Erica McAlister: On the Appreciation of Flies

Dr. Erica McAlister of the British Natural History Museum recently released The Secret Life of Flies, an exploration of the more fascinating side of the fly (Image Credit: Erica McAlister, CC BY-SA 2.0, Image Cropped)

The Norwegian ForBio conference occurs once a year, and brings together a large collection of biosystematics experts from the Nordic countries. Biosystematics being a bit outside my field, it’s not something I’d generally attended, however this year it was 250m away from my office, so I considered attending. But what tipped me over the edge was the presence of Dr. Erica McAlister of the British Natural History Museum, who in late 2017 published The Secret Life of Flies, a brilliant expose on one of nature’s traditionally less sympathetic taxa.

Erica’s talk was fascinating, replete with stories of lost artifacts, mosquito sex and David Attenborough. Afterwards, I got the chance to sit down and chat with Erica about everything from the problem with honeybees, to the beauty of mosquitoes to issues with a certain Jeff Goldblum character.

Sam Perrin (SP): You’ve spoken today about flies being the most important insects on the planet. Can you justify that?

Dr. Erica McAlister, Senior Curator, Diptera, Natural History Museum, London (EM): The ecosystem disservices and services they provide are absolutely pivotal in terms of impact on humans, on our agriculture, our livestock, and shaping our environments. Mosquitoes have a very negative reputation, but all the males are pollinators, so that’s half of them! We don’t tend to think of flies as pollinators. Of the 160 or so families of flies, half of them have pollinating species, and in many ecosystems they are keystone pollinators. Many bees don’t like the cold, so in many ecosystems the flies have to do all the work. At high altitudes you have bumblebees, but you also get hoverflies. In ecosystems like the Arctic tundra, the flies are hardier, they’re the ones doing all the pollination.

The evolution of flowering plants! Recent papers have come out and they’ve shown that the evolution of flowering plants happened alongside flies, as well as the Hymenoptera (wasps, sawflies, bees), but the earliest long proboscid animals were flies, and plants have evolved to be able to utilise them.

But think about what everyone associates flies with. Decomposing, getting rid of dead bodies and faeces, imagine the environment without that. It’s not particularly pleasant. So you want them as pollinators, you want them as decomposers, you want them as predators, because they get rid of a lot of species that we don’t want. The larvae of hoverflies, the adults are pollinators, but a lot of the larvae eat aphids. They are the best friend to gardeners.

So we have to understand them more than we do. They are very useful for forensic entomology, they are used for maggot therapy, they’re also used to feed the world. The black soldier fly is going to basically feed all our livestock, and humans too eventually. They’re really protein rich creatures. They’re even being use to understand our genetics. Inherited disease studies use flies. They basically rock.

SP: So how do we turn that fascination into genuine concern for these species?

erica and laphria

“…people don’t know how fascinating [flies] are. You just need one conversation, you just need one stimulus and you can get people involved. ” (Image Credit: Erica McAlister, CC BY-SA 2.0)

EM: I think a lot of the lack of attention to the problems with fly populations is because people don’t know how fascinating they are. You just need one conversation, you just need one stimulus and you can get people involved. For example, it’s the Year of the Fly internationally. In the UK we’re doing bee fly watch at the moment, and we describe these bee flies (the family is Bombyliidae) as gateway flies, because once you get people looking at them, they start really paying attention to everything else. And it’s an amazing creature. The adults are pollinators, they look like fluffy flying narwhals, and the public lose themselves over them. They’re so adorable. And they’re parisitoids, so they’re quite gruesome and quite fantastic. But then people realise, this is their garden that the bee flies inhabit. They don’t have to go on safari, they can see fascinating creatures in their backyard. And we’re running more citizen science or activity science projects to engage the public with them.

SP: There’s been a lot of concern for pollinators lately, but that concern often gets focussed on charismatic species like the honeybee. Is that a problem?

EM: The honeybee is not a good pollinator in most situations. It’s not specifically adapted for most of the wildflowers in certain regions. But engaging people with all the different pollinators is a problem. So we often use the honeybee as an umbrella species. By doing this you can conserve lots of habitat, in the name of the honeybee. And you’re actually helping lots of other species too, which helps the crops.

I don’t necessarily like it in some ways, because it’s not giving credit where credit’s due. Of the top 6 pollinators in the UK, 3 of them are flies. But if the honeybee helps get a really easy message across then fine.

SP: You’ve recently published your first book, The Secret life of Flies. Is it something you were asked to write?

EM: Yes, somebody heard me give a sex show on insects and said “you’re very funny, can you write a book?”. I didn’t know, I’d never thought even about it. So I said I’d do it on flies, and then the Museum said yes, definitely do it. I didn’t expect it to quite take off as it did.

SP: Was there any trepidation involved?

EM: Massively! I’m writing book number two at the moment, and it feels even worse. I was asked to write that one too, I’ve now I’ve got this horrible second album syndrome. I hate it, my nerves are gone.

But it’s good to get it out there, because so many popular science books are quite biased. It’s great to get the public thinking about more interesting species. I’ve just been on a BBC Wildlife Magazine readers’ week, and they had lots of wildlife history people, and I’m one of only three only insect people. And we’ve got so much popular science about birds, mammals, bats, but nothing about insects.

SP: Onto the important questions then. Could the world survive the eradication of all mosquitoes?

EM: They’re really important in food webs. You’re wiping out three and half thousand species. The absolute abundances in aquatic ecosystems are enormous. You probably could, but I don’t see what the benefit would be. The whole thing about getting rid of vectors, is that things like the plasmodium which causes malaria will try and find something else to take over at that point. So you don’t necessarily get rid of the disease vector, to do that you would have to shut down the disease or the plasmodium. So we’re focusing on the wrong thing by eradicating mosquitoes.

They’re a fascinating organism. There’s a genus called Sabethes, where the males have leg warmers, and they dance for the ladies, and it’s truly exquisite. There are mosquitoes that live in crab burrows and only feed on birds. The males listen for the females when they are about to pupate. They listen through the surface of the water to sex the females. It’s amazing ecology.

SP: You spent 3 weeks in Java on the sides of a volcano looking for a species of mosquito. You eventually found it in a puddle. When did motivation dip?

EM: Well you start off thinking “it’s just a mosquito, of course we’ll be able to find it”. And then you see the size of volcano, and doubt sets in. Then a week in, you remember you have research budgets and financial constraints, you’ve got time constraints going on, and they’re beginning to play in the back of your mind, and the stress kicks up a gear. And all your friends at home are laughing, because how can you not even find a mosquito? And you question yourself, especially when it’s 11pm at night and you’re really tired, and you’re going into farmers’ sheds to hoover mosquitoes off the back of the cow.

This is a terrible story. I was in one such shed and the bull trying to… let’s say get friendly. I was tired, I’m dealing with a randy bull, I’ve got what looks like a ghostbuster kit on my back, and then I find out that the farmer had lit a fire earlier that day, so he’s fogged the place and there’s no insects in there anymore anyway. And at that point you think “I could be in a pub in the UK with my friends!”. So yes, it dips. But when you find that species, it’s all forgotten, absolutely all forgotten.


David Cronenberg and Jeff Goldblum did nothing to help the fly’s public image. But did they get the science right? (Image Credit: The Fly, 1986)

SP: Lastly, do you have any strong feelings about the film The Fly?

EM: I do actually. I was asked to look over it and see how accurate it was. We broke it down into feeding, reproduction and locomotion. The feeding was quite good, however only the higher flies, (which I guess it was, because it was a house fly) who vomit like that and release digestive enzymes directly onto their food. So I quite liked that. Locomotion? Well he was climbing up walls, that was interesting. He would have needed an extra pair of legs, but I’ll let him off. He didn’t fly as such, but I don’t know how he would have. The reproduction was quite entertaining. Because as an adult, all he should have been doing was reproducing. That would have been a bad film. A completely different type of film. Maybe not one for the general audience.

I also got asked to describe the sex life of aliens once. They described an alien to me, and said, how do you think they would have sex. Quite an entertaining use of years of education.

You can find The Secret Life of Flies online at Book Depository and most other online retailers.


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