 Tonight we're visiting a world of insects. Insects are enormously important, you know real are something like possibly as much as 90% or even more of the animal species that we have. They occupy many different habitats, largely but not exclusively terrestrial, and they're spread all across the globe. Insects are undergoing a catastrophic decline and I expect Erica is going to mention that to us. And since they are at the heart of many of our planetary ecosystems, this is a considerable concern. However, although we know quite a lot about some insects, there are some that we know less about, one of which is the flies, the diptera. To many of the audience, flies might mean something, mages, blue bottles, house flies, but actually this is an enormously diverse group of organisms. We're very fortunate tonight to have with us an international expert on this group, Dr. Erica McAlister. Erica is a well-known scientist, she's a senior curator at the Natural History Museum in London. She's an honorary fellow of the Royal Integral Society. But more importantly for us this evening, she's passionate about flies, and so she's going to speak to us this evening about the changing chain of flies. So thank you very much, Erica. Thank you. Can you hear me? Yeah, I've got a loud voice at the best time. So I, and I would get excited, so sorry. So thank you for that introduction, it's lovely. I like being an international scientist. So, yes, I'm very, very lucky. I'm going to talk to you tonight about some of the things that slightly obsessed me. I won't necessarily be going into all the ecology about flies, but I want to talk about certain things about them to help explain their actions. So, okay. So I'm very lucky. I work in the Natural History Museum in London. Now I know you've got a lovely museum here and have to careful because there's a retired person in the audience who worked at that museum, and I say it's lovely, but I am biased and we do have the best. Sorry. And I think globally we have one of the best museums because when you come to the museum when you walk into the galleries, all you're seeing is 1% of our collection. Behind the scenes, along with a load of wise and old scientists like myself, there's 80 million specimens. So we have what is described as a temple to natural history. We hold the biological heritage, along with all the other museums and all the other collections in the world to help us understand the past, and also nowadays more importantly, to understand the future. So we can go into these collections, we can mine them, we can understand all sorts of things when it comes to climate change, biodiversity, tax on me, etc. Now I'm very biased because I work with the best animals on the planet. Obviously I work with the flies. Now I know that some of you may not feel exactly the same as I do, but trust me, once you've started looking at flies, no other animal plant, bacteria, fungi comes quite close to it. And I'm really lucky I managed to go around the globe to very exciting places. Yes, this is me hoovering a pig in Hounds Low City Farm, wasn't so glamorous. But there is yes taking photos of feces. As a fly specialist my mother is very embarrassed about certain of my habitats but I will hang around feces. But I am very interested in going around the world describing species. So if it wasn't for the pandemic I'd spend most of my time in the Caribbean. Thank you taxpayers. It's very nice. Obviously I have to describe species with rum it's very important. But I will bring them back and study them in the museum. And these specimens where we added towards this wealth that we have there already. Now I'm not the first person to describe insects. Nope, I'm not the first person to describe animals. We've been doing it for millennia. But it was only with Linnaeus that we actually started properly to organize how we did this. And Linnaeus is brilliant. You know he organized a lot of us. He did it in a language that we could all universally understand. And now universally don't understand. But it's something that was very important. But when he started describing flies. So here we got muskid domestica, the housefly that everyone knows. The description is really limited. Small black fly. That's about another 9,000 species you've just described. And he had no picture with it. We didn't know what earth we were looking at. It didn't really help us. So we needed more things. And the advent of the microscope pretty much at the same time really helped things kick into gear. I was given a talk at a boys school at the weekend. And they had one of the first editions of micrographia. And try as I might they wouldn't give it to me. It's like come on, surely I deserve it. Because Robert Hooke's micrographia, you must have all seen this. It's a fabulous book. And what was amazing is when he was looking down his tiny little microscope. And I've held one of these. They're absolutely my new little things. He was describing everything that was close to him. So he was describing some really quite revolting things in many ways. He did a lot of lice. He did some pubic lice. We don't want to know much about his personal habits. But he also because of he was looking close to him. He did a lot with flies. Now this is a really quite a fun example. But this is he describes a half life. So it's one of the earliest taxonomic failures I've come across. Because this is actually a horse fly. But what you can see here is he's really looking at the detail. He is looking at the individual eye facets on this head of this horse fly. So you can start to see that there's bands, there's patterns. And if you think about this, how old this book is, 250, 470 years old. And he's looking at the detail of this. It's amazing. You can look at the detail within the life cycle of the fly. And this is really important. They first started to really properly get to grips with describing these objects and how they look. And nowadays we have all sorts of technology to help us look. So this is you staring into the head of a blue bottle. Brilliant, isn't it? It's fabulous. Well, you may not think so, but I do. And this female is really quite important. And what is lucky for me is when we're describing it, all the features I want to describe, I can clearly see thanks to technology. So it's got me thinking properly. And my last book was about the shape of flies and why they are shaped. Because what flies have done is they've taken that blueprint. This is what you and most people think of as a fly. And they've just laughed in the face of it. OK, they like, no, you think that's a fly. I'll show you a fly. So before I get into that, I'm going to tell you what a fly is. And then I'm going to show you everything that a fly isn't. So here we go. This is quite a famous fly. Obviously these are crane flies, daddy long legs. And lots of myths associated with daddy long legs, because lots of people don't know which one is a daddy long legs. That's the problem with common names. So when we talk about flies and we think about common names, and we have a movie about a horse and a ghost, then there's a fly, either a real fly's flies, a may or flies, flies? No. When you're talking about true flies, if there's a house fly, there's a space between the words, it's a fly. Dragon fly, damsel flies made flies, one word. This is this is a fly從 insect, as I said. In fact, it's got three pairs of legs. If you know anything about crane flies, you'll know that's a bit of a joke because the slightest hint that their legs fall off. Our collection in the Natural History Museum is basically bodies and heads and whole drawers of legs. It is quite traumatic to see. You've got the three body segments, the head, thorax and abdomen. And yes, in most cases, flies stick to this. In most cases. Now, what makes a fly a fly? So as an adult, and we're just gonna talk about it, they have sartorial mouth parts. You have never been bitten by a fly. You've been sliced and mained and shredded and siphoned, but you have never been bitten because they can't do that. They have one pair of wings as adults, hence their name, diptera, dieterra, two wings. So unlike the hymenotra, the bees and wasps that have two pairs and the beetles that have two pairs, they only have one pair. And instead, they have the most amazing organs, the hawthairs, which act as their balancing organs. And these hawthairs are their proprioceptors. They're their gyroscopes. They enable them to be the best aerial flyers out. So they can loop the loop, they can yaw, they can roll, they can land upside down on the sea. When you're in your living room, flying around their lamp, have a look exactly how they fly, because it is quite amazing. Now, I saw those three things making a fly. There's lots of adults that don't have mouth parts, lots of flies that don't have wings, and even some flies that don't have water. They look like nothing as they should do. Yay! Here you go. Cute, isn't it? Well, never trust me when I say something cute because it's bound to be horrible. Just saying now. This is actually the backside of a larvae, a crane fly. So that very long length of larvae is quite cute. Now, the thing is about flies, they like a lot of insects go through a complete metamorphosis. So they go from a larval stage, egg stage sometimes, a larval stage sometimes, pupil stage and an adult stage. And this change in life cycle has enabled them to explore so many different habitats because they're separating out what the larvae and the adults eat. And the larvae are designed to eat. They really, if I'm coming back, I'm coming back as fly, because 90% of your life is just eating. It's fabulous. And to enable them to just concentrate on eating, they don't breathe with their mouths like us. If we tried to eat all the time, we would choke. So their bottom is what they breathe through. Yes, those little eyes, noop, little anal spiracles. Isn't that nice? Breathe in out of your bottom. It's an amazing adaptation. There's some really quite cute ones. Look at these. They look like little Tamagotchi, little cartoon characters, yep. So we go around identifying a lot of the immature flies by their bottoms. Again, it's a unique skill. I didn't think I'd have as an undergraduate, but they're quite cute. A lot of them look like army generals and things like this. But this is your common fly. Yes, maybe this is a fly. This is the head. Maybe it's a head that only some mothers will love, but it is quite amazing. So again, this is quite a higher fly. This is one of the blue bottles designed for scraping out dead and decomposing material. And the thing about a lot of the larvae is that they are designed perfectly for their habitat. They're like, they've got no legs. We call them precocious because they emerge earlier than a lot of the other insects. And so they are basically sleeping bags full of vegetable soup. So this is the amorphous little thing that can wiggle itself into all sorts of unique habitats. And some of them are not exactly pleasant. This is a common fly that you get in all your gardens. And you must thank this fly. Have you seen this fly? Does everyone know this little larvae? One nod of head. This is an amazing fly. It's a very, very common fly. And in fact, relatives that are still flying around at the moment, which is unusual. And see, this is the hoverfly. This larvae is the rack-tailed maggot, which some people now decided to call long-tailed larvae because rack-tailed maggot didn't sound as nice, but I'm going to keep it. And what these are good is these larvae are decomposers. So they eat all the dank decomposing vegetable matter. And in your garden, in the pond, the really dark dank edges, that's where they are. And because they have this enormously long annual spherical, they can get really deep into this anoxic environment. So they're great at nutrient recycling. So this is really important. If you go into your compost heap, my neighbors love me, she's doing again. She's through a compost, obviously. And I'm looking there to see whether we've got these. We're doing hoverfly legumes for all of these creatures now. Really important part of the environment. And then amazingly, they're adults, completely different, feed on completely different, really, really important pollinators. We're only just beginning to realize how important flies are for pollination. So this is one of the top, I think it's six pollinators in the UK. This group, they're really, really important. They're not as fun as some more I'm going to talk about in a minute, but they are just very good. This is another hoverfly. And this is one of the UPOIDs. It comes over, this is really cool because this is a migratory hoverfly. So this travels across Europe. We have just been using, my friend is in the Pyrenees right now, staring up into space, looking at all the hoverflies flying across the Pyrenees. They have worked out not me. They have worked out that up to four billion insects turn up in the UK each year. Most of them are hoverflies. And this is really important because this and the marmalade hoverfly do the exactly the same work as all the honeybees in the UK just to put that impact. Now, not only are the adults amazing pollinators, what they do because they're so high up, they're able to see relic populations of plants and so they're able to be really good at bucking the trend of species loss when it comes to genetics of plants. So they're able to cross pollinate as they go. Really, really important. And then their larvae, they don't feed on this decomposing material. No, the volatile warfare units, they eat aphids that aphidophagus and they can consume 400 aphids before they get to adulthood, which is great. They are just amazing things. They do look like bird feces. There's no getting around it, but if you see some walking bird feces in your garden, go find your aphids, put it on and it would be doing you an amazing thing. So they're really important when it comes to our agro-ecosystems in the UK. Now, so I've come in all shapes, as I said. I love them, here's some UK flies as well as some foreign flies. These two are in my garden. These are some of the hovels. This is Maradona clutches. This is the really noisy one when you're out there in the sun and you hear this thing, it's usually a little male of these going, hello ladies, because flies are basically a nanos. I won't swear, they're that close to flirting the entire time. They are designed to flirt. Everything about them. Look at this one. This is a dolly coated front legs of ribbons. It dances for the ladies. We've got this one here, which has basically got a whisk on its abdomen. So he was stroked the lady with his hairy genitalia. Isn't that attractive? And you have all these different things going on, but it's not only just for our poor flirting, there is different adaptations, these mouth parts for seedy. So when, and this one here with a bright red head, when this was described, they described it as bioluminescent and it was completely made up. It's the periods where no one checked anything. But yeah, I saw this fly and it did this. Didn't, did it? No, but no one's gonna check. Annoyingly. But it is one of the most dramatic flies and we don't know anything about it. It's in Africa. It's one of the largest species, most enigmatic found across the whole of Africa. Where's the larvae? So when we talk about the head, which I'm gonna do, as I'm gonna break this talk down to the head, the thorax and the abdomen. Because these are different parts concentrate different organs. And the head is where you have the vision. Now they all talk about flies being disgusting and dirty. Flies have to be some of the cleanest animals on the planet because they hang around dirty environments like your houses. Now your houses are filthy. I'm sorry, you're all filthy. And without saying anything untoward, you're all quite smelly. Now this is very important for flies and they will come in and they will use all their senses to find you and the food. So they have to keep themselves very clean. And one of the most important senses they had to keep clean is the eyes. Now, some of them have taken their eyes to extraordinary levels. These we've unimaginably called the big headed flies. Yep, these are papunculates and they have, you can see thousands of omatidium. Now dragon flies are the ones that we say have got these most omatidium. These are the photo unit, the individual cells on their head. So they have about 30,000. They have loads. Now flies saw dragon flies. I mean, I can't be bothered to do that. And instead, within each photo unit, where with the other insects, you've got a single fused ragdome where all the different photo cells are fused together with the color ones at the bottom, flies have split them. So flies now in each omatidium have six different angles where they can take an image. So when you try to swat a fly, which obviously none of you do ever, this is why they can just go, because they see you as a really slow, lumbering creature. It's like being in the matrix. They could just move out of the way because they're able to process this really, really quickly. In fact, with some of the work with the hover flies, they are looking at this to develop jump jet technology for super planes based on how they can move. Now, what I love in this one is usually the males have the largest omatidium at the front and these are called love spots. They really are, because he has to find the ladies. She is just interested in food. He is just interested in her. It's quite like humans really. But in this case, we've got very large omatidium on the females because she actually needs to find some very active, fast moving creatures within which to lay her larvae because she's a paratoid. Her larvae have to feed off grasshoppers and true bugs and things like that in order to develop. So she has to have the big eyes. But as I said, they use them for flirting. This is Akias Roschardia. It's an amazing, it's one of the stalk-eyed flies. Love stalk-eyed flies. What I love is this evolved independently 22 times in flies. It's like some flies got together and went, you've seen Jeremy, you've seen his omates. Can we get Bob to do that? Because they have this amazing, the sexual pressure in flies is enormous. And these will, they will rut like deer. Okay. And I was looking at some little ones in Ethiopia and to my PhD supervisor family and told me off, like, you're meant to be doing an adult work. And I was like, no, but look at the flies. And for two hours. And if they were the same size, that's when they would fight. And these ones, go away and look it up on YouTube. They would get on their back legs and they were probably 50 cuffs with their front legs. Really sweet. But obviously I'm an adult, but amazing. And if you look at the development of the optic nerve in the puparium, what's going on is it develops like a coil. And so the nerve will grow and grow and grow. Then immediately the adult hatches out of the puparium. It will engulf air and it will blow up its eye stalks. And you can see the optic nerve being blown out along with it. So it's quite an amazing process. Mouth parts are also found on the head. Well, when they have mouth parts, this fly doesn't have any mouth parts. It's an adorable fly. Therefore, you know, something's bad about it. Yes, this is the reindeer bot fly. So absolutely cute, but it has the larvae which I affectionately call the snot bots. Because guess where they live in the reindeer? There. Now the adult does not feed at all. It may have a sip of water, but that is it. Because it is the larvae that is basically solely there to feed and provide enough nutrients for the adult stage. Now these adults migrate with the reindeer. They can migrate, the moose one migrates with moose. So you're talking, you're tracking them for hundreds of kilometers. There's some horrific experiments where they glued them to a piece of string and made them fly continuously to measure how long these can go for. And it is kilometers after kilometers. But in the museum, we have some micro CT scanners now. And so this enables us to look within the pupil, within this hidden stage of the development of what's going on, which we couldn't do before. We didn't know whether it was a continual progression or stops and stops. And it is stops and stops. But we were also curious to see what was happening to the internal structures. Now my colleagues, they got these botflies. This was a sheep nasal botfly. And they wanted to see what was going on. Now the larval stage, it is basically also livery glands and guts. So everything about it is designed to actually consume and lay down all these loopholes. And then during the puparium stage, these stages here, before it was merged, basically this, it just disappeared completely. And in some skies, the guts don't even link to the mouth parts anymore. The mouth parts are purely there for looking pretty. They have no function whatsoever. So it's amazing that they've done this. But as most of you know, they do have mouth parts and some have very long mouth parts. These are amazing. So everyone knows about Darwin's moth and the longest mouth part and how it helped with the theory of evolution and everything. It's good, but it isn't a fly. And in body length, this fly's mouth part is one of the largest in the insect world. So if it was a human, your tongue would be six meters long just to put it in reference. I like the way you stuck your tongue out there. And for what they can't do unlike butterflies and moths is they can't curl them up. So what this does is this ratchets it underneath and flies with the mouth part dangling out the back of it. When I saw them in South Africa, I did have to take a moment not to giggle because they do look quite ridiculous. But they have co-evolved with many of the plants. And in South Africa in the Cape, it's known for its flora and one of the many reasons is because you've got a truly unique population of flies there. And if this fly was to die out, eight species of flower, eight species of plant would go immediately. What I like about them is a lot of them are specialist pollinators of Erica's. I was like, ah, isn't that nice? This is our version, which is very cute. This is our beef fly bombillius major, which is my what I call it the advent of spring. It's why I'm late for work the whole of April basically because I keep seeing these in my garden. And what they do is they too can expand their mouth parts. So they are able to get really deep into the flower, into the stems of the flowers to get to the nectar. So they really are important early pollinators. And it is quite amazing to see them. Some of them are thieves. There's no getting around it. Some of them won't bother. Just was stabbed through the base of the plant, which is quite sneaky. But they look so adorable, we let them off. There is a math part that we don't like to let off. And that is the mosquito. And a lot of people don't like this. Now, you got to remember, she's a mother, okay? She's driven to do this for the sake of her unborn children. And I got to put that in your head like that. Because only the females are blood feeders. Basically, this is the same with most of the blood feeders. The only other example where they're not is the taxi flies with a male's blood feed as well. But it's always the female, every other case, because she needs the extra nutrient for egg development. Not all mosquitoes blood feed. And most of them will only need to do it once. But it's been quite interesting when you look at this. And clever people have looked at mosquitoes and thought, you know what, we don't actually realise when they're actually biting us. We only realise afterwards when we have a reaction. So how on earth is that happening? And is there something we can think about this when it comes to medicine? So what they did is they looked at what was going on. Now, this is really quite cool. And maybe a little bit creepy for some of you. But the mouth parts, the bit that comes underneath the stylet, it moves around underneath your skin. Because at the end of the mouth part, they've got sensory receptors that are able to sniff out the blood in your capillaries. So it can move around and miss all sorts of amazing things. Now remember, this mouth part has got no muscles in it. So all of the action is being controlled by the hydrostatic motion and by the mouth parts. She's got several pumps in her head where she controls the delivery and the uptake of what's going on. So she can deliver the antihistamines, the histamines, sorry, and she can get anaesthetics. She can deliver all that and she can take out the blood. But what else is really important is that when she pierces the skin, she doesn't just pierce it, she's basically got a pneumatic drill. So she will do that. And she's able to pierce your skin with so much less force. I believe it's about 400 times less force than if she was to just stab her mouth part in like that. Now, we've been suffering a pandemic recently and everyone's been having injections. And they've been thinking about this because the phobia of injections and they're now developing smart needles based on mosquito mouth parts. So next time you get pierced by one, just say, thank you, have a little bit of blood and it'll be okay. But it is quite amazing how we're using them now. They're also using the oviposter, the egg-laying tube of wasps. So I don't know which is the better one to have a needle developed from. The final sensory organ on the head is the antennae and neither that is. Talking about mosquitoes, mosquitoes have what we call a cocktail effect. So a male mosquito, if he's in a room, you know when you're at a party and you can hear your name being mentioned at the back of the room and you can zone out all the other voices and just hear what's being said about you. Well, if a female mosquito flies past the male and she has picked his interest, he can cone out everything else, completely zone it out and figure out her because they've got amazing sensory. In fact, the hearing on a mosquito is a lot better than ours. They have at the base of them, these Johnson's organs that are enabled them to hear much better, but they've also developed strange annotations on the antennae. We've got these pappals here. We don't know. I mean, we assume that they, you know, they reflect that good with sound. We know these are very good. It's a, this is a kind of, this is a punk fly, a parasitic fly and it's got a bowl inside of its head there so it's able to again concentrate the noise. And then we have these ones which has really long antennae. So these don't use their antennae for listening. They use them for territory guarding. So these are midges. These are very, very old flies. In many ways they're kind of like sisters to the rest of us. And they don't land as adults. He's not alive for a long time. It's a male adult, but he will hover over the stream where he wants where the female will come and lay her eggs and he will guard his territory with his antennae. It's rather sweet. But not all of them have antennae on the head. We moved into the abdomen, a thorac, sorry. And this is generally where we consider the locomotory organs. But this is again, this is another punk fly, this is another parasitic fly and it has, is this going to work? No. See this fat summa segment, this orange segment behind its eyes, near the spherical, near the hole. These are unique to this fly and these are like a hearing aid. Now the fly is very small. So it's very hard. It's like we've got a nice big gap between one ear and the other ear. So we were able to triangulate very nicely where the noise comes from. Fly is a small, really small. And so for it to triangulate, it's not really going to do that. And again, this fly is after grasshoppers, the crickets and very fast moving insects for which to lay its leg in. So it's developed this resonance thing, which basically it's seesaws in it and it's able to amplify the sound. So it is able to properly over really long distances for it like 30 centimeters, huge distances for the fly and mimic to amplify the noise. Now again, this is technology that we've looked at and they're developing very, very small hearing aids based on this. So instead of a big clunky thing, you can have tiny, tiny hearing aids based on a fly's shoulder pads. But the rest of the thorax and tract muscles body fell in hairs. It's a problem if you're identifying because we have to identify them on their hairs. Hairs facing forward means it's a different fly from hairs facing back, which is great when all the hairs are falling off. But the hairs are very important. What for? We don't know in 99% of the cases, but there's some really lovely cases where we do. Now not only is their body covered in hair, their body's covered in cuticular hydrocarbons, these lipids, and they're amazing. And they change with the age of the fly, the sex of the fly, the species of the fly, all sorts of things. But they also combined with the bristles enable flies to go scuba diving. Now lots of insects go diving. We see this all the time, beetles do it. Everyone knows this, what's so important Erica, it's crazy. So this fly is able to scuba dive in the mono lakes of California. And if you know these lakes, they're the most saline environments on the planet. And salt disrupts all the chemistry normally on the surface of the insects, but not with this fly. So not only is the chemistry helping, but also the shape of the bristles. And as physicists have discovered, the angle in which he penetrates the lakes and they do it at a specific angle every time. And what she does is she hits the water, she crawls down and she lays her larvae at the bottom. Now larvae are fine, they can survive in these environments, but nothing else can. So they've got loads of dead food to feed on. So this is brilliant. They've got no predators, they've got loads of food. And once she's done that, she lets go of the bottom and then she's like, wing, out she comes. Which would be amazing. I'd love to see all these flies topping out the water. But what I find really, really cool is that her eye is not covered. And I don't know, we don't know why. So obviously it's good because she can't see it. So she can see, but how did this happen? Why does the eye not need to be in the plastron? Flying is unknown for flying. This is definitely something they're very good at. And they've got amazing wings. This one obviously has got huge wings because it's male and he's showing off. And this is the New Zealand cannibal fly. It's not a cannibal. This is a game why you shouldn't listen to common names. But these, these are our common flies. I think all the whole fly is more known for flying. Next and third fly. As I said, they do huge migrations. We are now looking at them migrating across Australia, all across America and Europe. Some even fly from Northern Africa into the UK. So we are seeing quite amazing things. In fact, first animals into space was a fly in 1947. So a client like that. But not all of them fly. Some of them don't have any wings at all. This is really cute teddy bear. It's an ecto parasite, which means it's not a true parasite, sorry, it's a klepto parasite. It's an ecto-plepto parasite. I can't say that after a few whiskeys. And what it does is it lives on the back of a queen bee. Now, many of you males with beards, I think you should really appreciate these things because what they do is they come down and feed around the mouth parts of the queen when she's got her food all over her face. So they're really little, lovely little clean image she. But isn't it amazing? Like the size of them, that's like a hand walking all over your body. So how on earth does the queen not throw them off? Again, it's down to these hydropaths because these have basically got essence of bee all over them. Whether they mimic it or whether they smother themselves in the queen, we do not know yet, but they smell just like her. Hence why she doesn't get rid of them. We've got rid of them though, because we put miticides in all the beehives, didn't get rid of the mites, but they got rid of these. Luckily, they're making a comeback, which is nice. These are my favorite parasites. They, I mean, look at them, adorable. And I spent all day, day-to-day, on the way up here, I was cleaning up images of these flies, I love them. Now, these are, again, wingless flies, and these have gone back. This is the one that's made into the wildlife photography of the year. It's like, yay, excellent, they have some flies in there. They're not usually this big, I have to say. And these wingless flies are amazing because they've got no wings. The thoracic muscles have just basically disappeared. And so when the fly is not feeding, the resting stage of the head is pinged back against the abdomen, thorax of the fly. Look at their claws. They're perfectly designed to live on these bats, to hang on. These are ones I collect in the Caribbean, kind of little cute fatties. And what is amazing about these is they give birth to live young. So we generally think of this as a mammal thing, but these are truly, they get pregnant and they have internal lactating glands. So they would give a milk-like substance to feed their offspring. So they really are quite amazing mothers. Look at them. I think they're quite cute. When you find them in the world, bats get really angry really quickly. And these basically look like drunken spiders. So you're trying to pick them off with forceps. There's an angry bat squealing at you. There's students all around you. You're trying to be professional. It's 11 o'clock at night. It's not the most adult or field work. Moving on to the legs. Legs are brilliant. They enable them to walk around when they have legs. But they also have all sorts of strange structures or other things. This is a fly I've just described from a Caribbean. This is a house fly. Got very hairy legs. I named it after my friend. She's got very hairy legs. I don't know if she appreciated me, but that was my wedding present to her. But they also have different uses for their legs. Well, there's a lot of flies, especially when there's in this group called M-pids and Dolly's do it as well. They give gifts, not your gifts. The way to a female's heart is to feed her. And in many ways, it's like a analogy of a box of chocolates. So it used to be that they would go up, he'd find a fly, give her a fly or something else. She'd eat it. He'd have his wicked way with her and everything was brilliant. But not always because many a time she fed too quickly and she would leave him mid-cop. I was gonna make a joke about last week, but it's not pretty. And so the mouse had to figure out another way of dealing with this. So what a lot of them did was they developed silk glands. So on their legs, they've got these silk glands. These expanded acetarsis in their feet, which he will produce silk. He will catch something and he will wrap it around. So now he's given her a box of chocolates. He's all wrapped up and wonderful. And this is great. And she will feed and it's brilliant. But now you've got the opposite happening which has taken too long. He's like, ah, finished. And some of the cases, he takes back the half-eaten box of chocolates and re-wraps it. Brilliant. Evolution happens. Things develop. Mowers have gone, hold on. Why do I even bother to find a fly? I'm just gonna give her an empty ball. And now you've got these saliva balloons that a lot of these flies give. So they're completely empty. Some of them will stick things like diatoms in, bits of algae to make them look pretty. And nutritionally, you could say there's a little bit to gain about saliva, but it's not a lot now, is it? Well, at least that's something because there's another group, Ransomaya, which you've got some here in Scotland. They have gone even further and they've gone, you know what? We're gonna let the ladies do the work. And we do not really see this in the animal kingdom where the females have a secondary sexual characteristics. Us humans do, but in many cases, it's always the male showing off. So in these flies, they have what? They've got massive wings. The females have got really hairy legs and they've got a massive abdomen because a massive abdomen shows the male that she's really become. For example, this is a Stratiomyod soldier fly and her abdomen is wider than she is long. Can you imagine that as a bottom? It's fabulous. And it shows she's gonna be an excellent mother, apparently. So, and I do like these, these are Stratiomyod. They do make these fat bottom flies. They make my rocking well go round. Now I've got that stung in my head now. So we're on to the abdomen, the final bit of the insects of the fly. And this is basically the most important part because this is where the reproductive organs are. But there's also some sneaky stuff going in there. And one of them is found in the larval stage. So this is in New Zealand. This is a group of flies called Keroplatids. They're a type of fungus mat. And in their version of kidneys, the mouth figure and tribules, they bioluminesce. And this is a unique bioluminescence to them. It's not the same enzyme as you find in other bioluminescent creatures. And also, because they're flies, they always come with a slight something bad is gonna happen. And what they do is they dangle these balls and these balls life anything that comes into them. So they would dissolve food. So they're fishing. They're attracting them with a lure. They're fishing for them. And they will gradually pull up this decomposing these half-dissolved creatures to feed on. Now they're highly territorial. So if another larvae goes up to another larvae, they will try and eat it. And these are the famous glow caves of New Zealand. My mom came back and all I saw these lovely things and I'm like, ah, there's a fly. It didn't take me. But I'm a fly person and we're always talking about genitalia. And it's not because we're weird. It is because of some very important thing because genitalia is basically the first thing to change when you have new species. When it comes to morphology, which is why we look at genitalia. Now, if you hang around fly people, fly people are always like, females are really boring, males are where it's at. And they're talking about flies, obviously, but it becomes quite painful after a while. So it's always nice to highlight when there's some really good ovipositors out there. And the ovipositors are the egg-laying tubes. Now this is a true fruit fly and these have this huge ovipositor and that's it in a resting position and she will lock it into shape when she's about to lay her eggs. Now, what is amazing about this is you have this hidden world going on, but at the end of her ovipositor, again, you've got, it's a chemical sensors and she's able to prod through the fruit or whatever she's laying in to see whether it's good or not. And some of them will leave chemical signatures behind to tell the other fruit fly ladies, come and lay your eggs here. This is great because the more they can get in, the greater chance if they get attacked, that one of them will survive. So it's to building as many. But we do have to talk about males because they do have some extraordinary genitalia. Yes, this is the penis on a fly. They have, I think these are these curly whirling machines that you get in doctors and dentist surgeries, the ones that buzz. This one is shaped like a corkscrew. It's quite nice. You can open bottle of wine with that one. And this has enabled some extraordinary sperm wars with inside the female. So there is amazing thing going on. So she's trying to kill as much of his sperm as possible. He's trying to get his sperm up there as further as possible to get rid of all the other sperm. And this has resulted in what's called mega sperm. So your fruit flies are quite exciting. That fruit fly flying around, it's a three millimeter long fly. It's got a one millimeter, sorry, sperm, which is huge. This is his cousin, Drosophila bifurca. Again, it's a three millimeter long fly. Her sperm is 5.8 centimeters long. So that's the equivalent of a male producing a sperm whale, which is quite shocking if you put it in those sorts of figures. But it is because there's so much competition. And it's not over there. If she does get pregnant, and these are your little bat flies again, some extraordinary things can happen at the final stage. So she, this is a, and remember, don't trust me with a smiley face, because a smiley face usually means you're looking at the bottom. And yes, once more, you're looking at the bottom. But she's got pregnant. She looked like a normal fly to start with. She's got pregnant. She stuck her head into the side of the bat. She's then ripped her legs off or ripped her wings off first, ripped her legs off, and she has imaginated her abdomen over her head. That is what she looks like now. That is an extraordinary adaptation to go through. So this is it, flies are extraordinary. Because they get everywhere, they can do everything. Their morphology is amazing. This is a marine fly that rows around. It's got paddles for wings or wings for paddles, front legs for oars. It's an extraordinary creature. This is one of my favourites. This is a UK species. This is a robber fly. Everything about it is designed to be the apex predator it is. These are even venomous. They have new venoms to science. The family name is acyllidae. The venoms are called acylins. So you can now know 10 venoms, because they're called acyllin 1, acyllin 2. It's very... Look at them. And a lot of them even have moustaches. And I think this is very nice as a female of a certain age. So they're absolutely adapted to being predators. In her 2017 work, The Secret Life of Flies, the entomologist Erika McAllister estimated that for each person on Earth, there are how many flies? The figure in question is about the population of Zambia or the Netherlands. You can have 3 million either way. My phone went berserk at this point. 6 million? No, it's 17 million. Amazing, isn't it? It is amazing. And that's the thing. Now, there are so many flies. There are so many different ecological niches. There's so much we have to learn about them. So my parting thing is to please go away, have a look in your garden, have a look in your house and have a look at their amazing morphology and really become to understand their ecology. Thank you. Thank you very much, Erika. So now we're going to have a very short break so that the people at home can type their questions into the Q&A. And the people here in the lecture these last in a couple of minutes can also ask questions. OK? OK, Erika, you're welcome. Do we have any questions from the audience? Do we have questions from the audience? If you just put your hand up. We're seeing that flies in this situation are so seeded and sorted. How long does it take to become a flyer? Oh, let me just repeat that. But if you can, I'm going to have a question for you. Will you come and help me with this? So you're asking how you can kill a clad and not a horsefly? OK, number one, the same things. Horseflies, clads are horseflies. But it's interesting because you get different ones flying at different angles. You've got females coming at you. I guess if she feeds slightly differently, she slices your flesh and laps up the pool in blood. So she's got a slightly different mechanism and she's a little bit more cumbersome than a lot of the other flies that you're trying to swat. And she's attached to your body in some way. If you come behind her, she hasn't got the same vision in the same way. The males have got all the head. It's haloptic. It's all eyes so they can see all around. Again, with the mosquitoes, they've got much better vision behind as well. So I'm guessing she just can't see it in the same way. I haven't killed horseflies, young man. And you shouldn't be doing that. But it's worth having a look. They did a lovely investigation recently where they dressed horses up with different coats to see whether the horseflies could see them. And what they did find is that if you were probably actually Maggie, and the lady behind you and the red, you're probably the most appropriate act not getting bitten by horseflies wearing that. Because they like dark colors. So if you go out looking like a zebra or you go out with spots, they find it really difficult to differentiate. So it's the change with the darkness and the lightness. So things like that will impact them. So maybe it's because you've got dark trousers on, but a light top. You should wear different clothes and find out. Go sacrifice yourself with science. So you're asking about the bioluminescence in these predatory larvae. Now in the actual larvae, it's not the dungy bits, the bioluminescence. So they have, although they have an open lint system, so it's not like us with the closing system, they still do need to filter. And their version of a kidney, so it's not totally like us, is what's called the Malfigurian tubules. And it's in that, that they've got this bioluminescent chemical reaction. Are they spinning else? No, that's in their body, but it glows. So the dungy bits sparkle. And the moths are like, oh, oh, look at that sparkle, sparkle. Dead. OK, one more question from the audience. I'm so very interested in the eyes of the client. I'm not very well-meaning, but my question is, what is this, the same personal reaction of the client who's been discussing all this for a long time? And I think, is that before the movement of the client is in the sphere of a wheel, through something like pages or something, and growing the world of human substances or whatever, growing the way the chain is fractured all the time? Well, a lot of the insects, I mean, sort of seem to be the same thing. Just the student behavior, with the substance, and I don't want to take any of the reaction of the wheel, but I'm just wondering what the insects are. Yeah, so the whole thing is, a lot of people, when we associate with flies, we do think of them being disgusting, in comparison to the other insects. And one of the reasons is that a lot of flies are very amphiphylic. So they will hang around with us. And so therefore anything, our waste, our dirt, our food, these flies will be attracted to it. And these have co-evolved alongside us. The same with a lot of mosquitoes and things like that. And it's a shame, because you are only talking of hundreds of species, when there's hundreds of thousands of species out there. So in the UK, there's over 7,000 species of fly, but there's only 20 that are very, very closely associated with us. And it's a shame as well, because in our garden, there's another 20 that we desperately need. So we have for many years concentrated just on the negatives. If you think about butterflies and moths, they're larvae of vicious caterpillars, eating our crops, eating everything. But everybody forgives a caterpillar when it becomes a butterfly. And these is, we do this, we've got this really quite negative bias. And I think at the mount time, we just dropped that. You know, it's one of the bias, it's just money. And this one thing, how do you do it as with what I'm trying to do with it? Yeah, I mean, why is it? I said that flies have a major vision, yet still flies keep caught up in spiders web. It does remind me of David Attenborough once doing some filming with bats, and they were talking about how bats are amazing with echolocation, and one flew straight into his head. They will, sometimes they will get sidewiped by something. Now, you've got to remember, they're flying in 3D, so they're having all these different things going on. And when they're flying, they're not just seeing, they're smelling, all of this. So they would get disorientated quite quickly. We talk, you know, everyone goes, why do they always fly into windows? Now, the thing about glass, it will stop, is it UVA and UVB coming through? And flies use that to orientate. So depending on where they are, in different situations, they will just get, you know, and maybe they were just flew up too fast and just went into it. So yeah, there are some actual flies that have learned to live on spider webs, though. So even those environments, some flies have adapted to it, it's quite fun. And then you, in the second part, where you say, oh, glass, this is how you do it, it's quite clear, it's a different situation. And the second part is, is not something that goes online, it's a kind of operation, perhaps, where we should be able to find the glass. Yeah, actually, somebody else has asked online. There's an online question also on climate change and flies. Now, number one, we don't know enough about flies. So we're the most described country in the world. We know there's 7,000 plus fly species here, but what we can tell you about their love, even most of their species, is nothing. Okay, so they've looked at long-term changes when it comes to lots of birds, lots of vertebrates, fish, and as we get smaller and smaller, it gets less and less. And most of the insect populations they've looked at has been ground beetles, butterflies, and some bees. So flies have been ignored. Recently, thanks to the use of UK recording schemes, such as the hoverfly recording scheme, they've been looking at long-term data shifts, and there's been these tracks set around the UK called the Rothamsted tracks, and they're looking at the aeroplankton. So we're beginning to get data. Now what they're showing us, which is actually pretty obvious, is rare species becoming rarer because they are the ones whose habitat is quite unique. They've evolved to be in those habitats. They're the ones suffering. So with a lot of the very rare hoverflies struggling badly now. But a lot of the common flies, like those hoverflies that are migrating across Europe, they are doing well because they are able to still carry on to find nectar to do this. And the nice thing in some ways about flies, and Harrison says bees, is that the larvae feed on a completely different thing to the adults. So whereas bees, the larvae will be feeding on the pollen and the nectar, which we impacted, say by pesticides as well, and all these, you won't get the same difference in the flies in a lot of the cases. So climate change is having an impact. We're seeing species kind of moving, but the true extent of what climate change is gonna do, we don't know. And I have a nasty feeling things may happen too quickly for us to actually realize what's going on. Okay, one final question from, in the hall. Yeah. Yeah. No. Yeah. So the question is that the UK is, has always been slightly different than the mainland Europe. And we are a really managed country. If you look at our ecosystems in the UK, we are way more land is turned over to that, really intensive farming. So yes, we are being known for being bad to our insect populations for a long time. And it's something we really have to readdress. So land use change is the biggest problem with insects. So climate change is about fourth, fifth at the moment. Land use change of pesticides, number one and number two. So those two factors have to be addressed. Okay, we'll now take some questions from the virtual audience. And now I'll read these out to Erica. One member says, I photographed the wings of flies for fun. And I've seen that they've covered in tiny hairs. How does this affect the aerodynamic properties of the wing and what are those hairs for? Ooh, you're gonna have to ask a physicist about that. We don't know, there's a lot of hairs, but not all of them have hairs. Some have scales, some don't have scales, some patterns of scales really change. But they are not just for flying. So they've manipulated the genes of Drosophila, they do it everything. And they've got rid of the sensors at the top of the wing. And this means although they can fly, they can't smell because they use their wings to smell as well. So this enables them to go up to fruits and things like that to determine what's going on. So when they've turned the genes off at the base top of their wings, these things are flying blind now. So yes, we know that they're not just for flying. Okay, there's a question about flies in the marine environment, which are not so common as they are in the terrestrial environment. And yet you did say they could live in salt water. So why? There's a fly I showed you tonight that lived in marine waters. So flies never evolved in the sea. Insects didn't evolve in the sea, they didn't come from the sea, they've gone back to it in certain environments. So we now know that fly insects basically have come out of crustacea. So the crustacea stayed in, a few came on land and the rest of the insects on land developed and went woo-hoo, a brilliant environment. So there's also, the marine environment's quite poor, but we've got loads of, there's some mosquitoes that have gone back, there are coronaments that have gone back, there's these midges that have gone back, all sorts of things, because it is still quite a good habitat. Okay, there's another question about fruit flies that have a pheromone along with their eggs to attract other females to lay on the same fruit. Does that attract only females and of their own species or might other species say be attracted to it and eat the eggs or whatever? Well, yes. I mean, that's the whole thing, develop chemical and it will be manipulated by everything. We are trying to mimic those chemicals now to use for integrated pest management. So we know that that chemical is meant to be species specific, but other species have recognized it and they will come along on a date. We want to use it to actually tell other flies that this fruit is not good. So everyone is looking at these chemicals in a slightly different way, but they are meant to be species specific. Right, another question. Are there any flies which are builders in the same way as the wasps and bees? Are there any that build structures? Oh, I've never been asked that question. Are they really the failures then? No, no. Some of them will create amazing cases for their larvae. So some of them make beautiful little cases out of larvae and structures like that, but not many of them because they're not social in the same way. So that's where you get all these big mess. There are some beginnings of use sociality. So there's a New Zealand backfly where they live together in a roost, but it's basically in back poop. No, it's not exactly like romantic, but the older males will guard all of the nest and they would zzz at things coming in. I don't know how that's meant to work as an antipodation, but that's the closest they kind of get to use sociality. So they're not builders. Some of them will create amazing webs and do things like that, but not the buildings. A question about the fly brain. How smart are they? How smart is a human? So we've mapped the brain now as I think it's 100,000 neurons and they're now beginning to look at all the neurological pathways. It's not my area of expertise, unsurprisingly, but they are beginning to realize that they are doing, they're storing a lot more memories than we thought they were and they're adapting a lot more. If you traumatize a larvae in a certain way, it will remember when it's an adult, because this is a horrible experiment. Don't do this, everyone, it's horrible. But they are looking at all the way they do this and how they can communicate. And so obviously we want to know whether they have a conscious, whether they get upset about things and I don't think that's ever gonna be the case, but we are now realizing there's a lot more going on than we initially thought there was. Okay, question about flies walking on the ceiling. Yeah, how do you do it? How do flies do it? Well, they're amazing. So on their feet, they've got claws, they've got hairs and they can release a substance that enables them to stick. Now landing on the ceiling is not the hard thing. Pulling off from the ceiling is the hard thing. Okay? I don't think I could walk on the ceiling. And they do it in an amazing way. Actually, if you look at their gates, it completely changes when we're walking upside down. Honestly, go look at flies on ceilings. Hours of fun, especially when you're in a pub and everyone's like, what are you doing? Slicking the fly. So they change their gate to stabilize because that was better when they're upside down and they will walk slowly, but they will pull off. So they push down and pull off in a certain way to enable it to peel off. So we are looking at this because we're trying to develop robots that could do that. So everyone talks about the geckos and things like that, but you've got these things flying around your living room that are brilliant at doing it. I, my Who's the Pest Radio 4 series, they gave me these like suction gloves to act like an insect. The dangled off the ceiling, which I did for a couple of seconds before my weight just went to both. But it was quite extraordinary feeling how an insect might feel doing that. Okay. A question I wanted to ask you about, it was a question earlier about why do people, blind flies, disgusting? Obviously you don't, but also people, even entomologists sometimes are rather to me insensitive about the way in which they will trap flies, trapping them on sticky flies. I don't like that. And I just wondered what you thought about that. Well, I think it's inhumane because you are starving an animal to death. And I think if you use the word animal instead of fly, people suddenly look at it differently because it is an animal and it is a nasty way of doing it. So it's interesting because obviously I think around killing a lot of flies. It's my job. But we've actually done a lot of ethics involved in studying, which is the nicest way to kill them, which is a terrible conversation I admit. But because that sort of thing is, I just wish it banned, it's awful. You see there's adverts where you could just go around zapping and spraying all of this. And it really doesn't make us understand what is going on. So I teach people how to catch flies. If you want to catch a fly and you want to swap it, actually just go really slowly because it can't actually perceive the movement. So you can do that. It's like if it's bothering you, just gently catch it and let it go out. But just take time instead and look at it because you've got a wild animal flying around your living room. Which I think if we change our perspective for how we look at these animals, it'll be so much better for us in the long run. And the fact that many people feel flies carry diseases? Humans carry diseases. We are walking pain. We can see this at the moment, the fact that we're all wearing masks. I mean, you've never actually been killed by a fly. I'm still alive. Yeah. You haven't been killed by a fly. They are very good transmitters. I'm not going to disagree. But there's many things that we can do to prevent this. Many obvious easy mechanical ways of breaking that. So if we just, and in the UK, we're fine. So we just need to think a little bit and less about just trying to kill everything immediately and understand what's going on. Maybe cover up your food. Maybe shut that window. Maybe do things like that because they don't perceive your house as your house. You built your house in their environment. Okay. I think that's the end of the questions, at least the ones that I can see. So first of all, I'd like to apologize to the virtual audience. There was obviously a problem with the viewing of the speaker. It didn't transmit properly. I'm sorry about that. We'll try to make sure that doesn't happen in the next hybrid lecture. I'd just like to end by thanking Erica very much. Thanking also the audience who've come along. I know we weren't allowed to have very many, but thank you to the audience. But any special thanks to Erica. I hope she's changed your view of slides a bit that you might be interested in their diversity, which is what she's talked to us about. The fact that there are so many potential inventions that we might make on the back of what flies can do. We've got a lot to learn from flies. We've got a lot to learn from many animals. I hope you might think twice before you swat flies in future. And maybe you'll spend your evenings watching them walk across through a ceiling instead. So thank you very much, Erica and I'd like the audience to thank you. Thank you.