What do you think of when you hear the word fly? Possibly a bluebottle buzzing around your house on a hot day, relentlessly bouncing against the window no matter how wide you open it. Maybe a hoverfly sunbathing on a leaf, or a cranefly trailing its long legs as it skims over the lawn. 

There are more than 7,000 species of fly in the UK, from the familiar houseflies to a catkin fly found only in the Highlands of Scotland. You can spot them in gardens, woodlands, meadows and just about anywhere else you care to look. They are incredibly diverse, often beautifully patterned and take on a wide variety of extremely important roles. They are recyclers, clearing the countryside of rotting plants, animals and dung; they are predators, helping balance the populations of other insects; and they are pollinators, aiding the fertilisation of flowers. Flies are amazing!

Let’s take a closer look at five fantastic flies…

Semaphore fly (Poecilobothrus nobilitatus) 

Male semaphore flies really know how to put on a show. It starts with having the right look: a shining, metallic green body and dark, white-tipped wings. Next, they need to find the right location. They gather around puddles and pools with muddy margins. Finally, it’s time to show off their moves. A male picks out a female (whose wings lack the white tips) and begins to dance. He flicks his wings, flashing those white-tips, then takes flight and flips over her in a high-speed arc. Who wouldn’t be impressed by that? 

Common awl robberfly (Neoitamus cyanurus)

Robberflies are the fighter jets of the fly world. They are powerfully built predators, darting out to pounce on prey with their piercing mouthparts. There are 29 species in the UK, including the common awl robberfly. This is a large, slender fly with black and orange legs. It hangs around in woodlands, hunting beetles and other insects. You’re most likely to spot one resting on a log or low-growing plant. The common awl robberfly can be found across the UK but is more common in southern Britain. 
 

Ferruginous beegrabber (Sicus ferrugineus)

Now this is a fly with an intriguing name! Ferruginous just means rust coloured, which makes sense when you see this hunched, reddish-brown species. But what about the ‘beegrabber’ part? Females loiter around flowers, waiting to ambush an unsuspecting bumblebee. They grab their target (sometimes in mid-air!) and inject an egg into its abdomen. The fly larva feeds on the inside of the bee, eventually killing it and pupating inside the dead husk. This makes it a parasitoid – unlike a parasite, it routinely kills its host. You can find ferruginous beegrabbers in grassy places across the UK, including gardens.  
 

Bat-winged phasia (Phasia hemiptera)

This is another parasitoid, but it relies on shieldbugs as its host. It’s known to target green and red-legged shieldbugs. Males are spectacular flies, with a flattened, orange-red and purplish-black body. Their broad, strangely curved wings bear beautiful iridescent patches that shimmer in the sunlight. Females are smaller and lack the colourful patches on the wings. You can often find bat-winged phasias visiting umbellifers and other flowers in wooded areas. 
 

Orange-sided comb-horn (Ctenophora pectinicornis) 

Most people have seen a cranefly, though many would call them a daddy longlegs. They’re the familiar brown, gangly flies that seem determined to enter houses in late summer. But there are more than 330 species of cranefly in the UK and not all of them are brown! Many have intricately patterned wings, whilst some are spectacularly colourful. The orange-sided comb-horn is definitely in the spectacular category. These craneflies live around old broadleaved trees, where their young depend on rotting wood. Males can be recognised by their large, feathery antennae – the source of the name ‘comb-horn’. 
 

This is just a glimpse into the fantastic world of flies. There are thousands more to discover, many right on our doorsteps. This summer, why not see how many different flies you can spot? You might just discover a new obsession!