders. Now, we're all nerds here. We're scientists. We love spiders and all animals. Of course, they're rad, but they're also kind of scary, okay? We can admit it, some of us find them to be so. If you don't think that they are, I just wanted to present a few examples. Yeah, the Goliath bird eater. Yeah, this is the world's largest spider by like total mass. They're very large and come on, it's terrifying. I'm sure they're very friendly. And this one is the largest spider by length, man. Yeah, yeah, the giant huntsman. So I had to put this away like pictures so you could get a good perspective. We are scientists. We don't kill it with fire. We study it, but it did make me wonder why are spiders particularly so creepy sometimes? And so I did a little minor research on it to try to figure out if there's any understanding of why spiders particularly creep me out anyway. And there have been people looking into it, but there's no definitive answers. What I found is that in one study that found it's probably conditioning, meaning people had bad experiences, people who have arachnophobia specifically had bad experiences with spiders at some point, got bit or something like that, and it sticks with them. This study, however, also found that when children were given an open-ended question, what's the thing you're most scared of? Spiders was the number one answer. I think it's kind of interesting. But other studies have sort of indicated that maybe it's not about conditioning and more just genetic, that people have it running in their families, arachnophobia specifically. Yeah, and some people hypothesize that the specific characteristics of the spider just really activate something that we're hardwired to be terrified of because of their angular legs and scuttling motion and unpredictable movements. And there's also this hypothesis about the nature deficit disorder. Oh, is that making noise? That's all right, let's turn it off. Okay, sorry, that kids don't spend enough time outside enjoying nature, interacting with nature, and therefore become uneasy with things from nature, specifically insects, but I guess I also could apply to spiders because they're also creepy and crawly. But again, we're scientists. We are going to dispassionately study, no, we're going to passionately study spiders, but we're going to have a positive, enjoyable experience because these are cute spiders that dance and do awesome things and have sex. So I know you're dying to learn about the sexy dancing spiders, so I will not delay any further. Here's Erin Brant to tell us all about them. Thank you very much. And I suppose I should take a minute or two just to address what was said about the scary spiders. So the giant puppy dog sized spider, those are total pussycats. Those are like some of the favorite spiders of tarantula keepers because they're so friendly. And the huntsman spiders similarly. They tend to freak people out a lot. They live in Australia, but they are absolutely totally harmless, much like all the spiders we have around here. So there's no brown recluses here. We have black widows, but they haven't killed anyone in 40 years. And in general, spiders around, especially in this area are totally friendly. So without further ado, I will begin my talk where we will be talking about sexy spiders. So here is an example of one such sexy spider. It's a male and he's got adorable little eyebrows and we'll be getting to him in a moment. So today we're talking about sex. Yay! Sexual selection menace. So when we study sex in a biological context, we put it in an evolutionary context. So sexual selection is half of the evolutionary forces that drive animals to evolve in certain ways. So if you think about natural selection as survival of the fittest, so on sex, intersexual selection. So intersexual selection favors traits that cause one sex to battle with each other for access to the other sex. So we have examples like these chickens battling for the lady chickens. These elephant seals battling very bloodily for the lady elephant seals. So we also have between sex selection. We have intersexual selection. And this is where you have elaboration of traits, frequently called sexual ornaments. It's not a Christmas tree thing. It's just some characteristic that is attracted to the other sex. So you frequently think of things like birds. Look at that male bird, how goofy he looks and he is going to attract the lady birds. Or look at that monkey who is evidently attracting the lady monkeys as well. So this latter part of selection, this between intersexual selection is my particular subject of interest and what people in my lab study. So why are females choosy? Why do males do these ridiculous things? What is it about the females that they're choosing these things? So there's a few different hypotheses and they're really difficult to tell apart. So for instance, the male might provide something into the female. So the male might say, hey, if you mate with me, I'll provide you a snack. Or the male has good genes. Hey, if you mate with me, babe is really awesome and they'll have lots of sex and have lots of babies. Or sometimes the females like males just because. So in some cases, literally the cases happen where in certain fishes, the females like the color orange. And if the males are orange, the females will like them and it's not really connected to anything. That's just the case. And finally, the male could be manipulating the male. The male could be manipulating the female, rather, such that the male knows that the female likes a certain thing so he manipulates her to mating with him even though he's not a very good male. So this is kind of a complex body of research and it's difficult to tell these hypotheses apart. So how are we going to investigate this? Well, we're going to use a model system. And when you think of model systems with sexual selection, you're gonna think of birds, maybe fish, maybe birds or some more birds. But I'm going to make the argument that jumping spiders make a fantastic model system, in particular this genus hibernatus. So these are all examples of jumping spiders in the genus hibernatus. These are all males and this is about a quarter of the number of species that are found in this genus. They're found all in North America and into Mexico. And the males are very brightly colored, they do songs, they do dances, we'll get to see lots of that, it'll be really exciting. The females look incredibly unremarkable. So when you see them on the ground, when you're looking for them, they're indistinguishable from closet dirt. And I actually have some live animals next door, if you guys wanna have a look at some point, you can see the difference between a male and a female. Okay, so what's interesting about these, why are they good model systems? Well, first of all, the males have these dynamic visual ornaments and they do these songs. So they're visual and then they do these songs. So these are just three sounds as examples of one species of jumping spider in the genus, hibernatus. Multiply by that by 150 and you'll get an idea of the diversity of the songs that these guys sang. And we'll get to show you a little bit of that. So here's an example song. These are the different sounding. Like the males? Or we don't like the males. So we are going to use the natural selective force of the applause meter to determine. So, male one quality of dance, applause. Coordination of dance and song. Male number one. Coordination number two, vigorousness of dance. Number one, vigorousness number two. Hibernatus plain Jane has won this. So hopefully we've had a practical demonstration that has brought home a few of the basic principles of doing science. So, in summary here, first of all I think the most important thing to recognize with us is that females are incredibly powerful in these systems because the males are not going to evolve anything unless the females want it to happen. Second of all, complexity is everywhere in nature, everywhere not just birds or birds or more birds but you can find really interesting and fascinating model systems in lots of different places just like studying sexual selection in jumping spiders for instance. Finally, sex is diverse and fascinating as you look across the animal kingdom. So I will close with a picture of, okay, questions. Yes. How did they first discover that these spiders being sound if they can't potively hear them? So this was actually something that my advisor discovered and it was known that these jumping spiders do these crazy dances. So my advisor actually said, I wonder if they do vibrations? So the very first setup that they had was basically a record needle that they had that could detect the vibrations and very analog transfer them to recording media. And we have much more advanced techniques now but it was very much just, I wonder if they do this and why would they ever? Yes. What was the outcome in the videos we saw that those males mean success? That's a good question. I would say that, oh, did the males have success in the videos? I'm not entirely sure. Most of those were my advisor's videos from his grad work and I would guess that probably about half of them had females that were not in a position to be accepted or rejecting. However, usually, at least in the species I study, there's about a 30% mating rate. So chances are pretty good that the female found him acceptable. Also, sometimes if the females don't like the male, she'll cut the whole thing pretty short. She'll kind of lunge at them or eat them. So didn't the males, did the males? No, so there's kind of a time limited dance that they do. So some species is one to five minutes, others will go for two hours. But at the end, they'll mount the female and you have to get the paint brush out. No, no, that's not a real female. It's not for her. They can't figure it out. Yeah, Natalie. Are there any capital gains breeding programs or do you always have to cut them in the wild? Well, I have a kids breeding program going on that consists of a box of spiders in my lab right now. They're very, very difficult to rear. So my lab mate reared some and she had about a 75% mortality rate. You pretty much have to collect these one by one in the desert. The babies are just very delicate and they're incredibly difficult to rear. Yeah. Have you found yourself generalizing to... Have I found myself generalizing these principles to humans perhaps, in general or specifically? So studying animal behavior, it's really, really difficult not to anthropomorphize absolutely everything. And I think we kind of tend to have a bit of a barrier there. I personally don't ever, ever, ever want to study humans because they're so complex and you have to file paperwork and all these sorts of things. So I tend to not think of those things in those terms. It's kind of challenging not to when you see certain examples of behaviors like different courtship and like, oh, that's a courtship behavior, ha ha ha. But in general, no, because animals are so diverse but so specific to their species. It's difficult to draw generalizations. Yeah, that's it. What is the capture process like for jumping spiders? It involves a vial. It usually involves someone very dirty and covered in bruises from falling off cliffs and you do this. And when you see one, you drop to the ground and gently nudge him into the vial. So if you capture it 25 in a day, you're doing pretty good. So it's, so when you're looking at female preferences, so you're trying to figure out what females are interested in, you need sample sizes in the hundreds. So, and they all have to be immature females because once they're mature, you can't know if they've made it and they only made one time. So if you shoot to get three or 400 immature females, that could be probably three to four weeks in the field at least every day. So it's a challenging system to work with for that reason. Okay, one. So are females the only choosy sex? That's actually a really interesting question and that's a big area of research right now. There's the idea that there's choosiness on both sides and I think it would be ridiculous to say that that just doesn't happen at all because at the very least the male needs to make sure it's the right species, otherwise he's just wasting his time. So because we know so little about the choices that the females make, we haven't really been able to look at the other side of that yet. But I think that would definitely be an awesome direction to go into after we have the female end of things work out a little bit. Yeah, I can't really see you guys. Yes, with your ornaments. You mentioned the novel male earlier. So like gummies will go for the least common color of gummies in the pond. You mentioned the petapult moment. Are there like remixes to like different songs sometimes? So as far as we can tell the dances are pretty genetically determined. We don't see a lot of variation and usually if there's variation that means the females aren't gonna like the male. That said, you do see hybrids of these guys in the field occasionally. We see them rare enough that it's difficult to find them and look at their dances and figure out what's going on with that. But definitely just, you know, those two different mountain ranges change their dance with, and they haven't been separated for that long like tens of thousands of years, which is a blink of an eye in evolutionary timescale. So these things are definitely changeable and we think that it's primarily genetic. One more? Yes. So the only plasticity or do the males change their dances at all is the question. The only plasticity that we've seen is sometimes, so some of these males have like an hour or two hour long displays and every once in a while you get one that kind of jumps the gun and he'll skip steps and he never has success with that. The females do not go for that at all. So other than that, everything seems pretty stereotyped within a species. But that's definitely something to look at. Again, because we have such small sample sizes because these guys are so hard to find, it's difficult to get a good sense of what the variation is like within the species. I think that's nice. One more one earlier, I was very excited to tell everyone that during the break you got to sign up for a library card. We're gonna have a 15 minute break and when we come back, we will have brain science stuff.