I bet you didn’t know that 2019 has been designated The Year of the Fly, did you? It’s true. And now I expect you want to know why. Why have a year of the fly? Flies are nasty, dirty little nuisances and you can think of a lot of better things to have a year dedicated to, am I right?
Well, I have news for you. Many, many species of fly are neither nasty nor dirty and on the contrary are very useful to us. They dispose of excrement and dead bodies, they pollinate our crops and our flowers, they keep down the numbers of insect pests like aphids, they keep our soil healthy, and not least, they provide food for our garden birds and other animals.
Flies can also be both colourful and clean1. There are a huge variety of flies, around 7,000 species2 right here in the UK, ranging from the tiniest of fungus gnats to the smacking great hornet-mimic hoverflies. Bee-flies are particularly cute and fluffy, and many hoverflies and soldierflies are strikingly beautiful, but all flies are miniature marvels of nature, perfectly adapted to their lifestyles. Even Bluebottles, Greenbottles and other blowflies are amazing little things, seen in close-up. You would be surprised if I tried to describe the detail, so I shall have to just show you – and when I do, you will also be amazed at how intricate they are, and how delicate.
So there are pollinating flies, parasitic flies, blood-sucking flies, flies which feed on decaying organic matter, flies which dispose of dead things, and flies which feed on other insects. Some species have larvae which feed on one thing (e.g. other insects) and adults which feed on something entirely different (e.g. nectar). Some adult flies don’t feed at all, but simply live very short lives until the fat reserves they built up as larvae run out. By the way, we may be used to thinking of flies as the adult flying insects which we are all so familiar with, but for the majority, the larval stage is the longest and it could be argued, the most important. The function of many adult flies is simply to mate and die, although some will overwinter and live to fly another spring and summer. None of them can chew. All of them are liquid feeders, though some have developed some fairly vicious cutting or piercing equipment for getting at the liquid that they need.
In recent years, I’ve become very interested in flies in general, and hoverflies in particular, and this year – The Year of the Fly – I’m going to try to give you a good number of posts here on The Sparking Synapse to show you why they are so fascinating, and to share some information with you which I bet most of you did not know. Since I am a hoverfly person, I’ll start with an overview of that genus, the Syrphidae, and before I start I’d better tell you that most flies do not have a common name, but don’t worry. Some of them do, and anyway, there won’t be a test at the end of the year!
1 – Well, as clean as anything which lives outdoors and has no truck with modern plumbing
2 – You’ll see different estimates of the number of species in the UK, depending on where you look, but my figure comes from the UK special interest group The Dipterists Forum