0:12 this is from our neurons to yours a
0:15 podcast from the WOAI neurosciences
0:17 Institute at Stanford University on this
0:19 show we crisscross scientific
0:21 disciplines to bring you to the
0:24 frontiers of brain science I'm your host Nicholas
0:31 Wier [Music]
0:38 here's the sound we created to introduce today's
0:47 [Music] [Applause]
0:50 [Applause] [Music]
0:59 episode perhaps that is the sound of
1:01 frog parent parenting today we're going
1:04 to talk about frogs and spiders as
1:07 parents bear with me for a minute what
1:09 today's show is really about is the idea
1:11 of pair bonding that's the scientific
1:13 term for the collaborative bonds that
1:15 form between two parents as well as the
1:17 bonds between parents and their
1:20 offspring we're obviously familiar with
1:22 the example of family Bonds in our own
1:24 species and you probably have ideas
1:27 about what families look like in animals
1:30 like wolves let's say or swans that made
1:32 for life but it turns out that if you
1:34 look across the animal kingdom strong
1:37 family bonds are way more widespread
1:39 than you might imagine frogs have them
1:41 spiders have them fish have them we
1:43 wanted to learn more about the
1:45 Neuroscience Behind These family bonds
1:48 across the animal kingdom and what this
1:50 could teach us about our own experience
1:53 as partners and as parents plus I just
1:55 wanted to talk about frogs this week
1:57 Stanford biologist Lauren oconnell and
1:59 her lab travel around the world studying
2:02 boys and frogs wolf spiders butterfly
2:04 fish and other animals that it turns out
2:06 are pretty amazing
2:08 parents I started the conversation by
2:10 asking Lauren to tell me why she studies
2:13 parab bonding in frogs her lab
2:15 specialty the main reason we study
2:17 amphibians is because they have a huge
2:21 diversity in behaviors so there are some
2:23 species that where only dads care for
2:25 Offspring there are some species where
2:27 only mons do this and there are some
2:28 species where they do teamwork to raise
2:30 their offspring there's some species
2:32 that you know they're like hey I'm I'm
2:34 going to lay these eggs then I'm out and
2:38 so what we can do then is we can use
2:40 this behavioral diversity to really dig
2:44 into the neuroscience and understand how
2:46 different neural circuits give rise to
2:49 different behaviors so you rais a good
2:50 point which is that you know this is a
2:53 neuroscience show and parenting Behavior
2:55 feels sort of like you that's something
2:57 that we learn about in biology classes
2:59 and ecology and so on so so what is the
3:01 big Neuroscience question that motivates
3:05 you when I was in graduate school I was
3:08 working on my own parental Care Project
3:10 I was you know pregnant and about to
3:13 have my first kid right
3:16 I and so I was very interested in
3:19 Parental care literature and I found
3:21 that we understand quite a lot about
3:24 maternal care from laboratory rodents
3:26 but we know very little about what
3:29 happens in the brains of fathers mostly
3:31 because laboratory rodents very rarely
3:34 display paternal care and so what I
3:36 wanted to do was I wanted to study what
3:39 are the sex differences or similarities
3:42 in how the brain produces a parental
3:45 care behavior and so to be able to do
3:48 that I wanted to really
3:51 disentangle paternal care and maternal
3:54 care and separate this from Pair bonding
3:56 because usually in mammals when you have
3:58 males caring for Offspring they also are
4:01 peir bonded to the mate and those two
4:03 neural pathways are really difficult to
4:06 disentangle that's really interesting so
4:08 maybe we can take a step back I mean
4:12 when did joint parent care evolve in the
4:14 history of life it's evolved
4:17 independently many times invertebrates
4:20 and invertebrates in each lineage
4:22 especially in invertebrates there has
4:24 been independent transitions to parental
4:26 care and what drives the evolution of
4:28 pair bonding and parental care can be
4:31 very different across Texa so in mammals
4:33 you know we have the definition of being
4:35 a mammal you know is like lactation
4:38 where moms are caring for Offspring when
4:39 you're live living in an environment
4:42 where resources are really few and far
4:44 between you get care bonding and
4:46 paternal care where it's actually
4:48 adventage just for the male to actually
4:52 stick around but in other animals where
4:55 you know lactation is not a requisite or
4:57 an ancestral feature there can be lots
5:01 of different ways and and reasons to
5:04 evolve pair bonding so I think that I've
5:06 always assumed that pair bonding is
5:09 there basically to keep the data around
5:11 but it sounds like that is a Maman
5:14 perspective to take yes yeah I think
5:17 that's very much a mammals perspective
5:20 so in other taxa there are other reasons
5:23 for couples to stick together for
5:25 example in butterfly fish the reason
5:28 that they form pair bonds is actually
5:31 resource defense or territorial defense
5:34 so they defend corals that are their
5:36 food resources and they actually just
5:38 spawn into the water column and so
5:41 there's no parental care at all but they
5:43 have these pair bonds most of them are
5:45 male female pair bonds but we also find
5:47 male male pair bonds and female female
5:50 pair bonds because when it's not tied to
5:51 offspring then you get a lot more
5:54 variation in who pair bonding with who
5:57 if it's based on defending a resource
6:01 and then in reptile for example the only
6:03 peir bonding reptile is these
6:06 shingleback skinks that we study in
6:08 Australia and it's thought that the
6:10 reason that they do pair bonding is
6:12 actually it interfaces with the immune
6:14 system because there are lots of
6:16 parasites around individuals that pair
6:19 bond and only reproduce with a specific
6:22 individual have less diseases than
6:24 individuals that are a little bit more
6:26 promiscuous oh interesting it's one of
6:28 these things that we take it very much
6:30 for granted as this is the way things
6:32 work in humans and therefore it must be
6:34 the way things work in other animals but
6:36 yeah it's interesting to hear that about
6:38 there being so many different strategies
6:40 well let's dive into some examples
6:41 because your lab studies some very
6:44 interesting organisms uh both in your
6:46 lab and out in the field around the
6:47 world really it's it's very impressive
6:49 looking through your website just to see
6:51 all the different animals the different
6:52 parts of the world where you're doing
6:54 this research let's start with the
6:56 poison frogs can you describe them for
6:59 us what do they like sure so poison
7:00 frogs have evolved several times this
7:03 like trait of being chemically defended
7:05 and very colorful so they're very
7:07 brightly colored my favorite frog is
7:11 blue with black spots um and so that's a
7:14 male unial care species we do most of
7:16 our work in Ecuador in Colombia and in
7:19 French Guana different species can be
7:21 wildly different colors and even within
7:23 the same species they can have very
7:25 different colorations each population
7:28 has their own little flavor of a pattern
7:31 and eration that they've evolved to
7:33 signal to their predators that they are
7:37 not a tasty snack and all of them
7:39 display parental care but that looks
7:41 different in different species so in
7:43 some species only dads care for
7:44 Offspring and in some species only
7:46 females do this and in others they're
7:49 biparental they're pair bonding they're
7:51 monogamous and they really have to work
7:53 together as a team to successfully rear
7:55 their TD holes just to give you an
7:58 example they lay their eggs in the leaf
8:00 litter they have to get their tadpoles
8:03 after they hatch from the leaf litter
8:05 you know on the ground to a pool of
8:07 water because tadpoles are still Aquatic
8:10 and so they carry them piggyback style
8:12 to a pool of water and then in species
8:14 where Ms are involved they actually come
8:17 back and feed the tadpoles for several
8:19 months until the tadpoles complete
8:21 metamorphosis and so it's this very
8:25 energy intensive parental care strategy
8:26 I was amazed to read about some of the
8:28 studies you've done sort of tracking
8:30 these little fr around the forest as you
8:32 mentioned they're laying their eggs and
8:33 then they've got to take their tpes from
8:34 one place to another and then they've
8:36 got to come back and feed them how do
8:39 you keep track of this Behavior so the
8:42 size of these frogs are very small
8:44 compared to what people would be
8:45 familiar with in a temperate region like
8:48 the United States the monogamous species
8:50 that we study is about like the size of
8:53 your thumbnail and we have two ways of
8:57 tracking them one we use these frog
8:59 pants we call them these like belts
9:02 where we put little trackers on them and
9:04 can track where they are moving
9:06 throughout the forest and this gives us
9:08 a sense of like where their home ranges
9:11 and where they're putting their tadpoles
9:13 they put their tadpoles in these very
9:15 specific plants and the you know to me
9:17 the forest looks all the same and like
9:18 how are they remembering where they're
9:20 putting their tadpole and then the other
9:22 thing that we do is we use these camera
9:24 traps both in the field and in the
9:28 laboratory that are motion activated and
9:32 we put these cameras above the nursery
9:34 sites where the Todd Pooles are living
9:37 and then we can record any parental
9:40 interactions that's so cool okay so what
9:41 are you learning about the brain
9:44 circuits behind parental care you said
9:46 you're interested in understanding the
9:48 differences between poison frogs where
9:49 the mom takes care of the babies where
9:51 the dad takes care of the babies and
9:53 where both take care of the babies so
9:56 what is that teaching us I initially
9:59 thought there would be different brain
10:02 regions and cell types that are
10:04 facilitating parental care in males and
10:07 females but by comparing all this
10:09 species we found that actually there's a
10:13 core circuit a core set of cells that
10:16 promote parental behavior in both sexes
10:19 so for example we have found that these
10:22 ginin neurons in the hypothalamus are
10:25 activated when they do parental care and
10:28 these same neurons are also activated
10:30 during parental care and mammals there's
10:33 this core circuit for Parental care and
10:35 it's the same when you look in a frog
10:37 and when you look in an anal and soble
10:39 yeah so potentially you know each time
10:42 you've evolved parental care the brain
10:46 is using the same toolkit and so now the
10:48 question we have is well what causes
10:51 this circuit to be activated in some
10:53 cases but not others and what are the
10:55 triggers that are turning on this
10:58 circuit and so that's where we're at now
11:00 that's so fascinating I was really also
11:02 interested in the work you did about
11:04 feeding the eggs I mean in mammals
11:07 parenting is closely tied to nursing you
11:09 mentioned that in some of these frog
11:11 species they also feed the babies their
11:14 own unfertilized eggs why do they do
11:15 that and and what did what did you find
11:17 about the brain circuits is it similar
11:20 to in mammals with nursing yeah so we're
11:22 very interested in how new behaviors of
11:24 all like how do you change brain
11:27 circuitry to invent a new behavior in
11:30 the case of mammals and ation and like
11:31 infants crying to their mom and things
11:33 like that these are very ancestral
11:35 features of mammals you know that all
11:38 mammals share and so we want to
11:40 understand like how does that arise like
11:43 how do you invent a new behavior that
11:45 requires moms and Offspring to
11:48 communicate with one another and so we
11:50 started studying the evolution of this
11:53 egg feeding behavior in that system moms
11:56 visit the tadpoles and then the tadpoles
11:58 have to communicate that they need food
12:00 and they do it with this dance display
12:02 called begging Behavior this has evolved
12:05 many times in frogs and so it also let
12:07 us look at when you evolve a new
12:09 Behavior do you always do it the same
12:12 way in this case we were comparing
12:14 poison DRS in South America and poison
12:15 DRS in
12:17 Madagascar and what we found is that the
12:19 behaviors were very similar and then the
12:21 brain regions that were promoting this
12:23 Behavior were the same but when we
12:25 started looking at different cell types
12:26 and signaling Pathways they were
12:28 actually very different between species
12:31 so for example the Madagascar frauds
12:34 seem to use the oxytocin system similar
12:37 to mammals to promote maternal care
12:39 whereas South American poison frogs
12:42 don't and so it suggests that there's
12:45 this alternative mechanistic solution to
12:48 promoting maternal care in the South
12:52 American species interesting so um the
12:54 last thing I want to ask about frogs and
12:55 I I do want to touch on a couple of
12:57 other of the animals you're studying
12:59 briefly is I was really interested to
13:01 see you've got um a new study that
13:04 you're working on showing that some of
13:05 the frogs that that do have pair bonds
13:08 that do have long-term bonds seem to
13:09 have empathy for one another could you
13:12 talk about that a little bit yeah so
13:16 what we were interested in is this idea
13:19 that the strength of a pair bond in some
13:23 way depends on your ability to empathize
13:25 with your partner the ability to see
13:27 when they're stressed the ability to
13:29 pick up a little bit of slack when
13:30 they're not feeling well and this
13:32 ability to kind of be flexible in the
13:34 amount of work that you're putting in
13:36 and kind of in tune to your partner's
13:38 you know State and so this has been
13:41 shown in mammals and birds but we also
13:43 wanted to test well you know these frogs
13:46 do monogamy they do pair bonding so it's
13:47 you know it's probable that they can
13:51 also do this Behavior what we did is we
13:54 ended up replicating a study in mammals
13:56 where they take one of the partners and
13:59 they stress them and then they unite
14:01 them and then they look to see what are
14:04 the behavioral and hormonal responses of
14:06 their partner and so what we found is
14:09 that in frogs and similar to mammals
14:11 whenever the partner is stressed the
14:14 focal animal will then mirror their
14:17 behavior and their hormone levels so if
14:18 their partner is stressed and they have
14:21 high cortisol levels they will also have
14:22 increased in cortisol levels even though
14:24 they were not exposed to a stressor and
14:27 we found that the partner's ability to
14:29 do that kind of predicts their their
14:31 bond strength and how good they are at
14:34 rearing Offspring oh that's fascinating
14:37 yeah it has real Fitness outcomes in
14:40 these frogs and I think that for a while
14:43 and I was guilty of this too when we
14:45 first started this project is because
14:47 you know we most of us have a very
14:49 mammal Centric view of empathy but you
14:52 know even Darwin hypothesized that
14:54 empathy was very widespread across the
14:56 animal kingdom and you know in a way
14:58 that he was right that even these frogs
15:00 are able to mirror their hormone and
15:03 their behavioral state to ensure their
15:05 offsprings survive and so I think it's
15:08 something that through natural selection
15:10 has occurred in many different taxa and
15:13 we just haven't looked very broadly to
15:15 find it it's so interesting to hear
15:17 about what we're learning from from
15:20 these frogs about the brain circuits of
15:22 pair bonding and the Brain circuits of
15:24 Parental care and how some of these
15:26 things are are shared the other species
15:28 I wanted to ask about are the wolf
15:30 spiders I think the only thing I know
15:31 about spider parenting probably comes
15:33 from Charlotte's Web and it's a sad
15:36 story so these wolf spiders are they are
15:38 they good parents yeah a wolf spiders
15:40 are amazing parents they do something
15:43 very similar to the poison frogs where
15:46 the moms will carry the egg saat for a
15:48 several weeks and then when the
15:51 spiderlings hat out of this egg saat she
15:53 will actually carry them around on her
15:56 back again for several weeks and during
15:59 this whole time she is not eating she's
16:03 only doing this parental care eventually
16:05 then the spiderlings will disperse once
16:07 they're big enough to kind of make it on
16:09 their own and then she then goes back to
16:12 eating and trying to like regain some of
16:14 these nutrients and all the energy lost
16:16 from this very intensive parental Care
16:17 Effort and so if you think about you
16:19 know the life of a spider caring for a
16:22 clutch for a month without eating is a
16:26 huge investment in their offspring and
16:28 so what we're interested in is like how
16:31 this Behavior that's very similar to
16:32 parental investment we see in vertebrate
16:36 tax how does this work in the brain and
16:37 so we're doing a lot of similar studies
16:39 where we're looking at what are the
16:41 brain region and what are the neural
16:44 cell types that promote parental care in
16:46 wolf spiders there's a lot of variation
16:49 across species on how long they care for
16:51 Offspring and and what that actually
16:52 looks like and I think it's a really
16:54 great comparative system yeah I never
16:56 knew that spiders could be such good
16:59 parents so that brings us
17:00 sort of back to where we started
17:03 thinking about what is the purpose of
17:06 Parental care what is the purpose of
17:08 pair bonding and hearing about all these
17:11 different species I'm struck that there
17:14 is no one answer even though there might
17:16 be common brain circuits that we
17:19 remarkably share with frogs or fish or
17:21 even spiders maybe we'll find out I
17:23 guess they've got very different brains
17:25 the reasons that that animals do parir
17:27 bonding are very different what are your
17:30 takeaways of what learning about our own
17:33 brains and how we do parental care and
17:35 does studying these animals give you a
17:38 different perspective about our own
17:40 experiences as parents or mates or
17:43 Partners yeah I I think it shows that
17:47 being a parent and being a partner is
17:50 one really hard and not something a lot
17:53 of organisms can do well and it takes a
17:56 lot of energy and it takes a lot of
18:00 empathy and really great communication
18:02 and I think this is what we've learned
18:05 in many of the species that we're
18:08 working with being empathetic and being
18:11 in tune with your partner or your child
18:14 like emotional state predicts like the
18:17 strength of that Bond and the ability
18:20 for kids or The Offspring to survive and
18:22 and to do really well those are the
18:25 parallels that I see between the animals
18:28 that we're studying and in my own life
18:29 that's beautiful yeah I mean the
18:31 struggle is real but we're not alone I
18:33 kind of like that right and it's
18:36 something that all different species are
18:39 investing in and making a priority well
18:41 this is so fascinating there are so many
18:42 more really interesting studies and
18:44 different animals and experiments going
18:45 on around the world that your lab is
18:47 doing I'd love to come back and talk
18:49 about this more so thank you so much for
18:51 coming on the show thank you so much for having
18:54 having
18:56 me thanks so much again to Our Guest
18:59 Lauren oconnell for more info about her
19:01 work check out the links in the show
19:04 notes this episode was produced by
19:05 Michael Osborne with production
19:08 assistance by Morgan huker Amy Garza
19:11 designed our artwork I'm Nicholas Wier
19:12 see you next [Music]
