[00:00:05.05] all right welcome everybody to uh the uh to our neuros uh seminar series um this is going to be [00:00:11.12] [00:00:11.12] the uh last seminar of the uh year before we all uh break for because the semester is ending a [00:00:16.17] [00:00:16.17] little early so it's my pleasure to uh introduce lauren o'connell uh lauren is a professor [00:00:22.23] [00:00:22.23] of biology at stanford she did her phd at ut austin and her postdoc at harvard before this um [00:00:30.15] [00:00:31.05] lauren has this really great research program that sort of uh that i think is going to be a really [00:00:36.17] [00:00:36.17] fun listen for us today because of its interface with um ecology behavior and evolution um as well [00:00:42.15] [00:00:42.15] as just outstanding neuroscience so um i'm excited to see where that goes lauren has had uh funding [00:00:48.04] [00:00:48.04] from a number of different uh uh sources uh a career award from nsf the nih uh even the defense [00:00:54.13] [00:00:54.13] uh threat reduction agency because she's gonna be talking about poison dart frogs [00:00:58.08] [00:00:58.08] um as and most recently from the the new york stem cell foundation uh where she's a robertson [00:01:03.22] [00:01:03.22] neuroscience investigator so she's had many many awards i i can't even name them all in a short [00:01:09.07] [00:01:09.07] amount of time we'd be here all day uh but it's a it's a pleasure to have lauren here um and a [00:01:14.10] [00:01:14.10] great treat for us to be able to listen to our seminar so lauren go ahead and take it away and [00:01:18.10] [00:01:18.10] we'll have uh questions at the end if anybody has questions along the way they can post them in chat [00:01:22.08] [00:01:23.09] go ahead and learn okay so thank you all for coming i know it's like the end [00:01:29.05] [00:01:29.05] and most people are going on vacation this week so i appreciate those of you who made it um so uh [00:01:37.16] [00:01:37.16] i'm gonna talk a little bit more about ecology and behavior and evolution than you might be used to [00:01:43.01] [00:01:44.10] with with studying the evolution of reproductive behavior in poison frogs the main model system in [00:01:51.12] [00:01:51.12] my lab so my lab is at stanford university um which is in stanford california um but [00:01:59.18] [00:01:59.18] i want to mention that it rests on the unseated land of the moek maloney people [00:02:04.08] [00:02:06.12] so uh i've always been interested in evolutionary uh the evolution of social behavior and when i was [00:02:13.20] [00:02:13.20] a graduate student i studied the evolution of core conserved social behaviors that you see across [00:02:20.23] [00:02:20.23] all vertebrates so for example oh i didn't ask if you can see my mouse i hope you can see my mouse [00:02:27.01] [00:02:27.20] um can you see my mouse yes great um and so uh this includes like aggressive behavior that you [00:02:35.12] [00:02:35.12] see across all animals and then also sexual behavior here and what i did is i focused on [00:02:40.15] [00:02:41.07] identifying core brain regions that promote these behaviors across all vertebrates but as i be i [00:02:50.00] [00:02:50.00] delved more and more into these uh the evolution of behavior i became more and more interested in [00:02:54.17] [00:02:54.17] what i'm calling kind of evolutionary innovations and behavior so how do new behaviors arise [00:03:00.17] [00:03:01.12] and so half my lab studies this in the context of predator prey interactions [00:03:06.04] [00:03:06.04] and how animals come up with new ways to defend themselves against [00:03:10.00] [00:03:11.05] predation and so some examples here are this is a newts that are salamanders that are [00:03:18.02] [00:03:18.02] that are chemically defended um and the bombardier beetle which kind of started it all [00:03:22.15] [00:03:22.15] uh started the field of uh chemical ecology um but what i'm gonna focus on today is more evolutionary [00:03:29.14] [00:03:29.14] innovations and social behavior and in particular particular parental behavior and so in these [00:03:35.01] [00:03:35.01] pictures what i'm showing you is some you know begging behavior in chicks and a giant water bug [00:03:40.23] [00:03:41.12] dad carrying the eggs on his back and what i find really amazing about parental behavior is that [00:03:47.01] [00:03:47.01] it is you know clearly increases the the fitness of the offspring when the parents are there and [00:03:53.18] [00:03:53.18] yet it has evolved independently many many times and so what we're interested in is when you evolve [00:03:59.07] [00:03:59.07] this new social behavior what do you use the same or different mechanisms in the brain to do that [00:04:05.09] [00:04:07.12] and so my lab in particular focuses on the evolution of family units and what i mean by that [00:04:13.16] [00:04:13.16] is that um this there's this conflict whenever you have a family unit because you can either [00:04:21.22] [00:04:21.22] invest lots of resources in the offspring that you have or you can withhold resources from them [00:04:28.08] [00:04:28.08] to to save for future reproductive bouts and so this can lead to conflict between siblings [00:04:35.22] [00:04:36.12] apparent offspring conflict and also conflict between partners and so we're interested in the [00:04:41.14] [00:04:41.14] evolutionary tuning of this conflict and then how when you know what are the situations [00:04:48.00] [00:04:48.00] in which different social strategies evolve to resolve some of these conflicts [00:04:53.22] [00:04:55.16] um and most of these uh conflicts are shaped by resource availability and so you know [00:05:02.13] [00:05:02.13] as many of you who have siblings know that fighting over resources whether it's your [00:05:06.23] [00:05:06.23] parents attention or the newest toy is a thing that that my kids do all the time and so it's [00:05:12.13] [00:05:13.03] it's being able to attain resources that really shapes the evolution of behavior in many species [00:05:18.13] [00:05:19.22] and so what i'm going to focus on today is the neural basis of parental care and so the reason [00:05:24.13] [00:05:24.13] i started working on this system and this question in the first place around around eight years ago [00:05:31.07] [00:05:31.07] or so is that we know quite a lot about how the br the maternal brain is regulated so there's a lot [00:05:39.11] [00:05:39.11] of decades of beautiful work in laboratory rodents that has taught us a lot about how [00:05:44.08] [00:05:45.07] maternal care is facilitated in the brain but when i started this work we actually didn't know a lot [00:05:51.01] [00:05:51.01] about how fatherhood is carried out in the brain and so this is a question that we wanted to tackle [00:05:57.07] [00:05:58.08] but this is a difficult question because in most mammals when males are involved in parental care [00:06:04.21] [00:06:04.21] it's usually a biparental system meaning that the male is also pair bonding to his mate as well as [00:06:13.01] [00:06:13.01] preparing for the care of offspring and i thought it would be really difficult to disentangle those [00:06:17.16] [00:06:17.16] two things in the brain and so what i needed was a system that had a lot of natural variation [00:06:23.03] [00:06:23.18] in parental behavior and who was caring for the offspring and whether or not they were pair bonded [00:06:29.09] [00:06:31.14] and so what i did is i looked throughout the literature there's a lot of great behavioral [00:06:37.05] [00:06:37.05] ecology literature and a lot of ecological modeling about uh the evolution of parental [00:06:44.10] [00:06:44.10] care and so what i'm showing you here is just a rant a sampling so i have the different kinds of [00:06:50.23] [00:06:50.23] reproductive care on the different rows so male uni parental care bi-parental care and female [00:06:56.21] [00:06:56.21] union parental care and they're separated by different taxa so invertebrates i know i [00:07:02.17] [00:07:02.17] just lumped all the invertebrates together um and then all the the different vertebrataxa so you'll [00:07:08.08] [00:07:08.08] notice also that there is no male uniparental mammals so this is because of lactation [00:07:14.12] [00:07:15.07] and female care is obligatory and then this has not been described in reptiles yet and so what [00:07:23.07] [00:07:23.07] that left me was these other taxa down here that i um to be able to study the onset of male parental [00:07:30.13] [00:07:30.13] behavior without pair bonding and so what i ended up deciding to do is i i've decided to focus on [00:07:37.20] [00:07:37.20] this clade of amphibians here because they showed a bunch of different reproductive strategies [00:07:44.12] [00:07:44.12] and yet they had very similar ecologies so they lived in the same place they utilized some other [00:07:51.12] [00:07:51.12] resources and yet you saw this this real explosion of reproductive strategies in these animals [00:07:57.20] [00:08:00.02] all right and so this is the clade that i work with this is um south american and central [00:08:05.20] [00:08:05.20] american poison frogs these are all frogs that we either have in the lab or study in the field [00:08:12.00] [00:08:12.00] and so many of you have probably seen this like at the zoo or at an aquarium or something like that [00:08:17.05] [00:08:17.05] or on planet earth and so but i want to point out a couple things that you might not know and so the [00:08:25.01] [00:08:25.01] first thing is that you probably know them because they're very charismatic and bright and colorful [00:08:29.11] [00:08:30.13] but what you might not know is the the extent of the variation in coloration so these three frogs [00:08:37.07] [00:08:37.07] here are all the same species they're just in different populations and so different populations [00:08:43.05] [00:08:43.05] have different color patterning that's driven by a mix of predator selection and meat choice so [00:08:50.23] [00:08:50.23] they're bright and colorful to advertise that their toxicity so that they are not a tasty [00:08:56.17] [00:08:56.17] snack because they carry these chemical defenses on their skin but the clade of poison frogs was [00:09:03.16] [00:09:03.16] actually named for their most famous members and what i mean by that is that actually most [00:09:08.15] [00:09:08.15] of the frogs in this clade are brown and drab and non-toxic and so what this gives us those it gives [00:09:16.15] [00:09:16.15] us a nice comparison set to be able to compare non-toxic brown frogs to toxic colorful frogs [00:09:23.22] [00:09:25.11] and finally and what i'm going to focus on today is the uh parental behavior in these frogs [00:09:32.04] [00:09:32.04] these frogs are amazing parents and what you're seeing in these pictures [00:09:35.20] [00:09:36.13] is these frogs are carrying these tadpoles on their back which is a behavior we'll talk a [00:09:42.10] [00:09:42.10] lot about and then in some species where moms are involved such as this picture right here [00:09:46.23] [00:09:48.00] they come back and they feed and take care of their offspring for very long periods of time [00:09:54.00] [00:09:55.16] okay and so the questions that we're going to talk about today are what is the neural basis of [00:10:00.23] [00:10:00.23] these parental behaviors and how does variation in ecology drive these behavioral adaptations they're [00:10:08.08] [00:10:08.08] trying to link back the neuroscience and behavior to the ecological resources that they have [00:10:13.11] [00:10:15.18] okay and so now that i've introduced you to the clay generally i want to start off with [00:10:20.08] [00:10:20.08] a phylogeny and this is impo this phylogeny isn't really important to our work because [00:10:26.12] [00:10:26.12] it gives us a lot of power to ask questions and about this system and so this is just a [00:10:33.20] [00:10:33.20] simplified phylogeny there are about 300 frogs in in the dendrobeta day family and so i'm [00:10:38.19] [00:10:38.19] only showing you a few here but i want to point out a couple of things so one is that toxicity [00:10:44.15] [00:10:45.05] or carrying chemical defenses on their skin has evolved at least four times maybe five and it's [00:10:51.14] [00:10:51.14] marked by these gray boxes that are surrounded by red here and when you evolve toxicity you tend [00:10:59.14] [00:10:59.14] to specialize on have a dietary specialization on eating ancests which is marked by these ants here [00:11:06.21] [00:11:07.22] and then if we map behavior onto this phylogeny what you can see is that ancestrally the all of [00:11:15.18] [00:11:15.18] the frogs here have male uni parental care which is marked here by blue so this is an ancestral [00:11:21.22] [00:11:23.09] phenotype and then in some toxic clades they have evolved other parental care systems some more [00:11:29.20] [00:11:29.20] derived phenotypes where you see female uniprental care and then biparental care and monogamy [00:11:35.12] [00:11:37.11] and so many people are surprised that frogs are amazing parents and so i want to describe to you [00:11:45.18] [00:11:45.18] the the links that they go to to care for their offspring real quick and so it starts off with egg [00:11:53.09] [00:11:53.09] care so unlike most of the temperate zone frogs that you're that you're probably used to in the [00:11:59.07] [00:11:59.07] united states um poison frogs lay their eggs in the leaf litter um so out so not in water and they [00:12:08.06] [00:12:08.06] care for their eggs so they hydrate them and then they protect them from predators [00:12:12.15] [00:12:13.05] and so this is usually dad's job but in some species some species females do this excuse me [00:12:19.11] [00:12:20.02] and when the tadpoles hatch they need to make it to water somehow and so the parents have to [00:12:26.13] [00:12:26.13] take them from their leaf litter nest site to water and to do this they get a piggy back ride [00:12:32.15] [00:12:33.18] and either one at a time or many at a time depending on the species and then [00:12:38.21] [00:12:38.21] once they're deposited in pools you see this egg in some species this egg provisioning behavior [00:12:44.06] [00:12:45.09] and so what's important here is that the sex performing the parental care task [00:12:49.18] [00:12:49.18] differs among closely related species and what that allows us to do is it allows us to ask [00:12:55.07] [00:12:55.22] whether or not these circuits that promote parental behavior are sex specific or if there [00:13:02.00] [00:13:02.17] exists a general circuit for parental care in in the brain [00:13:07.05] [00:13:09.12] all right so these are the three species that i'm mostly going to be talking about today [00:13:14.04] [00:13:14.04] they're pretty closely related renitumea oh faga and dendrobates and then they all [00:13:19.16] [00:13:19.16] show these different parental care strategies that i've been telling you about [00:13:22.21] [00:13:24.13] so the stories that i'm going to be telling you today are one is about offspring transport [00:13:29.18] [00:13:30.12] another which is my favorite behavior and i didn't want to leave it out which is egg provisioning [00:13:35.22] [00:13:35.22] behavior and then at the end we're going to link back these diversification of social behaviors to [00:13:43.01] [00:13:44.02] their toxicity and ecology because they might seem very separate and distinct but they're [00:13:49.09] [00:13:49.09] actually quite tightly interweaved and so we'll come to that at the end [00:13:53.14] [00:13:55.03] all right so first for offspring transport i want to describe this behavior to you a little bit more [00:13:59.20] [00:14:00.17] and so as i mentioned that the parents take care of these growing embryos on the leaf litter [00:14:09.20] [00:14:10.17] when they hatch they have to be transported and this is important for survival so because if the [00:14:17.01] [00:14:17.01] parents don't do this then they'll desiccate and die and so this is a really important behavior for [00:14:23.01] [00:14:23.01] the tadpoles so the frogs also have a very complex environment in their you know rain forest home [00:14:31.16] [00:14:31.16] and so they have to find high quality water pools and so if you think about um the the time span in [00:14:40.00] [00:14:40.00] which these tadpoles evolve or live so they it takes about somewhere between two to five [00:14:46.12] [00:14:46.12] months to complete metamorphosis and so you need a really stable pool of water in which to rear your [00:14:52.17] [00:14:52.17] your tadpoles and so they need a really stable pool and they uh and they there's evidence that [00:15:00.19] [00:15:00.19] they remember where these high quality pools are located they have to get there quickly and [00:15:05.16] [00:15:05.16] come back because one of the first things that happens is that when they are gone for too long [00:15:12.17] [00:15:12.17] and competitors move in and uh commit infanticide and so meaning that the first [00:15:18.23] [00:15:18.23] thing a male does when he takes over a new territory is to eat all the eggs [00:15:23.11] [00:15:24.23] so this is a it's a pretty it's a behavior that's required for offspring survival but is risky for [00:15:31.20] [00:15:31.20] um and leaving the other offspring behind i'm sorry if you could hear my dog right now [00:15:37.09] [00:15:38.15] okay and so the three species i'm going to be focusing on are these this male uni parental [00:15:44.06] [00:15:44.06] care species this female uni parental species and then this by parental and monogamous species and [00:15:50.13] [00:15:50.13] could you say that again the what the statement from your previous slide i did i missed it what [00:15:58.08] [00:15:58.08] was it okay they go into these they remember where the pools are and what did you say was important [00:16:03.09] [00:16:04.06] oh so they so they um they remember where the they so they have to remember where high [00:16:09.05] [00:16:09.05] quality pools are located so they need stable water pools and um they remember where these [00:16:16.00] [00:16:16.00] high water these high quality water pools are located which i'll come back to in a moment [00:16:20.13] [00:16:20.13] and the reason why this is a risky behavior is because when um if they're gone for too [00:16:25.20] [00:16:25.20] long competitors will come and eat the rest of their babies so they only tran this species in [00:16:33.09] [00:16:33.09] particular only transports one tadpole at a time and so the rest of the clutch is left behind [00:16:39.20] [00:16:40.10] which is in a dangerous position for them does that make sense it's totally dangerous [00:16:46.06] [00:16:47.18] thank you no problem and yeah feel free to interrupt me um if you have questions [00:16:54.04] [00:16:56.00] okay so what we did is we used this system to ask if there was a general parental care circuit in [00:17:03.16] [00:17:03.16] the brain so across all sexes or if there was something sex specific about what was happening [00:17:09.09] [00:17:10.04] with this tadpole transport behavior and so what we decided to do was look at what [00:17:15.07] [00:17:15.07] brain regions are involved so before i started my lab no one had like sectioned [00:17:19.20] [00:17:19.20] a poison frog brain and so we weren't really sure where to look and so this was our first [00:17:25.01] [00:17:25.01] task like where in the brain might be facilitating this behavior [00:17:28.15] [00:17:29.11] um and then we also wanted to see what what neuronal cell types were involved so not only [00:17:33.20] [00:17:33.20] what brain regions are involved but what cell types might be promoting the behavior as well [00:17:37.09] [00:17:39.22] so we weren't starting from scratch though i mean yes the amphibian brain was kind of a [00:17:44.08] [00:17:44.08] black box for us but one of the things i did when i was a graduate student is really map out where [00:17:51.12] [00:17:52.08] brain regions are that across vertebrates that regulate social behaviors and so this is really [00:17:59.11] [00:17:59.11] well established in mammals so there's this mesolimbic reward system um that encodes valence [00:18:06.17] [00:18:06.17] of stimuli and this social behavior network and brain regions that overlap between these circuits [00:18:11.22] [00:18:11.22] and so these are brain regions that are really well established and regulating different aspects [00:18:16.12] [00:18:16.12] of social behavior and they have these these canonical like markers that are in these brain [00:18:23.09] [00:18:23.09] regions and so what i did as a graduate student is locate where these brain regions were across all [00:18:29.14] [00:18:29.14] vertebrates um and i and i started i i was working on fish at the time and so i almost did this paper [00:18:36.12] [00:18:36.12] out of out of spite because it's my spite paper i suppose um where because someone told me that fish [00:18:42.13] [00:18:42.13] don't have a reward system which is ridiculous um but uh anyway so i'd set up a nice framework [00:18:48.02] [00:18:48.02] for us because we already then had some idea about where to look in the amphibian brain and so what [00:18:53.11] [00:18:53.11] i'm going to show you is some analyses that look at neural activity in these brain regions and [00:18:59.16] [00:18:59.16] amphibians but they are analogous to these same brain regions that we that you find in mammals [00:19:04.21] [00:19:07.03] so the experiment that we set up is that so we have a very large poison frog colony in our [00:19:11.16] [00:19:11.16] lab where we have tanks set up and so these two species the work was done in the lab the frogs [00:19:18.06] [00:19:18.06] are housed in pairs where they have housing in a pool and then we did uh some experiments in the [00:19:26.08] [00:19:26.08] field and so this is o phagocylvatica we do a lot of field work in ecuador where we keep the frogs [00:19:32.23] [00:19:32.23] in these enclosures and so the reason i'm pointing this out is because in the lab we're able to take [00:19:40.12] [00:19:40.12] both mom and dad the frogs and analyze patterns of neural activity whether you know whether or [00:19:46.13] [00:19:46.13] not they're caring for offspring or not in the field because they're in these enclosures we [00:19:52.00] [00:19:52.00] often don't know who dad is and so we only have females for this species in this study [00:19:57.18] [00:19:59.22] and so what we did is we um compare decided to compare frogs that we're not caring for offspring [00:20:05.20] [00:20:05.20] for those that were doing tadpole transport and the assay that we use for this is um this [00:20:11.09] [00:20:11.09] and probably some of you are already familiar with this um from todd stillman's group but [00:20:18.08] [00:20:18.08] we do this immunohistochemistry for phosphorylated ribosomes and the idea [00:20:22.21] [00:20:22.21] is that when neurons become more active they need to make more protein and so the ribosomes [00:20:29.18] [00:20:29.18] become phosphorylated and so this was originally described by zach knight in mammals before he [00:20:36.17] [00:20:36.17] um when he was a rockefeller before he moved to ucsf and so what that actually looks like is [00:20:42.17] [00:20:42.17] this is so we're doing immunohistochemistry we're staining the neurons that have these [00:20:46.17] [00:20:46.17] phosphorylated ribosomes and so we're essentially counting these brown dots across different brain [00:20:51.18] [00:20:51.18] regions and this work was done by a postdoc in my lab ava fisher who now has her own lab [00:20:58.08] [00:20:58.23] just this year at the university of illinois urbana-champaign he's also accepting students [00:21:06.06] [00:21:06.06] if any of you are interested so um what ava did is she quantified these different cell uh the [00:21:14.08] [00:21:14.08] the number of cells that were positive for this marker across all these different brain regions [00:21:18.04] [00:21:18.04] that i told you about in the previous slide that regulate uh social behavior across vertebrates [00:21:23.20] [00:21:25.03] and so i'm going to show you i'm going to summarize the results here in this drawing [00:21:29.11] [00:21:29.11] um so this is for gender babies tank taurus it's a uniparental species and the sex symbol here will [00:21:36.02] [00:21:36.02] tell you which sex is doing the parental the the tadpole transport and so i'm coloring in the brain [00:21:42.04] [00:21:42.04] regions that were more active when the ta when the frog was doing tadpole transport behavior and so [00:21:48.17] [00:21:48.17] you can see there are quite a number of brain regions that become active during this behavior [00:21:53.03] [00:21:53.03] compared to frogs that are not performing parental frogs that are not performing this tadpole [00:21:58.06] [00:21:58.06] transport task and so you know we could have stopped there and claimed that we had found the [00:22:05.09] [00:22:05.09] neural signature of fatherhood in these frogs but what we decided to do was incorporate these other [00:22:12.08] [00:22:12.08] species too and so this is one of those slides that incorporate like five years of your life [00:22:17.03] [00:22:18.00] because there were so many species and treatment groups and so i'm showing and coloring the other [00:22:23.12] [00:22:23.12] ones in the same way and so what you can see i'm going to point out a couple of things that [00:22:27.16] [00:22:27.16] i think are interesting about this about this data so one is that there are some brain regions [00:22:33.22] [00:22:33.22] like the lateral septum that are active only when males are doing tadpole transport but not females [00:22:39.20] [00:22:40.17] there are some that are active only in monogamous [00:22:43.09] [00:22:44.00] uh and by parental frogs like so this bst is the bed nucleus of the stream it's trio terminalis [00:22:49.05] [00:22:49.20] um and so interestingly this brain region is also active in um like micro biparental micro dissolves [00:22:56.17] [00:22:58.00] and so but what we're going to talk about for now is the overlap across all three species [00:23:03.05] [00:23:03.05] and so there were only two brain regions that were similarly active across all these species [00:23:08.04] [00:23:08.04] whenever we were doing tactical transport looking at topical transport behavior and [00:23:12.02] [00:23:12.02] so i'm going to go into more detail with those today and show you the actual data [00:23:15.11] [00:23:16.04] so this is the pre-optic area that this area and the hypothalamus of our of vertebrates and [00:23:23.11] [00:23:23.11] what i'm showing you here is frogs that we're not caring for offspring these are our controls [00:23:28.19] [00:23:29.16] these are the groups that we're doing tadpole transport but remember only one sex does tadpole [00:23:35.03] [00:23:35.03] transport and so i'm going to highlight who is doing the tadpole transport with this orange box [00:23:40.04] [00:23:40.04] so we took the males transport tadpoles and the species but we also took the non-transporting [00:23:46.10] [00:23:46.10] partner from the same tank and so what you can see is that so on the on the y-axis here we have the [00:23:53.14] [00:23:53.14] the number of psx positive cells and we see that transporting males have an increased number of [00:24:00.12] [00:24:00.12] uh of this neural activity marker in this brain region and then if we look across species we see [00:24:05.18] [00:24:05.18] a very similar trend where the the individual that's doing chad will transport has more [00:24:11.12] [00:24:11.12] neural activity in this brain region i'll also point out that in bi parental and monogamous [00:24:18.04] [00:24:18.04] frogs the female partners of these frogs actually mirror [00:24:21.22] [00:24:22.12] the neural activity patterns of their partner even though they're not doing the tadpole transport and [00:24:27.20] [00:24:28.21] we have a couple ideas about why that's happening which i can come back to if anybody's interested [00:24:34.08] [00:24:36.00] this is the hippocampus or the what what in frogs is called the medial pallium you can think of this [00:24:41.14] [00:24:41.14] as like kind of a pre-cortex area and so what we see here is that again when the in the animals [00:24:50.15] [00:24:50.15] that are individuals that are doing catapult transport we see increased neural activity in [00:24:54.12] [00:24:54.12] this brain region and in our biparental frogs we see that their female partners also mirror the [00:24:59.20] [00:25:00.12] the males okay so i want to dive into this idea or link behavior back to these [00:25:08.10] [00:25:08.10] ecological resources real quick um because i told you that this and there's some work about [00:25:14.00] [00:25:14.00] this that's the last slide could you show that last slide once again oh my god so interesting [00:25:21.20] [00:25:23.22] i agree yeah okay okay all right go keep going i mean i got it okay [00:25:30.04] [00:25:31.12] um all right so i wanna pause and link behavior back to their ecology and the you know the [00:25:39.07] [00:25:39.07] challenges they have to make and decisions they have to make and so there's some evidence that [00:25:43.16] [00:25:43.16] spatial memory is important for finding water like good water pools and transporting frogs [00:25:50.00] [00:25:50.00] um and so what we think is that this neural activity in the hippocampus is actually linked to [00:25:55.11] [00:25:55.11] this spatial memory of water finding um and so what we're doing now this is andreas pasukonas [00:26:01.09] [00:26:01.09] as a postdoc in my lab he's developed these frog trackers so or frog pants and so what these are [00:26:08.08] [00:26:08.08] these are our little pants that we put on the frogs and the rain forest and we can track them [00:26:13.09] [00:26:13.09] for up to a month and follow their movements in the rain forest and also their behaviors [00:26:19.05] [00:26:19.05] and so we're starting to study not only how they find their way in the forest but also [00:26:24.06] [00:26:25.14] you know the basic ecological properties of their reproductive systems and having this field based [00:26:32.13] [00:26:32.13] technology has really allowed us to answer some questions that had never been possible before [00:26:37.14] [00:26:37.14] so it's an exciting future area for us okay so uh the essay i was telling you about this ps6 assay [00:26:46.15] [00:26:46.15] um for neural activity it gave us a really good idea across species and across sexes [00:26:51.20] [00:26:52.12] what brain regions might be promoting tadpole transport behavior but it doesn't tell us what [00:26:57.07] [00:26:57.07] cell types are important you know that especially the pre-optic area is a very [00:27:01.20] [00:27:02.12] very heterogeneous brain region it has lots of different cell types and so we [00:27:06.23] [00:27:06.23] were interested in getting some a little bit more specificity in understanding the neural mechanism [00:27:11.12] [00:27:12.17] and so the reason why we like to use this ps6 antibody is because you can immunoprecipitate [00:27:19.11] [00:27:19.11] the ribosomes and also sequence the aren't the mrna attached to those ribosomes and so what [00:27:25.11] [00:27:25.11] this allows us to do instead of just sequencing the whole brain region it allows us to sequence [00:27:30.04] [00:27:31.03] or select for mrna from active neurons that might that are associated with your behavior of interest [00:27:37.12] [00:27:38.21] and so we did this study uh in parental males so males that were transporting tadpoles versus [00:27:45.11] [00:27:45.11] controls and we we did this assay separately in these two different brain regions the hippocampus [00:27:51.05] [00:27:51.05] and the pre-optic area all right so to show you this data uh let me orient you to uh the [00:28:00.19] [00:28:00.19] the graph for a moment um so if things are above zero so this is log fold enrichment because we're [00:28:08.12] [00:28:08.12] measuring the immunoprecipitated rna and comparing it to the input rna and so it's an enrichment um [00:28:16.15] [00:28:18.00] and so where uh transcripts that are above zero are things that are enriched in transporting [00:28:24.21] [00:28:24.21] mills and so you can take this as some sign of active neurons and below zero is something that [00:28:31.01] [00:28:31.01] our transcripts are depleted in transporting males and so these are more silenced uh neurons [00:28:36.00] [00:28:37.14] and so of course these are neurons that are expressing a lot of different genes [00:28:42.08] [00:28:42.08] where i'll be that's where all these gray dots are coming from um and so what we decided to [00:28:46.08] [00:28:46.08] do was select was us look at specifically at transcripts that specify cell type um in [00:28:53.22] [00:28:53.22] in mammals um and so that's what um and then look to see which ones were significantly [00:29:00.02] [00:29:00.02] different across our groups and so that's what these orange dots are um and i'm going to label [00:29:04.19] [00:29:04.19] these orange dots real quick uh just to give you a sense of what some of these things are [00:29:09.20] [00:29:09.20] some of these things are really interesting to us like this neuropeptide y receptor and this pump c [00:29:15.20] [00:29:15.20] for example and so you what this allowed us or what this gave us was this set of enriched or [00:29:22.13] [00:29:24.06] silenced neurons in the hippocampus that we could then follow up with as being linked to [00:29:31.01] [00:29:31.01] hippocampal function and tadpole transport so what i'm showing you now is the next to it is the [00:29:39.11] [00:29:39.11] the pre-optic area and so i'm showing them to you side by side because they're clearly different i [00:29:44.02] [00:29:44.02] mean they're different brain regions and um and a couple of the neuronal cell types that we found [00:29:50.06] [00:29:50.06] were either active or or silenced during tadpole transport but what i want to focus on is the only [00:29:57.18] [00:29:57.18] overlap the only gene overlap between these two brain regions was this neuropeptide called galanin [00:30:03.07] [00:30:04.06] which i want to describe to you for in a slide so at first when i saw this i was like oh galanin meh [00:30:11.20] [00:30:11.20] it's associated with feeding behavior and i didn't think it was particularly interesting at the time [00:30:16.15] [00:30:17.14] but then one of my colleagues and mentors catherine dulac found that it was also associated [00:30:23.16] [00:30:23.16] with paternal care during my time at harvard and what she found was that or what and what [00:30:30.00] [00:30:30.00] her student found is that well when you give male mice we when you present them with pups they will [00:30:37.07] [00:30:37.20] kill they will commit infanticide but not only do they kill the pups they eat them as well [00:30:42.08] [00:30:42.23] if you leave them in there long enough um but what she found is that when you opt to genetically [00:30:47.22] [00:30:47.22] stimulate gallon and neurons you turn these males from infanticidal males into these caring dabs [00:30:53.18] [00:30:53.18] licking and grooming just with this optogenetic activation of gallon and neurons in their proptic [00:30:58.10] [00:30:58.10] area which is really amazing um and you know makes me jealous of working in mice [00:31:03.20] [00:31:05.05] and so what we begin to think of is well we have a similar situation in our frogs [00:31:10.12] [00:31:10.12] where if where they do commit infanticide for example if they take over a new territory and [00:31:17.22] [00:31:17.22] so we thought maybe that this galan neuronal activation switches them [00:31:22.13] [00:31:23.11] to promoting tadpole transport and so what was also exciting to us about this idea is that [00:31:29.20] [00:31:29.20] the gallon and circuits and rodents in male and female rodents are actually quite similar and so [00:31:34.12] [00:31:35.01] to us this was exciting because it pointed us to a neural mechanism that might [00:31:41.14] [00:31:41.14] be similar across sexes rather than having sex-specific mechanisms of parental care [00:31:46.19] [00:31:48.19] so what we did then is we co-localized our phosphoes6 antibody with gallinin [00:31:54.13] [00:31:55.09] and what i'm showing you here is data for the biparental species and what we um so this is the [00:32:01.11] [00:32:01.11] percent of ps6 positive neurons um in or percent of overlap um between ps6 and gallinin and what we [00:32:09.07] [00:32:09.07] found is that when they're doing tadpole transport both the males and the females had increased [00:32:13.20] [00:32:15.01] activation of gallon and neurons in the biparental species we actually did not see this in our [00:32:20.08] [00:32:20.08] uni parental care species which i think is pretty interesting and we're following up on [00:32:26.08] [00:32:26.21] what other cell types might be important in regulating parental care [00:32:32.21] [00:32:34.17] okay so i think this what i want to bring this idea back to is this larger idea that we have [00:32:43.09] [00:32:44.00] that we and several other people have posited is that whenever you evolve a new social behavior um [00:32:52.19] [00:32:52.19] or you know whether you're an individual switching from solitary to parental care [00:32:57.07] [00:32:58.00] you we tend to see these modification of feeding related circuits and energy related [00:33:02.19] [00:33:03.09] related circuits and we see this time and time again as these species switch from solitary to [00:33:09.22] [00:33:09.22] parental you know across vertebrates and even into invertebrates as well [00:33:14.10] [00:33:14.10] and so we think this might be some common theme when you are when you're evolving new aspects of [00:33:21.01] [00:33:21.18] social interactions okay so just to summarize what i've told you so far that we see overlap [00:33:28.15] [00:33:28.15] and neural mechanisms mediating tadpole transport across species so you see these two brain regions [00:33:34.00] [00:33:34.00] that are active but we also see some species specificity at the neuronal level so there were [00:33:38.17] [00:33:38.17] lots of brain regions that i glazed over where they might be linked to sex differences and [00:33:45.11] [00:33:45.11] interactions between partners so there are lots of interesting things to dig into about why like some [00:33:52.00] [00:33:52.00] brain regions are only active in in bi-parental species for example and then i mentioned this [00:33:58.12] [00:33:58.12] idea about modifying feeding circuits when involved when transitioning to parental behavior [00:34:03.03] [00:34:05.11] okay so the second behavior that we're going to talk about is my favorite behavior which [00:34:09.12] [00:34:09.12] is this egg provisioning behavior and it's an amazing behavior so it'll be a good ride [00:34:14.10] [00:34:16.00] all right so this tadpole uh the the egg provisioning behavior we're gonna talk about this [00:34:21.22] [00:34:21.22] thing called tadpole provisioning um and so in males which is what i've been mostly been talking [00:34:26.21] [00:34:26.21] about uh with this blue frog the whole talk is that you know they care for their clutches they [00:34:34.06] [00:34:34.06] transport their tadpoles to pools of water and in males this is where care stops they leave their [00:34:41.20] [00:34:41.20] tadpoles in water where this water pool is their most important choice and then they go back to [00:34:48.06] [00:34:48.06] raising the rest of their offspring females however in species where females care for [00:34:54.06] [00:34:54.06] offspring they go they have this very costly extended provisioning behavior that is amazing [00:35:00.08] [00:35:01.01] so they also do this egg care behavior they also do this tadpole transport behavior they [00:35:07.12] [00:35:07.12] transport their tadpoles individually into different plants or bromeliads so [00:35:13.03] [00:35:13.03] bromeliads that hold water called phytotomata they put their tadpoles in individual plants [00:35:19.07] [00:35:20.02] and then they need to remember where they put their tadpole because they will come back and [00:35:25.11] [00:35:25.11] feed them about every three days for two months and so what they feed them are these trophic [00:35:31.16] [00:35:31.16] unfertilized eggs and it's a it's a very costly behavior because instead of um going to lay [00:35:39.07] [00:35:39.07] more eggs to lay more you know to generate more babies they're go they're coming back and they're [00:35:45.05] [00:35:45.05] uh continuing to feed the tadpoles that they have so it's this extended provisioning period [00:35:49.12] [00:35:51.11] and so you know what we started to think was like why how and why does such a costly behavior evolve [00:35:59.09] [00:36:00.12] and so this is the question we set out to to do and we appre we uh approach this question a little [00:36:06.13] [00:36:06.13] differently and so what i've been talking to you about for most of our time is south american [00:36:12.17] [00:36:12.17] poison frogs and this is where we do most of our field work and where most of our frogs in [00:36:17.01] [00:36:17.01] the lab are from but and so they have evolved these suite of traits these talk the toxins [00:36:23.09] [00:36:23.09] the coloration the parental care um but what you might not be aware of is that there's this whole [00:36:30.12] [00:36:30.12] other clade of animals in africa so this is the island of madagascar here so the in mantellas [00:36:38.17] [00:36:38.17] so the family mentalids they have also evolved this suite of the same suite of traits defensive [00:36:45.11] [00:36:45.11] chemicals warning coloration and parental care and so what we decided to do is utilize this system [00:36:50.13] [00:36:50.13] to be able to ask about convergence in social and reproductive behavior and so this is about as far [00:36:58.17] [00:36:58.17] apart as you can get in amphibian phylogeny and so the amphibian phylogeny has two main branches of [00:37:05.07] [00:37:05.07] frogs hylidae and renidae and so here is where i'm highlighting with these red arrows where our two [00:37:11.07] [00:37:12.00] different families are um and they you know they separated about 150 140 [00:37:18.17] [00:37:18.17] million years ago so it's about as far apart as you can get in frogs [00:37:21.20] [00:37:23.12] and so what we decided to do was go to ecuador and go to madagascar and run the same behavioral [00:37:29.05] [00:37:29.05] trials where we're looking at moms that are doing this egg provisioning behavior to these tadpoles [00:37:36.10] [00:37:37.03] and so this field work was led by alexandria roland a postdoc in my lab and ava fisher also [00:37:44.02] [00:37:44.23] contributed to this project and so what we looked at was was behavior of the moms brain regions and [00:37:53.03] [00:37:53.03] then some specific neuronal cell types and so before i get into the neuro part though [00:38:01.09] [00:38:01.09] i want to describe a little bit more about the behavior and um just to kind of bring home how [00:38:09.01] [00:38:09.16] costly and really just interesting this behavior is so moms provide these unfertilized trophic [00:38:16.08] [00:38:16.08] eggs to their tadpoles and this extended provisioning benefits offspring we know that [00:38:20.10] [00:38:20.10] tadpoles that are reared with eggs from their moms are more likely to make it to froglet hood [00:38:25.12] [00:38:27.03] and then also these tadpoles beg moms for their meals and so this is a lot like begging behavior [00:38:33.14] [00:38:33.14] and checks and what i'm showing you here is a video we took in ecuador of a tadpole doing this [00:38:39.16] [00:38:39.16] dance next to their mom so they dance for their food and they only do this behavior when they're [00:38:47.03] [00:38:47.03] hungry so it's considered an honest indicator of need and the dance is required for mom to feed [00:38:52.10] [00:38:52.10] them and so they have this special mom offspring communication about need that has evolved here [00:38:59.20] [00:39:02.17] okay so there's some evidence that tadpoles that fed by fed by their moms also carry toxins and but [00:39:08.23] [00:39:08.23] more broadly and what i want to link it to is that this allows for the exploitation of novel habitats [00:39:15.05] [00:39:15.05] and the and then let me explain this idea a little bit further because it's an important one which is [00:39:21.05] [00:39:21.05] that i've told you about or emphasize these water pools and how important they are to our frogs [00:39:27.11] [00:39:27.11] you can either utilize these huge pools over here which have you know a lot of water and a lot of [00:39:33.16] [00:39:33.16] resources but also a lot of predators or you can utilize these tiny phytotomatas so these pools [00:39:41.01] [00:39:41.01] of water in plants where there's not a lot of competition or predation but there's also no food [00:39:47.09] [00:39:48.10] and so what we have is we have this evolution of tadpole and frog behavior that reflects [00:39:54.15] [00:39:54.15] the ecological resources that they use in their environment so this species over here for example [00:40:00.08] [00:40:00.08] you'll see he has about 20 tadpoles on his back this species does the school bus method of tadpole [00:40:06.19] [00:40:06.19] transport and they place all their tadpoles in these huge pools um versus these other species [00:40:13.05] [00:40:13.05] over here that just transport one tadpole at a time into these tiny pools and then have evolved [00:40:20.02] [00:40:20.02] these provisioning strategies to be able to feed their offspring while they're growing in these [00:40:25.01] [00:40:25.01] resource-poor locations okay and so oh this is a video of a tadpole eating an egg it took us [00:40:34.12] [00:40:34.12] forever to get this video in madagascar and i'm i'm super proud of it so i wanted to include it [00:40:39.01] [00:40:40.08] yummy okay and so what we did with this experiment is we did something very similar so we're [00:40:46.10] [00:40:46.10] comparing control and moms that are provisioning tadpoles with eggs and we did the same [00:40:52.21] [00:40:54.13] approach where we were using this to these phosphorylated ribosomes as a [00:40:58.15] [00:40:58.15] proxy for neural activity except in the previous study that i told you about we [00:41:03.07] [00:41:03.07] were comparing closely related species where the sex differed in the behavior [00:41:07.11] [00:41:08.04] in this study i'm talking about two very distant species south america and africa that convergently [00:41:16.21] [00:41:16.21] evolved the same behavior of egg feeding their tadpoles and so what we're asking here is [00:41:23.09] [00:41:23.09] when you evolve the same behavior do you use similar or different mechanisms to do that [00:41:28.21] [00:41:30.17] and so um i want to display this the the data the same so i'm coloring brain [00:41:35.14] [00:41:35.14] regions that are more active when moms are doing the egg provisioning behavior [00:41:41.16] [00:41:42.06] there are a lot of interesting differences here but i'm only going to focus on the similarities [00:41:46.15] [00:41:46.15] which are these the over the only two brain regions that overlapped and their [00:41:50.23] [00:41:50.23] activity patterns were the lateral septum and again this pre-optic area here [00:41:55.09] [00:41:57.14] okay so i'm only going to focus on the pre-optic area for sake of time and what i'm showing you [00:42:02.15] [00:42:02.15] here is that moms that are egg feeding tadpoles have increased neural activity you can see this [00:42:09.05] [00:42:09.05] pretty clearly in this micrograph over here so this is a non-nursing mom and a nursing mom [00:42:13.22] [00:42:15.12] we also call it nursing behavior because it's like this this physiological production uh of [00:42:21.12] [00:42:21.12] food so it's like the frog version of lactation almost um and so we were really excited about this [00:42:28.04] [00:42:28.04] result because the pre-optic area is also really important in maternal behavior in rodents and so [00:42:34.19] [00:42:34.19] what we wanted to ask is that if the neuropeptide oxytocin plays an analogous role in frogs [00:42:41.20] [00:42:41.20] as in mammalian lactation so this again this physiological production of food for your infants [00:42:48.10] [00:42:49.22] and so what we did is we took additional series from the sections that of brains that we collected [00:42:55.14] [00:42:55.14] in the field and co-stained them for phosphorous 6 and oxytocin and then counted the overlap [00:43:02.13] [00:43:03.16] and what we found was the exact opposite of in each species and so we had one species [00:43:10.15] [00:43:10.15] where we had this increase in oxytocin neuron activation during tadpole feeding and another one [00:43:17.16] [00:43:17.16] where it wasn't significant but um but i think that might be a power issue due to our numbers but [00:43:24.04] [00:43:24.04] because it looks like almost a suppression um but again that's not significant and so [00:43:30.08] [00:43:30.08] other studies give similarly contradictory results for the role of oxytocin and social behaviors and [00:43:35.09] [00:43:35.09] at first i when we got these results i was i was a little disappointed uh [00:43:40.04] [00:43:40.17] but and it's one of those results that we had to kind of mull over in our heads for a couple [00:43:45.18] [00:43:45.18] of months before we could really interpret uh what we found and let go of our initial hypothesis and [00:43:53.01] [00:43:53.01] but what we you know came on to in the end which i which i actually really like is that you know [00:43:59.22] [00:43:59.22] they convergently involved these egg provisioning behaviors um so you have this analogous behavior [00:44:07.11] [00:44:07.11] and you have these analogous brain regions that are that are probably contributing to [00:44:12.00] [00:44:12.00] this behavior but the cell types that are promoting the behavior are likely different [00:44:16.21] [00:44:16.21] across these two independent origins and so you can have something that looks very similar [00:44:21.20] [00:44:22.19] at the behavioral level but might have different molecular machinery [00:44:26.13] [00:44:27.07] underlying it okay so i just want to summarize what i told you which is that there's evidence [00:44:34.17] [00:44:34.17] for the shared neural mechanisms but their species specificity at the molecular level [00:44:40.13] [00:44:40.13] and so it looks like um there can be you can utilize the same brain regions which makes [00:44:47.01] [00:44:47.01] sense but then the exact normal cell type that promote a behavior might be different [00:44:51.01] [00:44:52.15] and then uh but what i want to come back to is you know why has this costly behavior evolved and this [00:44:59.18] [00:44:59.18] was one of the the first question or one of our original questions when we set out to do this [00:45:04.19] [00:45:05.14] and so i want to bring your attention back to this phylogeny that i showed you in the beginning [00:45:10.12] [00:45:11.05] and point out to you that there's this toxic clade here and it's only the toxic frogs that have [00:45:18.04] [00:45:18.04] evolved these different parental care strategies so female uniparental care and biparental care [00:45:23.03] [00:45:23.03] and so you know is there a connection there and so what i want to bring it [00:45:28.02] [00:45:28.02] back to in my last five minutes is the linking it back to chemical ecology [00:45:33.01] [00:45:34.15] and so poison frogs um so half my lab studies chemical ecology and how and how [00:45:40.13] [00:45:40.13] the frogs uptake these chemicals and and and the chemical diversity that different species have [00:45:46.04] [00:45:46.19] and so frogs are toxic because of these small molecules they're it's very different from what [00:45:53.01] [00:45:53.01] you might think of like a rattlesnake or a cone snail those are peptide based toxins that are [00:45:58.04] [00:45:58.04] encoded in the genome these are small molecule alkaloids what makes them an alkaloid is they [00:46:03.07] [00:46:03.07] have this ring structure with a nitrogen group in the ring that's what makes it an alkaloid [00:46:08.08] [00:46:09.12] and so but what's interesting about poison frog specifically is that they do not make [00:46:14.17] [00:46:14.17] their toxins themselves they sequester it from their environment so from what they eat [00:46:19.22] [00:46:19.22] so they eat ants and mites and they sequester their chemicals from these arthropods [00:46:24.13] [00:46:25.22] what this means for this story is that the ontogeny of toxicity is different it is it [00:46:32.08] [00:46:32.08] can change across the life span so adults have these defensive chemicals because they eat ants [00:46:38.02] [00:46:38.02] and mites tadpoles on the other hand live in this pool of water what they eat is algae detritus [00:46:46.13] [00:46:47.12] larvae usually mosquito larvae and other tadpoles um and so what that means is that the tadpoles are [00:46:55.01] [00:46:55.01] non poisonous for octobers are non-toxic because they don't have access to these ants [00:46:59.20] [00:46:59.20] and mites and so but there was some evidence from jenny steinovsky that in species where [00:47:05.12] [00:47:05.12] females do egg provisioning the tadpoles that the tadpoles also had toxins and so what we wanted to [00:47:12.02] [00:47:12.02] do is link these things together a little bit more clearly and so while we were in the field [00:47:17.18] [00:47:17.18] we wanted we also collected samples to ask do moms transfer alkaloids to their tadpoles [00:47:25.07] [00:47:25.07] through this egg provisioning strategy they could either do this through the eggs [00:47:29.07] [00:47:30.06] possibly through the water it's hard to disentangle these this experiment doesn't do that [00:47:34.19] [00:47:36.06] and so what we decided to take as samples in the field were uh skin samples from moms from tadpoles [00:47:43.18] [00:47:43.18] um internal eggs from moms this would allow us to determine if moms loaded toxins into [00:47:50.08] [00:47:50.08] the eggs prior to them them being laid these trophic eggs that were laid for the tadpoles [00:47:56.08] [00:47:56.08] and also the tadpole water and this was done by a graduate student in my lab nora moskowitz [00:48:02.21] [00:48:05.03] and so what i'm showing you here is just one species our ecuadorian species and so what i'm [00:48:09.22] [00:48:09.22] going to do this in a bubble chart and this bubble 100 is the toxins that moms have on their skin and [00:48:19.12] [00:48:19.12] so when we look in the oocytes we see about seven it we the oocytes have about 70 of the toxins that [00:48:26.08] [00:48:26.08] we see on mom's skin and so it does look like they are loading their eggs with alkaloids when we look [00:48:34.13] [00:48:34.13] at the tadpoles we see that they have about 50 percent of the toxin profiles of their mothers [00:48:39.20] [00:48:40.17] and then when we look at both the eggs and the water we also see alkaloids um in in in [00:48:46.19] [00:48:46.19] those samples as well and so it looks like from this that that the mothers are uh provisioning [00:48:55.01] [00:48:55.01] their tadpoles not only with nutritive eggs but also with chemical defenses that [00:49:00.10] [00:49:00.10] allow the tadpoles to protect themselves from predation we also think that this [00:49:05.20] [00:49:06.10] toxic water is also interesting these water pools are coveted resources and so we think [00:49:13.03] [00:49:13.03] that this might be a way also to protect their environment and so but if the ability to transfer [00:49:21.07] [00:49:21.07] toxins to your offspring was really important for the evolution of provisioning behavior we should [00:49:27.09] [00:49:27.09] see this not only in the south american species but we should also see it in our malagasy species [00:49:34.12] [00:49:35.22] and so then what we did is so we did the same experiment from our malagasy frogs and we find [00:49:43.20] [00:49:44.15] the same things meaning that moms load their eggs with toxins they feed these [00:49:53.11] [00:49:53.11] toxin-laced eggs to their tadpoles who start to accumulate them um as for for defense as well [00:50:00.12] [00:50:02.13] okay so the takeaway here is that this egg provisioning provides both nutritive [00:50:07.16] [00:50:08.08] uh benefits as well as chemical defense benefits and so these are likely both [00:50:14.04] [00:50:14.04] additive adaptive advantages to this very costly feeding behavior that these frogs have evolved [00:50:20.13] [00:50:22.17] okay so i just want to sum up now across all the studies and where i talked about there were [00:50:31.01] [00:50:31.01] shared mechanisms involved in tadpole transport among poison frogs and across vertebrates and [00:50:36.13] [00:50:36.13] what i you know the example that i gave you was this gown in an example where it might promote [00:50:41.05] [00:50:41.05] tadpole transport behavior similar to what it does in rodents and we saw this was the [00:50:46.19] [00:50:46.19] case in one species and what i think is really amazing about this is that you know they care [00:50:55.03] [00:50:55.03] has evolved independently clearly in frogs and in mammals and we're seeing the same cell types [00:51:02.00] [00:51:02.00] and same circuitry being recruited to promote that behavior and i think that's that's really [00:51:07.01] [00:51:07.01] amazing so there was one example of like similar recruitment and independent evolution of behavior [00:51:12.17] [00:51:14.13] and then i talked about this egg provisioning example where we see actually species-specific [00:51:20.10] [00:51:20.10] mechanisms so they have this similar behavior but the uh an independent origin of [00:51:27.01] [00:51:27.01] egg provisioning behavior but the we're finding that the neuronal differences across these species [00:51:33.16] [00:51:33.16] are are quite pronounced and so we we found that you know sometimes the same circuitry is [00:51:40.17] [00:51:40.17] recruited and sometimes not and so what allowed us to do this though is this comparative approach of [00:51:48.04] [00:51:48.04] comparing many different species at both shallow and wide evolutionary distances and this is the [00:51:55.16] [00:51:55.16] only way we were able to figure this out whether or not circuits are evolutionary flexible or not [00:52:04.13] [00:52:06.21] okay and then finally um i just want to say that a lot of the innovative aspects of our [00:52:12.13] [00:52:12.13] the behaviors that we see are tightly linked to their ecology which is why we continue to do both [00:52:18.06] [00:52:18.06] field work and laboratory studies which are really important for integrating artwork together and so [00:52:25.07] [00:52:25.07] i want to thank really quick my lab i finally took a zoom picture and gave up on the idea [00:52:31.05] [00:52:31.05] we'd all be together um very soon uh and so but i also really want to thank our local collaborators [00:52:38.08] [00:52:38.08] in ecuador and madagascar we um collaborate with local scientists um in an effort to you know uh [00:52:46.17] [00:52:47.12] to decolonize field-based science and so they their partnerships with them are really are [00:52:53.18] [00:52:53.18] really valuable to us and i'm very grateful that they that they collaborate with our group [00:52:58.13] [00:52:59.11] all right and i'll take any questions and thank you all for listening [00:53:03.01] [00:53:09.07] hello hi lauren thanks for such an amazing guy can you hear me yes i can hear you all right [00:53:16.10] [00:53:16.10] uh so in one of your slides you talked about uh the tadpoles performing at dance uh for their [00:53:22.15] [00:53:22.15] mom to feed them i'm quite new to this research i was wondering if the dance is accompanied by [00:53:29.01] [00:53:29.01] vocalization because we know in most uh species uh babies or pops will vocalize for the appearance [00:53:36.06] [00:53:36.06] like feed them isn't known if the typos have any form of like vocalization that goes from [00:53:41.20] [00:53:41.20] the dance and which is more dependent on deciding uh what the mom would use in feeding the that ball [00:53:49.05] [00:53:49.05] yeah yeah so um my lab actually a lot of people in my lab work on this tadpole communication [00:53:55.22] [00:53:55.22] behavior now um i just didn't have like a complete story to present um in a talk but [00:54:01.18] [00:54:01.18] i can summarize to you what we've found and also answer your question about vocalizations [00:54:06.15] [00:54:07.07] and so right like in in rodents they make these vocalizations um and some really interesting work [00:54:15.01] [00:54:15.01] oh his name is falling out of my brain right now but um he's at yale and what he's found is that [00:54:20.08] [00:54:20.08] they do these vocalizations and it's linked to agrp neurons but actually it's not linked [00:54:26.00] [00:54:26.00] to nutritional need but more like nest separation anxiety and some really beautiful studies [00:54:31.16] [00:54:32.06] um that his lab did and so um in our tadpoles the malagasy tadpoles vocalize they do not dance in so [00:54:42.23] [00:54:42.23] the south american tadpoles they do not vocalize but they do dance and so we're trying to figure [00:54:49.16] [00:54:49.16] out um what the components are of the the emotion that is important for moms to feed them and so [00:54:59.01] [00:54:59.01] what we've done is we um and this is the work by my graduate student my lab billy goolsby [00:55:05.03] [00:55:05.03] and so what she's done is she's created a robotic tadpole where we she can manipulate the frequency [00:55:11.12] [00:55:11.12] of movement and the size of the tadpole to look at both you know how much do parents invest [00:55:17.05] [00:55:17.18] in in offspring quality versus the actual signal and so were you she's using that robotic tadpole [00:55:24.15] [00:55:24.15] to really dissect apart the signals that might be important to communicate need [00:55:28.17] [00:55:29.07] uh to moms thank you so much yeah yes yeah that answered this question thank you [00:55:35.12] [00:55:37.16] so i have a couple questions i'm really interested in convergent behavior [00:55:41.22] [00:55:42.13] and so i was trying to figure out okay parental care [00:55:45.11] [00:55:46.10] you have moms versus dads taking care of the tadpoles in all the ways that you describe uh and [00:55:52.19] [00:55:53.14] i was wondering do you see the alternative strategy of having a large yoke ever [00:56:00.21] [00:56:02.17] oh like what is the yolk investment across species yeah yeah because um most of us [00:56:08.17] [00:56:10.17] like humans use the mom so these frogs do something really cool yeah um i don't think [00:56:20.23] [00:56:20.23] anybody's in particular measured yolk what i can say is about egg size as a proxy yeah yeah [00:56:29.09] [00:56:29.09] that's a proxy and that uh that the species who do male uni parental care tend to have [00:56:37.07] [00:56:37.07] much larger eggs for larger eggs so these eggs are way bigger than xenopus eggs i mean they're huge [00:56:43.20] [00:56:45.05] you know some of them can be like the size of a green pea they're very easy to inject um and so [00:56:51.07] [00:56:51.07] it's because they don't make as many right so like xenopus make like 10 000 tiny eggs [00:56:56.08] [00:56:56.08] and these frogs make like you know somewhere between 10 and 50. yeah yeah so that's the [00:57:02.13] [00:57:03.07] trade-off yeah yeah so there's a trade-off there in yoke deposition yeah so i was just [00:57:09.11] [00:57:09.11] trying to think you know because the brain sections the hippocampus is huge and spatially [00:57:18.10] [00:57:19.01] you know remembering species so that the uh frog that makes the oh large yolk no you're saying your [00:57:29.16] [00:57:29.16] babies make large babe yolk wait a minute i was trying to figure out whether they would change [00:57:35.09] [00:57:35.09] like the the plate in general has very large eggs and then we see that actually like just i've never [00:57:41.18] [00:57:41.18] measured this so this is just like my what it looks like to me which is that species that [00:57:48.12] [00:57:49.05] have male universal care have larger eggs um and and these are species that don't have this [00:57:56.00] [00:57:56.00] egg provisioning behavior so if you if you want to look at it in that way like [00:58:00.19] [00:58:00.19] species that have egg provisioning have don't have as much yolk to go on which is perhaps okay [00:58:05.22] [00:58:05.22] because their moms come back and feed them anyways yeah no that's okay so that's just the alternative [00:58:11.18] [00:58:11.18] strategy by other animals and then my last question had to do with predator defenses so that [00:58:18.02] [00:58:19.01] uh you're saying that they will do this provisioning behavior in [00:58:25.09] [00:58:26.06] uh small ponds bromeliad ponds that don't have predators is that right yeah predation is lower [00:58:34.13] [00:58:34.13] so the the main thing that eats tadpoles are dragonfly nymphs or other tadpoles and so [00:58:41.16] [00:58:42.08] um and you don't have either of those in these small pools oh yeah because the defenses you know [00:58:48.13] [00:58:48.13] i was just thinking about the cost you have coloration first of all to say oh i'm toxic [00:58:53.20] [00:58:54.23] and then you have you know yeah that's the first one yeah the frogs actually get their color during [00:59:02.17] [00:59:02.17] metamorphosis so like when they're preparing to leave the water before that they're actually brown [00:59:08.23] [00:59:08.23] um so cool yeah so they're fully colored up by the time they walk on to land oh my gosh so so [00:59:17.20] [00:59:18.13] what are you interested in thank you bye all right yeah i just i greg george had a question [00:59:23.14] [00:59:23.14] in there okay yeah thank you guys i want to give chance for everyone so we have a time for maybe [00:59:28.02] [00:59:28.02] one more question george do you want to ask your question or do you want me to ask it from chat [00:59:31.20] [00:59:33.03] yeah i can ask the question hi um that was a great talk i was just uh wondering about your no [00:59:40.10] [00:59:40.10] transport condition in the mail transport behavior of the tadpoles i was wondering like was it just [00:59:47.07] [00:59:47.07] like a frog without any eggs or was it like a frog with eggs that you removed the eggs or how [00:59:52.23] [00:59:52.23] did that work yeah so in our original experiment we'd had we had three groups and we actually just [01:00:00.02] [01:00:00.02] ended up publishing two of them and one was um a group that was doing egg care um and then another [01:00:07.14] [01:00:07.14] and we published that separately and then another the no care group so what those animals were is [01:00:13.07] [01:00:13.07] that they were sexually experienced so they had to to meet the criteria they had to have successfully [01:00:19.18] [01:00:19.18] raised and transported and to clutches of tadpoles to be included in the study because [01:00:27.05] [01:00:27.05] we were worried about how experience might influence brain architecture [01:00:32.00] [01:00:32.23] and so they were experienced parents but who were not currently caring for a clutch at the time [01:00:38.08] [01:00:41.09] did they answer your question okay yeah thanks so i think we need to wrap up that we [01:00:47.05] [01:00:47.05] are a little over time so thank you so much again lauren uh everybody's applauding but [01:00:51.05] [01:00:51.05] and some people have already had to go so but it's always so hard to hear over blue jeans [01:00:54.19] [01:00:54.19] or assume that but that was a fantastic talk i really enjoyed it and um thanks everybody [01:00:59.07] [01:00:59.07] for uh coming to our seminar this time and uh throughout the semester we'll reconvene in the [01:01:03.22] [01:01:09.01] even if your spring [01:01:09.20]