Hello, and welcome to Ask a Scientist, the podcast for kids, and adults, of course, to ask scientists questions about anything they want to know. There are so many scientists out there doing so much cool scientific research. In the news, we’re constantly hearing about scientists and their new ideas and where those ideas are going to take us in the future. But just who are these scientists? In this podcast, we will learn a little bit more about who they are and what inspires them as scientists. I’m your host, Victoria Crystal. Every other week, I’ll sit down with a different scientist, and ask them questions written by you, the listeners, and by students from classrooms throughout the country.
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Victoria:
Hello listeners! Welcome back to the next episode of Ask a Scientist. Our guest today is Dr. Gussie Maccracken. She is a paleontologist and National Science Foundation post-doctoral fellow specializing on how plants and insects interacted in the fossil record.
Gussie, thank you so much for being here today.
Dr. Maccracken:
Thank you Vikki for having me on your show. I’m so excited to get to talk with you about my research on insect damage on fossil leaves.
Victoria:
Awesome. Well, I, and I’m sure the listeners are so excited to hear all about it. Before we get to the questions, do you want to just explain a little bit about yourself and your work and some of your current projects?
Dr. Maccracken:
Absolutely! So, I specialize in looking at the types of damage that herbivorous insects make on plants in the fossil record. So whether that’s the holes that they’re chewing in the leaves, or maybe even galls or leaf mines. I try to figure out either what kinds of insects made the damage in the past, or perhaps things like how intense damage in ancient ecosystems was. And this can tell us a lot about ancient ecology, and it can tell us about what kinds of insects were around in the past, because the damage that insects make is often way more abundant than the actual fossils of their bodies. Since insects are pretty squishy and they take very specialized environments to become fossils. So, so we kind of use insect damage on fossil plants as a good indicator of what kind of bugs were around in the past.
Victoria:
(Did the insects look different than today?)
That is awesome. Well, we have so many questions about insects of the past today, and all of these questions were written by fourth grade students from Bromwell Elementary in Denver, Colorado.
And we will get right into these questions with this first question: did the insects look different than today?
Dr. Maccracken:
That is a great question. So insects in the past have looked different than they look today, in some ways, but in other ways, not so much. So, in the Carboniferous, around 350 to 300 million years ago, insects for actually most of them are much larger than they are today. And we would get things like giant dragonflies that had up to a three-foot wingspan. And so we get these kind of familiar looking insects, but they would just be at a scale that we’re not really used to today.
Victoria:
(Were there giant insects back then? How big did they get? (Another question was specifically about big dragonflies.) What was the biggest bug back then? Were there big enough flying insects so you could ride them?)
That is so cool.
Our next question builds really well on that. The students want to know how big did these big insects get, and what was the biggest bug back then? And then also, this is a very fun part of the question: were there bugs big enough that you could ride them?
Dr. Maccracken:
Well, I would not try or ride any of these bugs. I don’t think they would be able to support you, and you might end up squishing them.
But they did get extremely large in the Carboniferous. One of my favorite ancient creatures was this millipede like animal, called Arthropleura. And so imagine a millipede, but imagine it’s about seven feet long. And it’s just crawling along the floor of a forest. You know, I’d love to think back into time and think that there was a time on earth when millipedes were, you know, longer than most humans are tall. I mean, these were enormous critters.
Victoria:
(How did they talk or sound or make noise? What sounds did they make?)
Oh, wow. Giant millipedes. That would be crazy.
This next set of questions is about these giant insects making noise. And so the questions are, how did they talk or sound or make noise? And what sounds did they make?
Dr. Maccracken:
I love that question. It’s so imaginative. And we have to use our imaginations when we’re looking at these fossil insects, ancient insects, because we can’t actually hear them. And so what we do is we look at their structure. We look at the different kinds of body parts that they might have, and try to infer when we think that insects might’ve started making noise and for what purposes and what they would have sounded like.
So since we don’t know for sure what they sounded like, you know, our best guess is that they sound similar to what insects sound like today. You know, you’d hear that buzzing. You’d hear the flapping of the wings. And we know that things like grasshoppers are really ancient, and because they also have what we call a tympanic ear, structures for hearing, in these ancient grasshopper fossils, we can infer that they probably made that chirping noise, that kind of singing noise that they make today. And we know that they were listening to each other.
And so overall I’d say insects probably are making similar noises in the past as they did today. But, you know, we just, we have to learn more about ancient insects sound to come out with, you know, more detailed response. And that’s one of the cool things about studying fossil insects and also the behaviors of insects, is that there’s a lot of work that still needs to be done. Especially by people like, you know, kids like you that are coming up in our educational systems and choosing, you know, paths, you know, career paths that might one day end up in the sciences.
Victoria:
(Were there mosquitoes or other predator insects?)
Yeah. So if you’re interested, you can read the scientist that figures out how they sounded.
All right, this next question is, were there mosquitoes or other predator insects?
Dr. Maccracken:
There were definitely mosquitoes and other predaceous insects in the past.
One of my colleagues, a scientist who I actually used to share an office with, found a mosquito preserved in amber that had a blood meal, that had blood in its stomach. And so it was just like Jurassic Park. Although he really hates that reference. But you’re not allowed to publish a discovery like that and not see the, you know, the parallel between finding a mosquito in amber with blood and, you know, Jurassic Park which is a movie that, you know, I’m sure a lot of us all, all love and have watched, you know, bunches of times.
As far as other predaceous insects, we think that there were loads of them, because we have insects that are eating plants. And then we also have a lot of insects today that are eating those other insects. And so, things like dragonflies, we know that they are predators today, and that was likely the case in the past.
And so insects have all of these different, what we call niches, all of these different roles in the ecosystems. Some were eating plants, some were eating other insects, some are helping dead things to decompose, and some are pollinating. So there, there are just a lot of different ecosystem services that insects do today, and that insects likely did in the past.
Victoria:
All right. So I have to ask because of Jurassic Park. Is your colleague going to try and clone dinosaurs from the blood of the mosquito?
Dr. Maccracken:
I don’t think so. I don’t think they could recover DNA from that mosquito. They could only see the presence of blood cells of, I believe red blood cells. But you know, maybe in the future, let’s, let’s try to figure it out. In the meantime, we have birds, which are technically dinosaurs. So I guess, you know, we do have, we have some dinosaurs around today.
Victoria:
(Did the insects have homes like beehives or termite mounds? Were the insects loners, or did they have groups or packs? Did the insects have society like the bees?)
Yes, we do.
And speaking of, of different roles that the insects have in the communities, this next set of questions is all about insects living together. The first question is, did the insects have homes like beehives or termite mounds? And were the insects loners, or did they have groups or packs? Did the insects have society like the bees?
Dr. Maccracken:
That is a fabulous question. Yes. Ancient insects are known to have lived in colonies. And this is really fascinating because in fact we’ve found evidence of these colonies because we found little mounds with these very intricate tunnels in them.
A colleague of mine actually described 75-million-year-old insect mounds. And we don’t know if they’re ants or possibly termites, but it’s one of the, it’s some of the first evidence for what we call a sociality of insects, or the socialness of insects. Because in order to have a termite mound or an ant’s nest or a beehive, you know, the insects have to, you know, be, be working together, they have to be getting along. A lot of these mounds are actually very closely, you know, it’s a family unit, they’re very closely related, they’re clones of one another in a lot of instances. And so, there was a point in time, you know, hundreds of millions of years ago, when scientists don’t think that, or we don’t have evidence of social insects. And so the evidence is really more recent, geologically speaking, you know, perhaps within the last a hundred or 2 million years, whereas the whole record of insects, we think goes back, you know, over 400 million years in the past.
So, it’s really, it’s a great question because it’s really interesting to think about how socialness in insects might’ve evolved, in what groups that might have evolved in first.
Victoria:
(Were there massive worms and did their tunneling cause collapses in the ground?)
That is really fascinating.
And speaking of places where insects lived, and how they lived, this next question wants to know, were there massive worms and did their tunneling cause collapses in the ground?
Dr. Maccracken:
That is very funny. I like that question. So, I have to say, I do not know of any terrestrial worm fossils. I’m not saying that they haven’t been described by other scientists, but that’s just not my area of expertise. So I don’t, I don’t know.
But what I can say is that there are enormous worms that live in Australia today, and they can get incredibly long. I’m trying to remember exactly how long they can be. I think they can be up to 10 feet long and when they stretch out, you know, how worms kind of moved by, you know, stretching and being like an accordion a little bit. I think you can actually stretch them longer than 10 feet. And these worms are not so much, you know, thick. They don’t have a huge diameter. But they’re just incredibly long, and that’s how they’ve maintained that size. It’s just being incredibly long. And so I don’t think they actually are really able to move a lot of earth that would cause a collapse, for instance. And, you know, they’re consuming and they’re excreting. And so you don’t get, you wouldn’t get these like big, vast tunnels in the earth that, you know, you’d step onto and, you know, fall down 10 feet or whatever. But you know, perhaps there were, you know, lots of enormous worms in the past or perhaps they were, you know, pretty small like they are today. That’s another question that, you know, you can look into, or you can study it yourself and try to make discoveries.
Victoria:
(Were there any poisonous insects that were around back then?)
Wow. 10-foot-long worms! That’s crazy. But yes, we can have a whole group of, of future fossil worm scientists.
Okay, this next question, again this might be something difficult to tell from the fossil record, but this next question is, were there any poisonous insects that were around back then?
Dr. Maccracken:
There were likely lots of poisonous insects around in the past. You were absolutely right. This is going to be difficult to measure using the fossil record, but what we can do is to look around at insects that we see today and try to plot them on the tree of life, what we would call a phylogeny, and then you might have this whole group of insects that has a certain type of poison. And you might be able to kind of guesstimate hypothesize when that group of insects evolved. And you might hypothesize that that poison was utilized, or those insects had adapted to have that poison in the past.
So it’s really a question where you, you know, you might be able to find something like that in the fossil record, but really you have to look at the earth today, you have to look at the insects that are around today.
And what’s really interesting about insect defense is that they actually can do it in a lot of different ways. And some of it is actually stolen from plants that they eat. So things like the monarch butterfly, when they’re caterpillars, they’re eating milkweed, which is extremely poisonous. It can kill a lot of animals on earth today. And so they’re taking that poison from the milkweed and sequestering it, they’re storing it in their own bodies and using it as a defense for themselves. And so it’s pretty interesting to think about how that might’ve evolved when it could have evolved, and, you know, what sorts of creatures might’ve had that in the past.
Victoria:
(What were the insects called?)
Wow. That is very cool.
All right, this is getting into some of the specifics of insects of the past. This question is what were the insects called?
Dr. Maccracken:
What were the insects called? Well, we are still naming them. There are an unimaginable amount of insects that need to be formally described and classified by paleontologists. But there were called all sorts of things. I mean, in general, we categorize them using mostly, you know, groups that are around today. For instance, the grasshoppers would be in Orthoptera, the order of Orthoptera. And so we use the kind of a taxonomic classification. We use a formal classification scheme to organize and name insects.
And so, you know, fossil insects, you can, if you find a new one, you can name it yourself. There are rules you have to follow and naming them. But you know, if you find, if you find a new fossil insect or any new fossil organism, you can name it. So the names, you know, range from descriptions that are Latin or Greek in origin that described maybe the look of a fossil insect or a fossil plant or a dinosaur or whatever you’re naming. And then sometimes you name them after an important person to you or an important scientist in the field, or sometimes you just have fun with it. For instance, I know a fossil plant that’s named Lebowski after the Big Lebowski or, you know, there are fossils named after Lady Gaga.
So, what are the names of fossil insects? Well, they are, you know, there are so many, they’re incredibly varied, and they’re still happening. And it’s all just down to using the Linnaean taxonomic structure.
Victoria:
That’s awesome. Lots of very fun names. And this isn’t one of the questions, but I’m sure the listeners are curious. Have you ever named anything and what did you name things?
Dr. Maccracken:
Well, I am in the process of naming a fossil plant that dates to about 75 million years ago. So the plant that I’m describing, it was growing in what is today Utah. And this plant is about 75 million years old. And so it was growing in this really lush ecosystem where there are large dinosaurs, you know, trumping about. There are loads of different insects flying around and other kinds of vertebrates that are, you know, turtles and crocodiles and all sorts of things. And it’s growing in this swamp essentially. And we named it Kitula gettyi. And Kitula basically the root of it is for a puppy, and it’s the puppy of our friend, Mike Getty. And that’s where we get the word gettyi. And Mike Getty was a really wonderful friend and colleague who was at the Denver Museum of Nature and Science as the fossil preparer, and sadly, he passed away. So we named it in honor. We named this fossil plants in honor of Mike and his puppy Javalina.
Victoria:
Oh, that is really wonderful.
Dr. Maccracken:
Thank you.
Victoria:
(Did the insects pollinate plants back then?)
Okay. And speaking of plants, the next question is, did the insects pollinate plants back then?
Dr. Maccracken:
Insects did pollinate plants in the past. This is a really kind of fun part of the field that I studied. Because you can look at the structures of plants and hypothesize that there were insects pollinated, and you can also look at insect body fossils and try to find grains of pollen on their bodies and also in their gut contents or their stomach contents.
And so there’s great papers out there describing, for instance, beatles trapped in amber that are covered in pollen, or have pollen in their stomachs. And so you can hypothesize that right before the beetle was trapped in amber and died, it was actually moving from flower to flower.
And it’s also kind of fun to think about pollination, not just to flowers, but of other kinds of plants in the past. So up until about 140 million years ago, there were no flowering plants. And pollination happened on things like conifers or, you know, what are similar to pine trees today, a group called the cycads. And so we actually look at different structures on these ancient plants and, look at the mouth parts of ancient insects, and we can hypothesize about how they were being pollinated by insects.
Victoria:
(How many other insects that were around back then are still around today?)
That is so awesome.
Okay, this next question is how many other insects that were around back then are still around today?
Dr. Maccracken:
That is a fantastic question. And it’s a hard one to answer. But, we know that based on the fossil record, a lot of the major groups of insects that were around, say in the Jurassic period between 200 and 145 million years ago, a lot of those major groups, those families of insects, are still around today.
There are some lineages of insects that have gone extinct in the past. There’s one with the, I know a funky name, palaeodictyoptera, which was a clade of insects that had kind of mosquito-like mouth parts that they would use to stick into plants and suck out the juices and all the nutrients. When you see them a lot in very old fossil deposits in the Permian and in, you know, 275-million-year-old deposits. And we know that they went extinct, and we don’t see them anymore today.
But a lot of insects are actually still around today. Maybe not the identical species, but the lineages of insects have made it through to today. You know, if we think about big things like, dinosaurs or some of the very early mammals, like they looked much different in the past and they went to extinct and then new things kind of rose up to prominence. But within insects, you know, they’re incredibly abundant, they’re incredibly diverse and they just haven’t changed through time too much. I think if you were in an ancient forest, say a hundred million years ago, and you kind of squinted and looked around at the insects, you would recognize a lot of the forms, you know, they wouldn’t look too dissimilar to insects that you’ve seen today. But they might just not be the same species that we’re seeing today.
Victoria:
(Did these insects survive the giant asteroid that wiped out dinosaurs?)
This is a good follow-up to that, speaking of different groups of insects and what we see today. This question is, did these insects survive the giant asteroid that wiped out the dinosaurs?
Dr. Maccracken:
Well, some did. So insects made it through the Cretaceous-Paleogene mass extinction event, because we saw insects in the fossil record right before and right after that asteroid impact. And obviously we see insects today. So, some groups of insects made it through.
Now, there were a lot of extinctions among different species of insects, and that’s going to be really hard to figure out with just the body record, the body fossil record of insects. But what we know from the traces of their feeding on plants, remember those holes and the punctures that insects make in plants when they’re eating them, we can actually use those to tell us what sorts of insects survive that mass extinction.
And so, my PhD advisor and colleagues did this great study looking at insect damage before and immediately after the asteroid impact. And what they found was that if you’re an insect and you’re incredibly specialized on what type of plant you eat, so let’s say you only eat one species of plant, or maybe a few species of closely related plants, that made you more likely to go extinct. Because of the thing that you eat gets killed off by the asteroid, the mass extinction event, then you might also go extinct. It’s sort of like if you only eat Cheetos and that’s all you’ll eat and you can’t and won’t lead to anything else. And asteroid like destroys the Cheetos factory, then you might die. If you have to, if you can’t switch to another food source, say cheese-Its, then you’ll die. Maybe you do switch to a new food source and you survive. And so in general, what we found was the more specialized your diet, the likelier you were as an insect to go extinct during that extinction event.
Victoria:
Oh, man. I should probably eat something besides Cheetos then.
Dr. Maccracken:
Yeah. Yeah. For many reasons, probably.
Victoria:
Not enough nutrients in Cheetos.
Dr. Maccracken:
I don’t think so. No.
Victoria:
(Did the insects have bones? Teeth?)
All right. Let’s see. We’ve got some more questions coming up about insects of the past. This question is, did the insect have bones or teeth?
Dr. Maccracken:
That is a very good question. No. Insects don’t have bones, nor do they have teeth, they have what we call an exoskeleton. And so that’s that kind of hard kind of shiny layer that you see on the outside of insects. You know, think about how a beetle has kind of hard parts covering his whole body, that’s their exoskeleton. And they use that for protection and also to support themselves and for all of their muscle attachments, and all of their, you know, organ systems. Whereas humans and other mammals and other vertebrates have skeleton on the inside, that helps us, you know, stand up and it supports us and, and we attach all of our muscles to it and allows us to move. So they just do it in a different way. And, you know, it’s very successful for insects.
And they also don’t have teeth. Their mouths are pretty interesting. There are a bunch of different I guess styles of insect mouths. Things like grasshoppers or beetles, they have what we call the mandibles, the chewing mandibles. And so it’s sort of like big claws that help them manipulate the food, and they can use, you know, different limbs to move food into their mouths. We also have things like the mosquitoes that have more of a siphoning mouth part, think about butterflies and how their mouths can curl and uncurl and suck up the nectar of flowers. And so they’ve taken this, you know, mouth part morphology, the mouth part structure, and they’ve been able to evolve different styles for different food sources. And it’s really helped insects become as diverse and as abundant as they are today.
In fact, insects are the most diverse macroorganism or large organism on earth, far, far, far outnumbering the diversity of all the invertebrates and all the plants. Insects are really it when you want to look at a diverse group of organisms.
Victoria:
Wow. That is incredible. I always think about that. Like whenever I see a bug that I don’t know what type of bug it is, I always like take a picture. I’m like, what is this? And then I start Googling, and I find that it’s something I’ve never even heard of. It’s really cool.
Dr. Maccracken:
Yeah. Yeah. It’s, I mean, it’s fun that, you know, even amateurs living in, you know, neighborhoods in Denver or neighborhoods anywhere in the world. You can start to learn your native fauna, your native insect fauna. And often times, if you really know your insects, you might be able to name a new species. There’s just so many insects to be discovered, that it’s, you know, if that’s what you’re passionate about, it’s definitely one of more fruitful sciences. Today there are almost a million types of insects that have been described, but we think they’re up to 30 million or more insect species on earth today. So, you know, you could run out to the desert or, you know, run down to the tropics and just start naming species, if that was really your passion.
Victoria:
(Where did they live?)
Wow. That is awesome. Yeah. So, if any of the listeners want to name insect species, sounds like there are many opportunities to do so.
Okay. This next question. You’ve touched on this a little bit, but if there’s anything else you want to add or elaborate. This question is where did they live?
Dr. Maccracken:
Well, insects lived everywhere, everywhere on Earth.
In fact, today you don’t really find insects in Antarctica, but in the past, they were certainly there. There were jungles covering Antarctica when the Earth was warmer than it is today. And so there’s lots of evidence of insects in those fossil deposits, whether it’s their bodies or the damage that they’ve left on things like fossil leaves.
And, you know, insects today, you find them in some of the most Northern latitudes and obviously down into the tropics where they are super diverse and abundant. And so this was probably the same as in the past, as in deep time.
Insects were likely the most diverse and abundant animals in ancient ecosystems like they are today. And so. Where did they live? They lived everywhere. They lived, you know, from the sky they’re flying around all the way buried into the ground and everywhere in between. Just like today, especially I it’s kind of cold where I am right now. But when it’s a little bit warmer here, you just, if you’re looking for insects, you find them everywhere. And I think that’s what it would be like in the past as well.
Victoria:
That’s very cool. Yeah. It’s a little cold here too. So sometimes on cold days I find more insects in my house than I expect to.
Dr. Maccracken:
Yeah. Yeah, exactly. I do remember though. I was up in Winter Park a few years ago, Winter Park Colorado. And I saw this type of insect on just like walking around on a lodgepole pine and there was about three feet of snow on the ground. And I was like, how in the world is this thing out and about right now? But it’s actually evolved to not let its, you know, essentially blood freeze. And so, even in cold environments, sometimes insects can be out and about. So, you know, keep an eye open. You will, you know, outside of your home, even, you know, you can find insects pretty much all the time if you’re really looking for them.
Victoria:
(What did insects eat? What did the insects eat besides plants? Did they eat dead animals?)
That is incredible. Ooh. Maybe, maybe next time I’m going for a walk when it’s snowy or I’m up in the mountains and it’s snowy. I’ll definitely keep an eye out. That’s amazing.
Alright. And this next question, you’ve already answered it in part, but again, if there’s any more details that you want to add. What did insects eat? What did the insects eat besides plants? And did they eat dead animals?
Dr. Maccracken:
They absolutely ate dead animals. Insects are very important in the decomposition of dead animals and dead plants and, you know, whatever dead material is kind of rotting. And so you get things like carrion flies, flies that lay their eggs into a deceased animal, and the eggs hatch, and you get the fly larva. And so, you know, we found things like botflies in the fossil record. So we know that there are lots of flies around that are probably living off of decaying material.
What else did they eat? Well, we know that there were things like mosquitoes and biting midges that fed on the blood of ancient animals. And then there are the predators, like we were talking about, things that are eating other insects.
And so insects fill, you know, a huge range of ecosystem services. And, and we know that they were doing that in the past as well.
Victoria:
(Did the insects eat more plants than now?)
Super cool. Speaking of insects eating, this question is, did the insects eat more plants in the past than now?
Dr. Maccracken:
Wow. That is a really insightful question. So the long and short answer was, yes, it depends. So it depends on what time period you’re looking at.
One thing that I do with my data collection is I measure how intensely insects are eating plants. And that gives us an idea of, you know, how much of a forest might be consumed by ancient insects. And what we found is that the amount that insects eat is a direct result of essentially the climate, the temperature. And that’s related to the amount of carbon dioxide in the air, because the more carbon dioxide you have in the global atmosphere, the higher the temperature of the earth is. And what we found, and this might be getting a little too into the details of this, but insects are eating plants for nutrition. And one of the elements that they need is nitrogen. And so, there’s this ratio between carbon and nitrogen, and that ratio changes when you have more carbon dioxide in the atmosphere, it actually decreases the nitrogen in the plant. So essentially when you have more carbon dioxide in the atmosphere, the plants are a little bit less nutritious, so insects have to eat a little bit more. And so what we find is that when the atmosphere at carbon dioxide goes up, the intensity of herbivory also goes up.
And this is really important for us today because we are changing the climate. We, as humans, are changing the climate; we are introducing a lot of carbon dioxide into the atmosphere. And why should we care about, you know, insect herbivores in the past? Well, we have to worry about them potentially eating more. And one insect eating a little bit more isn’t a big deal, but think about our entire agricultural system, you know, we spend billions of dollars each year trying to stop insect pests from eating the food that we’re growing. And so, you know, this is something that we have to understand better about the past, so that we can prepare ourselves for the future. And also, you know, so that we can try to mitigate our release of carbon dioxide so that we, you know, we take better care of the earth and, and we, also in turn, take better care of ourselves, and make sure that we don’t have to spray as many pesticides or have to cut down as much forest to expand our crop lands. And so it’s, it’s really interesting how carbon dioxide can, you know, can change the insect plant relationships so much.
Victoria:
(What did those insects do back then, besides eat?)
Wow. That is incredible. I never thought about that aspect of climate change in insects before. That’s, that’s crazy.
Okay. Let’s see. this next question is a good follow-up to that. What did those insects do back then, besides eat?
Dr. Maccracken:
Well, they likely were interested in mating. And so they’re making displays with their bodies or making different noises and trying to attract, you know, a mate to produce, you know, little insect babies.
And then they’re probably flying around, they’re probably, you know, sleeping at night. But when you’re eating something like plants, you gotta spend a lot of your day eating. So, you know, they’re probably not doing, you know, terribly interesting things or I guess to, you know, a general person. They’re probably not doing very interesting things other than eating and mating, and just taking care of, you know, making sure they have enough water, and things like that.
Victoria:
(Did any insects live in the water?)
That segues well into this next question. Speaking of water, did any insects of the past live in water?
Dr. Maccracken:
Yes. Yes. There are fossils of insects that we know today live in water and based on their anatomy, based on their structures, for instance like in their legs, that we predicted they lived on the surface of the water or actually in the water, like diving beetles.
And we also know that insects are basically crustaceans, the group of organisms that live in the oceans, things like crabs and lobsters and all that kind of stuff. And so they’re just one lineage from the crustaceans. And so, you know, I guess their relatives and their ancestors were actually from the oceans.
Victoria:
(I want to know how annoying they were to dinosaurs. Did some insects benefit the dinosaurs somehow? Did insects help dinosaurs at all?)
That is super cool.
All right, the next three questions are all about the relationship between insects and dinosaurs. So this first question, the question asker says, I want to know how annoying they were to dinosaurs. Did some insects benefit the dinosaurs somehow? Did insects help dinosaurs at all?
Dr. Maccracken:
Hmm, that’s a great series of questions. So I don’t know how annoying they were to dinosaurs. They definitely fed on dinosaurs, things like biting midges. But I can’t tell you if the dinosaurs really felt them or did preventative measures. For instance, if you think about things like elephants today, you know, they might roll around in mud, not just for sun protection, but for insect protection. So we don’t know if dinosaurs might’ve done something similar to, you know, ward off biting insects. But I can imagine that they might be fairly annoying, you know, especially if insects are getting around your eyeballs or something like that as a dinosaur, I would, I would be very annoyed.
And then did insects have any mutualism with dinosaurs? Did they help dinosaurs at all? Well, I, you know, ecology is really, it’s just so much beyond the scope of what humans can understand. It is very intricate. So I would say probably there are some mutualisms between dinosaurs and insects, some cases where dinosaurs and insects both benefited from each other. But I can’t think of any off the top of my head.
What I can say about insects is that they support kind of the lower levels of land-based ecosystems. So they’re eating plants, keeping forests maintained. You know, if you’re in a forest, you know, you see lots of different kinds of plants because insects are specialized on different plants and they’re eating constantly. And so, you know, you don’t just get one plant taking over an entire forest, insects help maintain the diversity of plants and keep the earth from becoming, you know, overwhelmingly green. They just help regulate plants on earth. And so, you know, they help the ecosystems that these bigger carnivorous dinosaurs are living in, these bigger herbivorous dinosaurs are living in.
And they also are the food source for a lot of things. And so maybe if you have T-Rex, it’s not interacting as much with insects, but it might be, you know, sometimes eating the things that eat insects or, you know, eating things that ate plants and the plants were in turn, you know, in part related by insects.
And so, you know, insects are this kind of corner stone, this really important puzzle piece in a lot of ecosystems. And so even if, you know, there aren’t these direct relationships between dinosaurs and insects, you know, if you took away the insects, then the ecosystems would collapse and it would be hard for anything to live.
So just like today, you know, you’ve got to love the insects because so much of the life that we depend on on Earth is in some way tied to insects.
Victoria:
(Could bugs kill big dinosaurs like a T-Rex?)
Wow, that first part of the question about them being annoying to dinosaurs, it gives me a mental image. You know how cows flick their tails back and forth when there’s flies that are flying near their butts. It kinda just gives me an image of dinosaurs tuning their tails as flies go by.
Here’s another dinosaurs insects question. Could bugs kill big dinosaurs, like a T-Rex?
Dr. Maccracken:
Hmm, that’s an interesting question. I’m not sure. I don’t know the answer to that. I would imagine that no, insects probably won’t be killing dinosaurs. A lot of insects might be parasites. They might harm dinosaurs, but hopefully not kill them, because if you’re a parasite and you rely on dinosaurs for a food source, you don’t want to be killing off your food source.
Victoria:
(Did any dinosaurs eat the insects?)
Yeah. That makes sense.
And this is our last dinosaur question. Did any dinosaurs eat the insects?
Dr. Maccracken:
Yeah, dinosaurs definitely ate insects, starting with the herbivorous dinosaurs, which, you know, they’re so large and they’re eating such big quantities of plant material that they’re definitely consuming insects all over the place, but they’re not targeting that, they’re just sort of an oops in their diet. But yes, herbivorous dinosaurs are eating insects on accident.
And then probably some of the smaller, more like bird-like dinosaurs, were eating insects. They were, you know, some of them were likely insectivores, eating insects , or at least, you know, some dinosaurs might’ve been insectivores, or insect eaters , at some point in their life, maybe when they were smaller and then they graduated to larger and larger prey.
So, yeah. Yeah. I think some dinosaurs did eat insects at different stages and for different reasons, or accidentally,
Victoria:
(Would they eat us?)
One time I was riding a bike and I accidentally ate a bug. So I guess I’m like a dinosaur too.
Okay. Speaking of insects eating things, or dinosaurs eating things, this question is, would insects eat us?
Dr. Maccracken:
Well, they’ll definitely take bites out of us or suck our blood. And that probably would have happened in the past as well. And, you know, this is a little bit creepy, but you know, if we were to die in an ancient ecosystem, they would eat our remains and we would get cycled back into the ecosystem, and our nutrients would live on forever.
Victoria:
That’s awesome. I’d like my nutrients to live on and be part of the ecosystem.
Dr. Maccracken:
Yeah, I would too.
Victoria:
(What insect was the scariest?)
So we’re down to our last three questions. This question is what insect was the scariest?
Dr. Maccracken:
Hmm. What insect was the scariest? Well, I don’t really see any of the insects as being particularly scary. I guess, since I study them, I just think that they’re all very, very cool. But I think if I were back in the Carboniferous and, you know, being potentially dive bombed by those giant dragonfly-like insects, that might be pretty startling, for sure.
Victoria:
Yeah. I was thinking about that earlier with the question about what is insects sound like. And I was trying to imagine that sound of the dragonfly wings and magnifying that by a lot. I expect that they would be pretty loud too.
Dr. Maccracken:
Oh yeah, for sure. And based on how modern dragonflies are so agile, you know, they can, they can, you know, essentially go forward and backward and they can seem to hover. And they’re just really quick predators. And I would imagine that seeing something that’s two or three feet in diameter that is so agile and quick, would be startling. Yeah, I agree.
Victoria:
(Were they gross?)
And this next question, bit of an opinion question. Were they gross?
Dr. Maccracken:
Were they gross? No, no. I don’t think insects are particularly gross. I think they’re very, very interesting. And I think that the more you study them, the more you come to appreciate them, and you can kind of see the beauty and things that a lot of people might consider to be speak gross or scary.
Victoria:
(How did you know you wanted to study fossil insects?)
Yeah. That makes sense.
And this is our very last question. This is a question about you. How did you know you wanted to study fossil insects?
Dr. Maccracken:
Wow. That’s a really nice question. How did I know I wanted to study insects? Well, I didn’t always want to study insects. But when I was a little kid, like really little toddling around in diapers, I remember picking up rocks and looking under them to find all of the insects and other, you know, bugs that live under rocks and in decaying wood. And so it’s always kind of been a fascination with me. But for a long time, I thought I might want to study vertebrates or things with backbones, because you know, they’re so charismatic. I mean, you got to love things like gorillas and pandas and, you know, thinking into the fossil record, dinosaurs are amazing. And so are, you know, wooly mammoth, and there’s just, there’s so many really cool creatures.
But my main love was ecology. It was looking at nature as a whole and seeing how things interacted. And so over time, I started getting more interested in plants, but I realized I didn’t want to be just a straight paleobotanist. It didn’t feel right. My gut was telling me I needed to do something else.
And that’s when, you know, I, I took a class in college on entomology, and I fell in love with learning about the insects. There’s just so much going on with them, and they’re so diverse and they’re so beautiful. And they’re just infinitely amazing. But they just will always amaze you with the more you learn about them.
And so I remember reading a paper by my PhD advisor at the time I was working after college. And, you know, he was talking about insect damage on fossil leaves and kind of opening up this whole snapshot of ecology that you wouldn’t have ever been able to see just from the body fossils, just from the fossils of insect bodies. And at that moment, I fell in love with it, and I’ve been doing it ever since.
So it was really a progression of being interested in a million different things and then kind of following my passions to where they lead.
Victoria:
That’s an incredible story.
Dr. Maccracken:
Thank you.
Victoria:
That is all of our questions, but do you have any questions of your own for the listeners?
Dr. Maccracken:
Oh, that’s great. So, I have a question and a piece of advice.
So my question is what was the last insect you saw? And I guess spinning off of that, what do you think it was doing? Was it a predator? Was it an herbivore? Did he eat plants? Just think about what it might’ve been doing in that moment.
And then as far as looking at, or thinking about what I study, and then trying to detect it in your daily lives, the next time you go outside and you’re walking around the neighborhood and maybe you see leaves on the ground, or still in the trees, if it’s warmer, just look at the leaves or the bark, look for signs that an insect has been there. And when you start noticing it, you find that it’s everywhere, and you’ll start noticing it more and more and more, and you’ll see all these different great patterns of insect herbivory.
Victoria:
And if the listeners want to get in touch with you, do you have a website or a professional social media page that you would want to direct them to?
Dr. Maccracken:
Sure. I am on Twitter. My handle is @Gussie_Mac, that’s at G U S S I E underscore M A C.
Victoria:
Well, be sure to check out Gussie @Gussie_Mac and send in the answer to your questions.
Awesome. Well, thank you so much for doing this interview today. I really enjoyed talking to you. I learned so much about insects. I thought I knew a lot about insects, but turns out I didn’t. So thank you so much.
Dr. Maccracken:
Oh my gosh. Thank you for having me on your podcast. I’ve really had a wonderful time.
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