April 2024

Flies!

Well, we've done wasps and spiders, so it's time for that other little critter that doesn't rank highly in the popularity stakes. In fact mention of them often prompts an expletive in the form of 'YUCK, they're disgusting'. I'm talking flies. There are apparently 120,000 known species of flies on the planet, of which we have about 7,000 here in the UK.

If you go online for information about flies, you'll get no end of pest control companies who'll happily advise you on how to get rid of those infernal house flies, fruit flies and any many others. But don't be too quick to reach for the fly swat because we actually have a lot to be thankful for, from this diverse group of insects

Flies are said to be only second to bees when it comes to being effective pollinators, and they feed on rotting organic matter, both animal and vegetable. Their larvae (more commonly known as maggots) are particularly effective detritivores. As Dr Erica McAlister, fly enthusiast from the Natural History Museum says 'without [them] and other decomposers, we'd be up to our eyeballs in poo and dead bodies'..........not a desirable state of affairs!

Flies belong to the Order Diptera, which comes from the Greek for "two wings". Many other insects such as bees have 4 wings, but in flies the hind wings have become modified sensory organs (called halteres) which help to control their flight

Flies come in many different forms, and can mimic other insects such as wasps and bees. Below are 4 types of fly spotted in and around the Rec this April, giving a brief idea as to the diversity of this amazing, if unloved, group of insects.

The first is the Dark edged bee fly, above. This small fly looks for all the world like a tiny bee. It uses this mimicry to get close to the nests of solitary bees, where it scatters its eggs, which as larvae, go on to parasitise the bee larvae.

The dark leading edge to the wings give the fly its name, and other distinctive features are the long tongue (or proboscis) and skittish flight, with episodes of hovering. It can be seen in the Rec garden currently.

This second is the autumn housefly or face fly, so named because it feeds on secretions around the eyes, mouth and nostrils of cattle and horses. This is to their considerable irritation and sometimes harm, in the form of serious eye conditions. It is closely related to the common housefly. Definitely not good on the PR front! These were basking in the Valley Gardens at the Uni earlier this month.

Below is the Hawthorn fly, otherwise known as the St Marks fly, because the adults usually emerge around St Mark’s Day, 25th April. It has a long, black shiny body, and its legs dangle beneath it as it sluggishly flies around. These are amongst the good guys, the adults being important early pollinators They often fly around wetlands and these were photographed in the Valley Gardens at the University. Unfortunately one got a bit too close to the water!!

Lastly below is the Cranefly, probably the Picture-winged cranefly. It can be identified by the banded legs, brown striped abdomen and distinctive patterns on its wings. They generally inhabit well wooded areas, but this one chose to visit Holyrood Ave, just around the corner from the Rec.

How to find Valley Gardens on Highfield Campus?  Starting in University Road, immediately past the Jubilee Sports Hall, turn down the sloping service road. At the far end, go down the steps to the left, alongside the old sports hall.  Once you're on the flat again, bear right, and then left once more, crossing the waterway to come to the entrance arch.  The gates to the Gardens are generally open from 8am onwards on weekdays in term time, and sometimes on other days.

Words and photos: Denise Long