Chris Burwell of Queensland Museum

Ants: bioindicators of climate change

Because some of them bite, sting or pass on life-threatening diseases, lurk in our kitchens at night, or eat our garden plants, not to mention occasionally decimate our food crops, insects tend to get a bad rap. But that’s not really fair. If they didn’t exist, nor would we. In fact, because of our existence, theirs is under threat. And perhaps this AMAZINGLY diverse class of creatures can show us the impact we are having on the planet. There are scientists out there trying to do just that – and they could use a little help from you.

One of those scientists is Queensland Museum’s Dr Chris Burwell, Senior Curator of Insects. He’s got an encyclopedic knowledge of insects that he’s going to share with you!

Meet our guest

Chris Burwell joined the Queensland Museum in 1995 and is now Senior Curator of Insects. Chris received his entomological training at the University of Queensland where he graduated with an Honours degree and was awarded the prestigious University medal in 1988 and a PhD in 1995.

Chris’ research interests focus on the taxonomy, biology and ecology of Hymenoptera, which includes bees, wasps and ants. He specialises in ants and minute parasitic wasps (Chalcidoidea).

Current research projects include investigating the potential of ants as bio-indicators of climate change in the subtropical rainforest of Lamington National Park (as part of the IBISCA Queensland project). In collaboration with the Queensland Parks and Wildlife service, Chris and Dr Aki Nakamura are assessing the impacts of invasive ants on the insects and spiders of coral cays in the southern Great Barrier Reef.

Chris has an ongoing research interest in the diet of insectivorous vertebrates and the co-evolution of insects and their predators. This work is mostly carried out in collaboration with Dr Chris Pavey from the Northern Territory Government. Recent work on this topic has focussed on the diet of endangered central Australian mammals including the Southern marsupial-mole, Brush-tailed mulgara, and Kowari.

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Kylie Hay: Thanks for joining us on the Museum Revealed podcast, this episode was recorded using Skype, so you may hear a bit of background noise, which we like to call atmosphere. We hope you enjoy this episode, too. So let’s get started.

LC: Because some of them bite, sting or pass on life threatening diseases, lurk in our kitchens at night or eat our garden plants, not to mention occasionally decimate our food crops. Insects tend to get a bad rap, but that’s not really fair. If they didn’t exist, nor would we. In fact, because of our existence theirs under threat. And perhaps this amazingly diverse class of creatures can show us the impact we’re having on the planet. There are scientists out there trying to do just that, and they could use a little help from you. One of those scientists is Queensland Museum’s Dr Chris Burwell (CB), Senior Curator of Insects. He’s got an encyclopaedic knowledge of insects that he’s going to share. With me today, Laura Cantrell (LC), museum graphic designer and sometimes podcast host and you. Hi, Chris.

CB: Hi, Laura.

LC: At any time, it’s estimated that there are some 10 quintillion individual insects alive. That’s an incredible statistic. Is it true?

CB: Yeah, look, that’s a hard thing to answer because I don’t even know what a quintillion is, but I’m assuming that it is, a lot. I guess that’s the main thrust of that statistic, is to get across the sheer vastness of numbers of insects and other sorts of arthropods that are out there that we just have no awareness of. So it might be right. I’m sure that it’s a process where they’ve tried to multiply up through the numbers. But, yeah, it’s probably something in that order. But, you know, who knows? I mean, we’ve got between three and four million insect specimens in the collection of the Queensland Museum, and we haven’t even counted those. There’s a classic quote by a famous ant person researcher called E.O. Wilson, that invertebrates and they’re mostly insects are the little things that run the world. And that’s that that sheer numbers gives you an idea of how that’s exactly the case.

LC: Well, of all the insect species, you’ve got a particular interest in ants. What makes ants so fascinating to you?

CB: A couple of things. I mean, I did my PhD on very tiny, minute parasitic wasps that attack other insects. And so it’s a little it’s a fairly easy stepping stone to work on ants because ants are also in the same group of insects that include bees and wasps. And I think I kind of got into ants gradually. And one of the reasons I got into them is because everybody knows what an ant is. So, you know, you can have meaningful conversations with with other people, you know, members of the public about ants because everybody knows what they are and everybody’s got a story about them. But lots of other reasons. I mean, one is a bit like those numbers that numbers that you quoted before, there are literally thousands of different species of ants. The other really cool thing about them is that they live in colonies, truly social colonies, you know, big nests where there’s a queen that does the egg laying and there are workers which are all females that maintain the colony and have little larvae. So that’s kind of interesting in itself. And I mean, everybody’s got a bit of a simplified idea of what an ant colony is like, but ants to all sorts of weird things. I’m just about to give a lecture to some students on ants, and I’ve been looking up some of the weird colony structures that they have. There are some which actually make their living by moving into the nest of a different ant species, usually quite related, and they co-opt the workers of that nest to rear their own larvae and they make them slaves, basically their own larvae, and then they turn into a little worker. Ants don’t do anything to help maintain the colony or feed the larvae or anything like that. They actually find colonies of the one that they parasitise and capture the capture the pupae and bring them back home and make them slaves to do all the work for them, which is just remarkable.

LC: Yeah. So if we see an ant crawling around our kitchen, it’s going to be female then?

CB: Yeah, absolutely. Yeah. So all the workers things that most people would think were an ant are all female, which is a kind of a weird lifestyle in itself. So ant colonies, when they reproduce, they produce winged stages which include females that might go off and become a new queen, and then they make the males, which look quite different to the females and they release them all after the weather conditions are right, usually after a bit of rain and the females from one colony will mate with males from another colony, they don’t mate members of their own colony and then the males just basically die. They’re very short lived and they’re basically just there for a reproductive purpose. And then the females go off and hopefully found a new colony.

LC: Well, you’ve been investigating the potential of ants as bio indicators of climate change. Can you give us some insight into that?

CB: So this is some work that we did a few years ago now, and it was looking at the idea of trying to look at the way that ants and other groups of insects change as you go up from the lowlands where it’s warmer, up mountains, rainforested mountains. And as the higher you go, the climate on the mountain changes, it becomes wetter and it becomes cooler. That’s the most significant part. And because there is that changing climate, as you as you climb up the mountain and, you know, if you’re in south east Queensland, for instance, and it’s boiling hot down in the in the lowlands, what do you do? You go up to the top of mountains at Mt Glorious or somewhere like Lamington National Park where it’s much nicer and cooler, and the insects respond to those changes, too. So as you go up the mountain, the sorts of species of ants down the bottom gradually change, the higher up you go. And so the idea of that that as indicators of climate change is that if we can work out where particular species are living now and what range of elevation they might be living up, we can then go back again and again and resurvey those ants and track to see if they’re changing their distribution. So as the planet warms up due to climate change, animals have got a couple of things they can do to maybe track the preferred climate that they like. They could either shift southwards in this hemisphere, at least because if you go further south, it gets cooler. And the other option is as it warms up, you could climb higher up in the mountains. So presumably as things warm up, we might see shifts in where ants are living on mountains and they’re tending to live higher up than they have been in the past.

LC: Is there any way that we as citizen scientists can help with projects like this?

CB: Yeah, there is. I mean, often we for that particular project, we had enormous numbers of scientists that were coming in and answering that same sort of question on their own, various groups, plants and moths and things. And we had lots of volunteers that came along to help out with the field work because those sorts of studies require a lot of lugging equipment around and sorting samples and things like that. So. So just engaging with those sorts of projects and and volunteering is one sort of thing. Ants – it’s a bit tricky. But there’s lots of other groups of insects. I’m interested in dragonflies and damselflies, where it’s really easy to identify them from photographs. So not really easy, but it’s it’s easier than other groups. And there’s lots of citizen science websites where people can take a photo of something and log exactly where they took that photo. And online experts and a community of people that are interested in those particular insects will offer up identifications. And then if enough people agree that it is that particular species, then that goes up to various global or national portals where that information is used for scientific research or can be used for scientific research.

LC: Well, speaking of keeping an eye on insect activity, especially around our homes, I found a cicada the other day. Can you shed some light on that process?

CB: Yeah. So insects are arthropods and it’s an enormous group of animals that have an exoskeleton. So unlike us, you have we’re soft and squishy on the outside and we’ve got our skeletal elements that gives us support and enable us to move this internal whereas insects that kind of inside out inside to the soft and squishy bits. And they have this basically a suit of armour on the outside that’s broken into a series of plates so that they can move around. But that jacket, that suit of armour restricts how they grow because it’s not it’s not very elastic. It can’t just expand as the animal gets bigger and bigger. And what they need to do is once it’s reached its capacity, it can only expand as much as it can. They have to shed that cuticle and the sluff it off and then step out with a nice new soft one that will harden up over the next few hours. And it’s it’s a very complicated process because it’s quite a big chemical investment to have a suit of armour. So they often suck back quite a lot of the chemicals. And what they shed is actually quite thin compared to what it would be like when they were alive. But it’s even more complicated because it’s not just the outer coating and all of the hairs and spines and things that get shed, the actual front part of their digestive system thier fore gut and the back part of their digestive system is lined with exoskeleton, the cuticle. And insects have this amazing, they don’t breathe through their mouth. They don’t have lungs like us. They have a whole system of kind of like air conditioning ducts that run all through the body and and go smaller and smaller and supply the individual tissues with oxygen. And the majority of that internal air conditioning duct system is lined with cuticle or exoskeleton as well. And that has to be shed every time they get a new suit of armour. So it’s it’s a remarkable process.

LC: Yeah, it really is. Now on behalf of anyone with a kitchen, I’ve got to ask cockroaches, are they as dirty as we think?

CB: Yeah, they can be, potentially quite dirty sorts of animals. I mean, I think if they’re living entirely inside your house, they’re probably not going to be so bad. But the problem with a lot of cockroaches that like to live with people, we have a number of species that come inside our homes, they often like to go to unsavoury places as well, like sewers and things like that. They transmit diseases mechanically. They just get bacteria and things on the outside of the body. So, you know, if they were feeding at a bit of dog dropping outside or walking through a sewer and then they come in and walk over your food, that’s how they might transmit diseases. But that’s the nasty indoor ones. In fact, there are lots of native cockroaches more than you have inside your house that live outside in the environment. And they’re perfectly clean and they don’t come and feed on your food inside. So are no problems at all. And they’re actually quite an important part of the ecosystem.

LC: Well, you also have an interest in dragonflies. What is it about them that you find interesting?

CB: Dragonflies and damselflies. There’s two kinds of sorts of dragonflies that the bigger the more robust ones and the damselflies are more delicate. I like them because they’re I mean, I’m a bird watcher, a birder as well. And they’re basically the insect equivalent of birds that are they often really brightly coloured, they do kind of cool things in the environment. They occupy water bodies because that’s where the immature stages live. They’re aquatic underneath the water and the males are often bright coloured and maintain territories and defend them against other males. And I’ve really gotten into photography now. So they’re great things to run around and take photographs of. They’re really cool insects.

LC: What’s it like to describe a species?

CB: That’s pretty cool? I mean, that’s one of the cool things about working at the museum is discovering new insects and describing them. And it’s actually easier than you might think. There’s probably only a third or maybe even less of Australia’s insects actually have been described, which means that been given a proper scientific name. So it’s actually not that hard to go out and find new ones, but it’s the process of it that is the hard part. The hardest part is deciding if it is new. You’ve got to work out whether this thing is different from the species that have already been described. And then you have to look at how it’s different. You write a formal description. So it’s actually quite a convoluted process. But that whole excitement of finding something new is actually amazing. In some groups like butterflies, which there’s been lots of people doing butterfly work, lots of amateur entomologists that contribute to that, and also dragonflies. We’ve described most of the species. But if you find a new one of those, that’s even more exciting because, you know, most of them have already got names. So it’s almost like if you do find it, you’re one of those.

LC: Well, this next question might be a little bit difficult, but what would a world be like without insects?

CB: Yeah, look, it’s it’s a really difficult question to answer. I suspect there’d be some sort of collapse of the ecology of the world if they just completely disappeared. I mean, if you took that amazing first number that you talked about and wipe them out instantaneously, a whole lot of sort of ecological processes would just sort of fall over. So insects and other arthropods play major roles in nutrient recycling. So there’s insects that break down dead animals, there’s insects that break down wood, you know when a tree falls in the forest, does it make a noise? Yes. And then also the insects move in to break it down and return those nutrients to the soil. They’re really important in pollination. Lots of plants rely on insects to pollinate them so they can set seed and produce more plants. And lots of our food crops are required, require insects to pollinate them. So it wouldn’t just be a collapse of natural ecosystems, but human beings would struggle with the implications of insects suddenly disappearing from the well.

LC: Moving on to a slightly macabre question, how does insect spray kill insects?

CB: Oh, I’m not sure if I’ve got a good answer for that. I’m not a biochemist. I have to go away and have a look at it. I imagine that there will be some sort of active chemical in an active ingredient in those sprays that basically disrupt the biochemical activities of the insect. That’s one particular way. I mean, alternatively, it just could be a toxin that basically destroys them. But there’s there are other sorts of actions that can be used to destroy them. In the old days, I think people used to put down some sort of powder or dust. And what that does is that if it gets inside those breathing tubes that go through the tissues of the insect, it basically scrapes the lining so that they lose lots of water. So that’s one thing about insects is that they’re good colonisers of land, and because they’ve got this cuticle, they’re desiccation resistant, they don’t dry out. So if you can find something that scratches the surface of their cuticle and the little lipids on the outside, that stops that desiccation, you can kill them that way. So, yeah, I think different sorts of chemicals and different sorts of ways of killing things have different sets of actions.

LC: Well, we’re going to wrap up now with our Rapid Fire Museum in a Minute Questions. Are you ready, Chris?

CB: I am, I think.

LC: OK, here we go. Favourite museum object?

CB: These amazing male, tusked, all the flies insect collection.

LC: What did you want to be when you grew up?

CB: A biologist of some description,

LC: Favourite museum memory?

CB: Working on a Pliosaur fossil when I was doing work experience in the museum in grade ten.

LC: Which is more iconic – Muttaburrasaurus or Mephisto?

CB: I think Mephisto.

LC: Favourite thing about your career?

CB: Being in the field.

LC: Oh, well, now I know the answer to the next question. Would you prefer to work in the field or in the office?

CB: Absolutely. In the field

LC: Indiana Jones or Jurassic Park?

CB: Indiana Jones.

LC: If you could do another job in a museum for a day, what would it be?

CB: I’d like to try out taxidermy.

LC: What do people think you do at work?

CB: They don’t think I do research. They think I’m on the floor talking to the public.

LC: Oh, that’s great. Thank you, Chris.

CB: You’re welcome.

LC: If you’re interested in becoming a citizen scientist and helping, experts like Chris we’ll add some links to the show notes. Insects are truly amazing. Maybe now you’ll find yourself reaching for the insect spray a little less often. Thanks for joining us on the Museum Revealed podcast. Interested in uncovering more stories? Click the follow button to be notified of the latest podcast episodes. You can follow Queensland Museum on social media @qldmuseum or head to our website and while you’re there, sign up to our e-news list to be the first to know what’s on at our museums. Until next time. Stay curious.

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