What’s so special about insects!? - Blooming Green - Seasonal British Wedding Flowers

What’s so special about insects!?

Did you know that this week is Insect Week 2022? (June 20th-26th)

Recently we were lucky enough to interview Dr Erica McAlister, senior curator at the Natural History Museum, and also a very old friend of Bek’s. An initially reluctant group of children were given the task of grilling her and started with the slightly confrontational question: “So, what’s so special about insects?!” Little did they know that Erica was about to blow their tiny minds with curious facts, amazing stories and a few tales that would make even their parents blush… (Image above: by Brie Harrison)

So, what are the insects going to be doing for Insect Week 2022?

I can’t tell you most of the things they’ll be up to! This is the time of year when you will mostly be seeing the adults, getting jiggy. A lot of them will overwinter as eggs or larvae, then this is the stage where they come out, consume as much nectar as possible and get together. We’ve already seen quite a few ‘couples’ this morning. It’s quite interesting to watch, as their genitalia rotate — some by a full 360 degrees. Some just rotate by 180 degrees. Often it is the male that you see, being dragged around the garden. There’s lots of mating going on, hence why there’s lots of pollinating going on because nectar is a really good fuel source. They’re feeding themselves up for mating or taking the food back to their grubs – in the case of bees.

What sort of numbers are we talking about?

We have about 24,000 species of insect in the UK. 700o species of fly alone… so there are more species of fly in the UK than there are mammals on the planet. Just to put it in context. There are about 7500 species of wasp, 7000 flies, 4000 beetles, 3000 butterflies & moths.

Is there still too much focus on bees rather than insects in general?

We’re enjoying a cup of tea thanks to the plant being pollinated by a fly. We’re very species biased – we like a little fluffy bee. We like a slightly pointless butterfly but the hard working fly, even your house fly, are really good pollinators. The house fly, along with mosquitoes, are some of our most important pollinators. And yet both of them we hate. That’s why we’ve really got to start educating the public and saying: ‘Look, we’ve got to take our own feelings out of the equation and start to learn more about the environment.’ Wasps are brilliant, I love wasps. In autumn, the females – the worker wasps – get thrown out as the queen doesn’t need them any more — so they become jobless and homeless overnight. Then in the autumn we have lots of rotten fruit, which makes alcohol, which makes this homeless, jobless, drunken female fly round the garden – and we wonder why she’s aggressive?! Wasps eat aphids, they eat everything, they’re great predators. Don’t go killing them. 

Why do some people get bitten more than others, by mosquitos? And do you have any tips on how to repel them?

Number one is genetics – you may be more tasty. They have co-evolved alongside us for millions of years, so they have learnt all the cues for tastiness. So, when kids get munched, they can blame it on their parents. It’s nice to know you can blame them for absolutely everything. Your blood groups – I am a ‘b’ so I am less common than you lot, so they would have less time to have got to know my smell, from an evolutionary point of view. Being slightly bald makes you more reflective – a bald man rowing across a lake, would be an amazing lure! Being pregnant, or a male drinking ale. Hang around with someone who is more attractive, that is my general advice. And using repellent? A lot of our repellents attract them and then dissolve their feet –  which is a really horrible way of killing things. I don’t like that. I don’t use deet or anything like that. It’s horrible stuff – it’s toxic over long periods of time, and toxic to aquatic environments, so when it washes off your skin, it poisons the environment. When we do tropical field work we take all deet products off our kit. We just dress appropriately. You know those films where they have females dressed in tiny shorts and little skimpy tops. No way! I have long trousers, a stupid over-shirt, leech socks on (I don’t want leeches going up there.) Tight-woven clothing is best – they’ll just go straight through cotton t-shirts and leggings. Loose-fitting but tight weave. The London School of Hygiene and Tropical Medicine are trying to develop a fabric that’s impregnated with a natural repellent.

Who are the unsung heroes of the insect world?

There are migratory hover flies — we are just starting to look into how far they migrate, using radar and all sorts of interesting technology, to scan them as they come over. What they are able to do, as they are so high up, is see ‘relic plant populations’ – isolated plant communities which have been cut off. These hover flies spot these clusters, they’re not specialist in their food choice, their generalist, so they just go and munch them and spread all this pollen. So, they are are bucking the trend of declining insects as they are able to eat a variety of food sources and survive in adverse conditions. They’re helping to spread the pollen of threatened species of plant too, spreading their genes, then they come here, mate with our hover flies and spread their own genes further… and their larva are aphidaphagus – they eat aphids – so great biological control. Hover flies are some of the top pollinators, their larvae eat aphids and other pests. Lots of insects have larvae which are decomposers – they are nutrient recyclers. However, hover flies, like all insects are being massively impacted – the number one cause is land-use change, insecticides and climate change.

What is the point of midges?

Chocolate. Your biting midge – ‘the Scottish scourge’ – things like that are massive pollinators. Only the females are blood-suckers. There are about 23 species of midge that pollinate cocoa. The cocoa plant is a bit like a panda… really rubbish at naturally reproducing. It has about a 30% success rate in the wild so, you put it in a cultivated system and it goes down to about 5%. This little midge is the only thing small enough to get through to the ovaries at the bottom of the cocoa flower. So, if you get rid of midges, you get rid of chocolate. The whole problem with cocoa plantations is that they got rid of a load of surrounding plants, and just planted cocoa plants and in doing so, they got rid of the habitat of these midges. The midges need trees, as adults, and the need the detritus from the trees to accommodate their larvae. Have they learnt from this? Yes, they are going back to agro-forest systems which is really nice. They are putting cocoa plantations in woods. It’s great as a small-scale economy as well – giving back cocoa-growing to the local population, so it’s better all round.

The difference between poisonous and venomous?

Both involve toxins – but one is ingested and one is injected. You’d be bitten by a snake or stung by a wasp – and that is injecting venom into you. This could paralyse you or be necrotic, so can dissolve your flesh from the inside, eg. recluse spiders. We have loads of neglected venomics groups, ie venomous insects. Now we are looking at insects that we didn’t think were venomous when in fact there are so many flies that are venomous. Anything that’s a predator is going to have bit of venom. For example, robber flies, across the species have 10 different kinds of venom. One has been found to kill humming birds… they are that amazing as predators. This is really interesting for us, for many reasons. The idea of novel venoms in medicine, is a very good thing because they have such a quick neurological effect that we think ‘this has got to be useful somehow’.

Dispelling the myth

There’s this myth that crane flies / daddy long legs / harvestmen are the most venomous creature on the planet if only they had mouth parts to pierce our skin. Claxon alert!!! There are three things we call a harvestman. The harvestman spider – they’re not spiders, they are ‘opiliones’. They are not venomous. They are arachnoids but they are not a true spider. Crane flies – most don’t feed as adults and even if they did it would be nectar as they are all vegetarians. The only things that are venomous are the true daddy-long-legs spiders that hang around your house. All spiders are venomous – they have to kill flies and other things though there is one spider that’s a vegetarian. Most of them dry-bite humans anyway – they use their venom to paralyse their prey they don’t want to waste it on us.

What is the weirdest thing that anyone’s sent you in the post?

Crane fly larvae from the backside of a police dog. They were worried about the welfare of their dog and the vet would treat them most of the time but on this occasion was a bit confused and wondered if the larvae was dangerous. So, they sent it to me for verification… the dog was fine but it had pooped out this crane fly larvae. So, I looked at it, decided there was no way it could have travelled though the dog’s entire digestive tract without it dissolving so I surmised that it must have been sucked up the dog’s bottom somehow.

Tell us the story of the maggots in the suitcase…

We have been involved in forensic entomology for a long time. One of the first recorded cases was about 1000 years ago, by a Chinese magistrate who was knew about maggots and flies being attracted to blood. One of the villagers bludgeoned another villager with his machete, then cleaned his machete. It was a very hot day and all the other villagers came out and said ‘magistrate, magistrate — find out who is the murderer’. So, he got all of the villagers to bring out their machetes and lay them out in front of them and, within about 10 minutes, a load of flies turned up on one machete. And he was like: ‘there’s your killer’.

The police came to us, as a corpse had been found in a suit case, and they asked if we could tell them when the maggots got in there. Was it after they opened the suitcase or before? So, they cut a load of different zips off suitcases to see if, of all these different flies, their larvae were able to get through the zips. They filmed it, and it didn’t matter how posh the suitcase, they were able to stick their ovipositor – their egg-laying tube – through the zip. Or the larvae just squeezed themselves through. So, at that point, all time frames are gone… So, they were able to look at the guy’s alibi and know that it didn’t stand up. So, it was a really helpful bit of evidence they used to prosecute him.

And bees used for finding narcotics?

There are such things as sniffer bees. Honey bees have a tongue and stick it out to get nectar. It will stick out its tongue based on pheromone cues. So, what we did was trained them – we put them in little capsules and leave their heads out. Then we would flood the air with nectar – but you would lace it with whatever chemical you wanted to trace. So, it’s basically like Pavlov’s dog. It takes 5 minutes to train a bee so, in a normal environment when they smell the chemical, that makes them think, ‘Ooh, nectar, and they stick their tongue out’. You know those car vacuum cleaners – imagine one of those and it’s got a load of bees in capsules in it and they have a light beam projected across the front of the capsules – and when enough bees have stuck their tongues out, it breaks the light beam and an alarm is triggered. You can use it in airports. 24 hours later, the bees get released having done their job. They have used them to locate land mines too.

Thank you Dr McAlister!

We are running a competition, via Instagram, to win a copy of Dr Erica McAlister’s latest book: The inside out of flies Follow us on Instagram for your chance to win. You might even get one of our signed copies

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