Beetle Mania

Dr. Biology:

This is Ask A Biologist a program about the living world. And I'm Dr. Biology. To start this episode, let me welcome you to another in a series of shows recorded at the Society of Integrative and Comparative Biology Conference. That's usually referred to as SICB.

Now, from the title of this episode, you would naturally expect it to be about beetles, not the Beatles, as in BEATLES the rock band or the popular car from Germany that, well, probably got its nickname because of its beetle shape. In this case, the show is about good old-fashioned insects you can find in your backyard the playground or park as well as many other places. We're also not going to talk about just one beetle, not two. But instead, we need three beetles for this story. It's a tale about the brain, the beetle brain, and how it is evolved for these insects.

To be fair, this is a bit of a prequel for the story because this work is just beginning. The scientist who is investigating these tiny insect brains is Jessleen, well, she goes by the name Jess Kanwal, a neurobiologist and postdoctoral scholar at Caltech. She is one of the researchers in the lab of Joe Parker, who is looking into the curious case of these beetles and their relationship with ants. Oh, and as a bonus, we also talk a little bit about another insect and the game we have on the Ask A Biologist website that teaches you about their communication dance. That's right. They use dance to communicate. Now, let's head over to the conference and get the story behind these beetles.

Dr. Biology:

Welcome to Ask A Biologist, Jess.

Jess::

Thank you. It's so nice to be here.

Dr. Biology:

We have had a fun field few days.

Jess:

Absolutely.

Dr. Biology:

And I am having a great time learning from the different scientists that have come to this conference. All of them are focusing in a few areas, but typically it's animal communication.

Jess:

Yeah.

Dr. Biology:

Animal communication slash movement.

Jess:

Yep.

Dr. Biology:

Animal communication slash movement. Slash. How's the brain work?

Jess:

Exactly.

Dr. Biology:

You are one of these scientists.

Jess:

Mm hmm.

Dr. Biology:

And your subject, though, isn't a lizard, isn't a snake, isn't a butterfly. I'm trying to think of all the others that we've had through here. You're working with beetles?

Jess:

That's right.

Dr. Biology:

What kind of beetles?

Jess:

So, we study a very small beetle called rove beetles. And they don't look like your typical ladybug beetle. So, these beetles have evolved to actually have a very flexible posterior end. So, we call this the abdomen. And the abdomen can actually bend and flex forward and release toxic chemicals that can attack other insects like ants. Yeah. So, these beetles are very small, about two millimeters. They are typically like dark, brownish in color.

And you'll see them crawling through the dirt. They can fly a little bit, but they are mostly soil dwelling insects. And they have to interact with all the other insects that live in the world. Right. So, big ants, big crickets, other small larvae, which they like to eat And so we're interested in how they interact with all these other species in the world.

Dr. Biology:

Luckily, they're small.

Jess:

Yeah.

Dr. Biology:

I can see one really large. You know, when you think about movies like Ant-Man and things like that, when all of a sudden, we've shrunk down to their size or they're increased to our size, that trick with the abdomen. That one gets me there so they actually can turn it around.

Jess:

It actually curves up.

Dr. Biology:

So, they basically have their phaser up on top.

Jess:

Yeah.

Dr. Biology:

And the chemicals, they actually shoot them out?

Jess:

Basically. So, they have these chemicals, they're called benzo Quinones and they're very toxic. So, whenever they encounter like an ant, which would normally attack the beetle, and the ants are much bigger, so they can easily get the beetle, but the beetle comes up, bends its abdomen towards the ant, shoots out these toxic chemicals, and the ant, you can literally see it kind of step back. It starts to rub its face and it pauses. And that gives the beetle just enough time to escape in the opposite direction.

Dr. Biology:

Oh,

Jess:

So, it's got this amazing chemical defense system that has allowed it to evolve and live in this pretty, you know, scary world for a little beetle that's encountering all these other big insects whenever it's moving around.

Dr. Biology:

Right. And did you see there brown in color?

Jess:

Yeah, they're brown and black. And you can imagine that that kind of helps them camouflage with the dirt and the soil that we find them in.

Dr. Biology:

And the size, you know, you said smaller than an ant. And of course, there are lots of different ants. Some are really, really tiny. And so. So how big would they be?

Jess:

Yeah, I mean, I would say the beetle is probably half the size of a grain of rice maybe.

Dr. Biology:

Really tiny.

Jess:

Very tiny. If you've seen fruit flies like flying around on your fruit in your kitchen, they're about the same length as that. Maybe a little bit longer, but they're very skinny. And then you know, an ant, I would say the ants that they typically encounter are a little bit larger. So, you know, maybe the size of the grain, basically two to three times larger than the beetle itself. Right.

Dr. Biology:

Sounds scary to me.

Jess:

Yeah, it is. I mean, it's a scary world for a tiny little beetle like that.

Dr. Biology:

Well, let's talk a little bit more about this beetle.

Jess:

Yeah,

Dr. Biology:

It has more for us to learn about than just its defenses.

Jess:

Absolutely.

Dr. Biology:

All right. What are you learning about this beetle?

Jess:

So, what's very interesting is that I actually want to bring up another beetle species that's related to the one I just described.

Dr. Biology:

Oh, you just got me started on this one, and now we're going to go to another one.

Jess:

Yes. And it's it's really cool. And it's related to your question, I promise.

Dr. Biology:

Okay.

Jess:

So, what's very interesting is this beetle has evolved over time, and there are other species that have evolved to not attack ants, but to live with the ants. And so, you know, I can get into more details about how that works. But what we're interested in is how has the neurobiology of the beetle, how has their brain and all of the sensors that help them smell, taste, touch, see? How have all of those things changed over evolution to make them suddenly go from attacking ants and running away to living inside of the ant colony?

And interacting with ants all the time? And so that's kind of the big question that we're interested in understanding. But the lab is fairly new and so we're still very early on in this process. But we hope that by starting and studying the behavior of these beetles, the ones that attack the ants, the ones that live with the ants and other species as well. We hope that we can understand what are the different behavioral changes that have occurred and how do they then correlate to changes in the brain that allow for the different behaviors to emerge.

Dr. Biology:

Right. So, we've gone from predator prey.

Jess:

Umm huh

Dr. Biology:

To a mutualistic is a word.

Jess:

Mutualistic.

Dr. Biology:

Symbiotic relationship. Where they both benefit, I'm assuming. So now let's talk about the benefits here before we get into the brain. And here, what's the benefit for this beetle and for the ants?

Jess:

Yeah, so that's a great question. So, we know that the benefit for the beetle is that they actually get to eat the ant brood, which is basically the ant babies. So, the ant larvae. So not a very nice thing to do, but that is their intention. That is one of the things they benefit from by being part of the ant colony. They also get protection. So, you know, imagine now you are living in this, you know, huge society of thousands of ants and they are essentially protecting the beetle because they don't actually know that it's a beetle. So that's where a little trick comes in that the beetles actually use what we call chemical camouflage to get inside of the colony.

Dr. Biology:

So now you're getting to the bottom of this mystery. And that's the fact that ants really don't have great vision.

Jess:

Exactly. At least not the species yet.

Dr. Biology:

And so they rely on chemical communication.

Jess:

Yes.

Dr. Biology:

So, in this case, we've got beetles that are pretending.

Jess:

Mm hmm.

Dr. Biology:

Mimicking

Jess:

Yep.

Dr. Biology:

that chemical or actually maybe reproducing it exactly. I don't know. Have you checked, have you tested the chemical is it exactly the same?

Jess:

Yes. So, this is the interesting part. So, the beetles, once they enter the ant colony, they will actually climb onto the ants. They'll use their mandibles, which are kind of like their mouth jaws grip onto the ant antennae or different parts of the ant leg, basically the ant body. And they will groom the ant so they will take their legs. They'll rub them on the ant and then they'll rub it on to themselves. And what they're doing is they're transferring these chemicals that are on the ant, on the cuticle or the skin of the ant onto themselves.

Dr. Biology:

So, they're not making the chemical themselves.

Jess:

Right? They're not making the Beatles are making it themselves. They're transferring what we call cuticular hydrocarbons, these chemicals on the ant onto themselves. And so, they are basically taking the smell of the ant and putting it on to themselves.

Dr. Biology:

Rubbing. It all over.

Jess:

Yeah, exactly. Yeah. Yeah.

Dr. Biology:

So, does the grooming give them any kind of benefit?

Jess:

So, this is what we don't really know, and we don't have any evidence at the moment that suggests it does, which is why this kind of seems more like a parasitic relationship.

Dr. Biology:

Right. I was just going to say, well, so much for mutualism and the symbiotic relationship.

Jess:

Yeah. Yeah, it is still you know, considered symbiosis. So, a symbiosis is anytime you have interaction between different organisms. But just like you were.

Dr. Biology:

Saying, it's just not a beneficial one. And if it's parasitic. Right. Okay.

Jess:

Exactly. Yeah. Yeah. So, we think right now that it's more of a parasitic relationship, but we're leaving it open because no one's studied the ants. And so, we don't know to what extent the ants, if at all, benefit from the beetles. It's possible that the grooming of the beetles cleans off other bacteria on the ants could potentially be beneficial for the ants as well.

Jess:

But we just we don't know yet.

Dr. Biology:

All right, so you took my first beetle away and replaced it with the second one. All right. And you said you promised you would tell me a reason for doing this.

Jess:

Yes.

Dr. Biology:

We were talking about you want to learn about what's the evolutionary process that might have occurred. I guess my first question is, are these two beetles related? Are they?

Jess:

Yeah.

Dr. Biology:

Okay.

Jess:

Yeah, they're pretty closely related. They're both rove beetles. And so, our lab studies actually many different rove beetle species. These are the two that we're most interested in because they kind of lie on the opposite ends of the spectrum. But I'll tell you one more beetle species and then I won't add anymore.

Dr. Biology:

Man, we just went from one to two. Now we're going to go to three. Okay.

Jess:

But no more after that. So, this third species lies somewhere in between the two that I just described. In that it will live outside of the ant colony, but just on the peripheral edges of the ant colony. So, what's interesting is that this other species attracts the ants. It releases a compound called an appeasement compound. We don't know exactly what that is.

And the ants will come over and they'll start feeding from it. And so, the ants really like this beetle. They won't attack it. But this beetle still has the chemical to release and attack the ants, that toxic benzoate and chemical. So, it's kind of in the middle in that it can attack ants. And sometimes very rarely it does. But most of the time, it just hangs out in the periphery and the ants come over, they feed on it and they don't attack it.

Dr. Biology:

So, is there some benefit for being close to the ant colony, even if they're not in it? So, there's a little bit of protection.

Jess:

Yeah, that's a really good question. We don't know exactly what that is, but your hypothesis sounds right on. So, we think that there might be some protection still, but we don't know exactly what their reason is.

Dr. Biology:

All right. So, we have three beetles.

Jess:

Yeah. Three beetle species.

Dr. Biology:

One armed and ready to attack.

Jess:

Mm hmm.

Dr. Biology:

One that lives in the colony.

Jess:

Mm hmm.

Dr. Biology:

Right. And that one, does it also still produce the chemical to attack or no longer?

Jess:

No. So that one no longer produces that chemical.

Dr. Biology:

Okay. And then we have the one in the middle.

Jess:

That's right.

Dr. Biology:

And it has the ability to attack but doesn't attack.

Jess:

Mm hmm.

Dr. Biology:

And is able to still live close to the colony without becoming a meal.

Jess:

Exactly. Yeah.

Dr. Biology:

Okay. All right. We have the behaviors.

Jess:

Yeah.

Dr. Biology:

So now how are we going to study the brains?

Jess:

Yeah, so that's a great question. So, a lot of times in studying the brain we start by thinking about what are the different sensory modalities, the different senses that the animal uses. And how do those change? Because when we're first taking in the world, everything comes in through. For humans, our five senses smell, taste, touch, sight, and sound. And of course, there are actually way more senses in that. You might think of temperature, humidity.

But with insects, they also have many sensory modalities. And unlike us humans, which really focus on vision insects, as you mentioned, Dr. Biology, focus on chemical senses. The smell and the taste a lot. And so, we start by understanding the brain, by looking at how they sense the world through, in particular, chemical senses. What are they smelling? How are they smelling it? How is that helping them orient and navigate towards another insect or away from another insect?

So, we are starting by looking at how has their smell system changed across these different beetle species. And we're trying to compare how has the number of smell sensors that they have in their antennae, which is kind of equivalent to their nose. How has that changed across these different species? And then we want to go deeper into the brain and we want to start to record the neural activity of these different brains. And start to see if I give them an ant. How does that one species that normally attacks ants, how does its brain respond versus the other species that lives with the ants? How does its brain respond?

And so, by using this comparison method across the different beetles, we're hoping that in the future we can really start to understand what's changing in the brain, how is it changing and how does that lead to that completely different behavior towards ants?

Dr. Biology:

So, all sounds great. My mind is going all right. I have a beetle that's smaller than a grain of rice.

Jess:

Huh.

Dr. Biology:

So, I've got a really, really tiny brain.

Jess:

Yeah.

Dr. Biology:

How am I going to look at that brain how am I going to study that brain?

Jess:

Yeah.

Dr. Biology:

What are the tools?

Jess:

Yeah. Great question. So, first of all, a lot of people sometimes even ask me, do they have a brain? And it turns out they do. It's very small, but a lot of insects have what we call a central nervous system. So that's the brain in their head. And then they have a central nervous system, which is equivalent to the spinal cord, and that's in their body. And so, we start by looking in the brain in their head, ans to do that, there are tools where we can actually genetically insert a fluorescent molecule into neurons in the brain.

And what's really amazing about this is that this fluorescent molecule will change its shape when the neurons become active. And so, as the neurons are becoming more and more active, the molecule changes its shape and it starts to glow just like, you know, you might see glowing stars it'll start to glow typically green in color. And we can use a microscope, put this tiny little insect under a microscope and pick up those green photons of light that are being emitted when the neural activity starts to get more and more active.

And so, this is how we can start to look inside that tiny little brain, which is so small, you can only really see it under a microscope and start to see how different neurons are lighting up and responding to different sensory cues in the world.

Dr. Biology:

Hmm. I have visions of this. Do we have movies or pictures of this?

Jess:

Yeah, there is lots of pictures. I don't have them in the beetles yet because we're still working on genetically inserting these molecules. But you can imagine, you know, I used to do this in fruit flies as well. And so basically, my day-to-day life as a scientist would be go into a dark microscope room and I would turn on the computer, put the flies or the beetles under a microscope.

Jess:

And basically, on my screen, I just see these beautiful flashes of green light as it's traveling through the nervous system of the brain. And it's really, really fun to watch. So, you know, it's every day you see, basically the brain is talking to you because this is how the cells are communicating with each other. And as a scientist, we're always trying to figure out what are they saying to each other, because obviously they don't speak the same language as us. But we want to know how are they communicating to each other and how are they interpreting the different worlds that they are seeing?

Dr. Biology:

Well, we are moving our podcast to a new service, and we've added, even though we've always had chapters for our listeners to go to certain sections of the show. But the newer ones now allow us to put an image with the different cell.

Jess:

Oh, great.

Dr. Biology:

So, for those listeners that are using the podcast apps that allow you to see that, we'll get some of those images.

Jess:

Yeah, definitely.

Dr. Biology:

Put them in there and they'll be able to see them.

Jess:

Yeah, absolutely.

Dr. Biology:

And if not, we'll put some links in the show notes and in the transcripts, so we'll make sure people can get to it.

Jess:

Perfect. Yeah.

Dr. Biology:

All right. So, you're in the early stages of this.

Jess:

Early stages, yeah.

Dr. Biology:

When do I have to check back?

Jess:

Check back next year. Maybe that next SICB. We'll find out. You know, this work is a bit slow. We're starting to work in an organism that very few other people study in the whole world, and no one's looked into its brain before. So, there is a lot of early groundwork that we have to do. So, yeah, check back in another year or so.

Dr. Biology:

From your work with all the different animals.

Jess:

Mm hmm.

Dr. Biology:

And the main focus has been the brain neurons.

Jess:

Yeah.

Dr. Biology:

Is there anything that surprised you? I mean, something that just really you didn't expect.

Jess:

Hmm. Yeah. So, there's been a lot of surprises I think the biggest one is just how smart and amazing tiny little critters like insects are. When I started, I had no idea that, for instance, bees do an amazing dance to communicate with each other and all of that is being coordinated by their brain and how their brain is doing that is still a huge mystery. One that I'm super interested in but, you know, I didn't know that. I didn't know that insects could see ultraviolet light and that they could sense odors and smells in the world so much better than we can. So, I think at every step with every organism, and animal that I've looked at, I've just been even more fascinated by how amazing these creatures are and how they navigate and live in the world.

Dr. Biology:

It's interesting you bring up the bees because we have a large group of researchers at ASU that are all focused on bees.

Jess:

Oh, awesome.

Dr. Biology:

One of them is Brian Smith does a lot on brains.

Jess:

Yeah.

Dr. Biology:

Bee brains and his support on Ask A Biologist has allowed us to build a game called The Waggle Dance.

Jess:

I did that game. It was really good. Yeah.

Dr. Biology:

What's interesting about it, there's a beginning level and an advanced level, and there's a good thing because I'm telling you, those bees are pretty good at what they're doing because I had to start at the beginning level to be able to get to the advanced.

Jess:

I know. Me too. I had trouble with the advanced one, and I knew about what the bees do. Right.

Dr. Biology:

So, if you go and play that game, in essence, when you see a video of a bee doing a waggle dance, you actually would understand basically what they're saying.

Jess:

Yeah.

Dr. Biology:

To the other sister bees, right. Where a particular flower is.

Jess:

Yeah.

Dr. Biology:

And that's pretty amazing. It's kind of like you could be Dr. Doolittle.

Jess:

Yeah. It's fascinating. And not only where the flower is, like, what is the quality of that flower? Does it have a lot of nectar or not? Like, that's just crazy that they can do that and they have their own language that they're using to communicate with each other that, you know, we had to spend years and decades to just uncover and understand.

Dr. Biology:

All right. Well, Jess: nobody gets to leave. Ask a biologist without answering three questions.

Jess:

Oh, okay.

Dr. Biology:

You know, all set

Jess:

Already.

Dr. Biology:

Okay. The first one is, do you remember when you knew you were going to be a scientist?

Jess:

Who you know, for me, I think it was something that was very gradual. I don't think there was a single moment where I knew for sure that this is what I would definitely want to do. But there were definitely some moments that sparked my interest so much that got me so excited that, you know, as they contributed over time, they all added up. And when I looked back, I realized, yes, this is definitely what I want to do.

And I would say the one of the main ones I remember was as a high school student, I was studying neurons in a cell culture. So, these are neurons that are plated into a little petri dish. And I was looking at them under the microscope. And it was the first time that I was looking at brain cells under a microscope. And they were just so beautiful. It was like looking at a constellation of stars.

They were fluorescing - glowing different colors because we were trying to study different proteins and molecules that were inside of these cells. So, we had blue and red and green. I was just kind of scrolling through this amazing starry night sky. But really it was neurons in the brain. And so that was one of my first and favorite memories.

Dr. Biology:

Right. I guess we could call it brainy nights.

Jess:

Brainy nights. Perfect. Yeah.

Dr. Biology:

All right. The next question is where I get a little bit devious.

Jess:

All right. All right, I'm ready.

Dr. Biology:

It's also can be playful. Depends on how you take this. I'm going to take all of your science away from you.

Jess:

Okay.

Dr. Biology:

You've done a lot of work. You've gone to school, and obviously, I'm not really taking it away from you. [laughter] It's just. This is just a mental exercise. This is a brain exercise. All right? What we're going to do is we're going to take all your science away. Most of my scientists like to teach as well, so I like to take that away.

Jess:

Oh, no.

Dr. Biology:

Because I want you to think about what would you be or what would you do if you could be anything and you couldn't be those two things.

Jess:

Oh, that is really tough. So, I really love working with kids. This maybe isn't too fair because you took away my teaching, but I do really love playing with children. And so, if I couldn't be a scientist and if I couldn't teach at all, which is a huge part of what I do, and what I love to do, I'd love to work with kids and just help them see the world be outside in nature. Well, I don't know exactly what that would look like. Maybe going on nature trips with students, with kids and getting them excited about the outside world.

Dr. Biology:

Going to be a camp counselor?

Jess:

Yeah, yeah. Maybe something like that. You know, if you hadn't taken away everything my answer would have been to go around teaching Science Summer camps to kids. But I think that's probably not fair, given what you took away.

Dr. Biology:

You could do Outward Bound or something like that, where you could literally go backpacking with students.

Jess:

That would be so fun. I would love that because I love I love outdoors. I love hiking and photography and working with kids. So, if I could combine all three of those with something like a camp counselor or Outward Bound, I think that would probably be my other career.

Dr. Biology:

All right. Fair enough.

Jess:

All right.

Dr. Biology:

It'd be fun.

Dr. Biology:

Yeah.

Dr. Biology:

I'm sure kids would love it, too.

Jess:

Yeah, I hope so.

Dr. Biology:

Last question.

Jess:

All right.

Dr. Biology:

What advice would you have for a future scientist? Those kids that are growing up, maybe listening to this podcast, loving your stories about the brainy nights. Your amazing beetles, all three of them that you brought me into. I thought I was starting with one and ended up with three. What advice would you have for them?

Jess:

So, I would say to try and follow whatever you find the most interesting and whatever you're most curious about, because you never know where it's going to take you. I started by looking at little neurons in a petri dish and somehow over the course of my career, I've got the opportunity to study bees and salamanders and flies and now beetles, and it's super exciting. So just follow that interest, that passion. Sometimes you may not know what it is and that's okay. Just whatever seems like it's that very interesting in that moment. Follow that question and ask a lot of questions.

And I think most importantly, don't be afraid and don't worry when you fail, because that is a huge part of science. And you only come out better from that when you fail, and you try to figure out why you were wrong and how to do better next time. That is the best learning experience there is. So, a lot of science is going through those failures and coming out on the other side. But when you're excited and really interested about the questions and the world you're trying to understand around you, getting through those failures can be a lot easier

Dr. Biology:

Marvelous.

Jess:

Yeah.

Dr. Biology:

Yeah. Learning through mistakes. I've had many.

Jess:

[laughter] Yes. I think we all have. I've certainly had a boatload of them, and I expect to have many more in the future. But it's okay and it's good to get through.

Dr. Biology:

Well, Jess, thank you so much for joining me on Ask A Biologist.

Jess:

Yeah, thank you. Dr. Biology is super fun chatting with you.

Dr. Biology:

You've been listening to Ask A Biologist. My guest has been neurobiologist Jess Kanwal, a postdoctoral scholar at Caltech who's exploring the world of beetle brains. If you want to follow her work on Twitter, she has the envious title handle @BrainExplorer.

For this episode, we plan to include a collection of links and images in the show notes and transcripts so you can see and explore more about these curious beetles and their brains. If you're listening to this podcast on a mobile app that allows you to see our chapter link and images, we'll include them there, too. And we'll also be sure to include links to our Bee Waggle dance game and its companion story, Bee Bonanza. So be sure to check that out.

The Ask a Biologist podcast is usually produced on the campus of Arizona State University and is recorded in the Grassroots Studio housed in the School of Life Sciences, which is an academic unit of The College of Liberal Arts and Sciences. But for this show, we're at the annual Research Conference for the Society of Integrative and Comparative Biology. And remember, even though our program is not broadcast live you can still send us your questions about biology using our companion website. The address is - askabiologist.asu.edu, or you can just Google the words. Ask A Biologist.

As always, I'm Dr. Biology, and I hope you're staying safe and healthy.