Keep ’em peeled for mean hornet robber fly

8:31am Thursday 20th September 2007

Wet followed by warm weather is just what many flies need to prosper and as a result we have seen a real increase in the numbers of many fly species.

Early in August it was mosquitoes. They were followed by horse flies and now it seems to be the turn of the real fly generalists we call houseflies.

Whilst we certainly are finding this boom in fly population a nuisance, if not a menace, many species that specialise on feeding on flies are prospering immensely.

Robber flies are flies themselves but they specialise in feeding on other fly species.

There are just over 30 different robber fly species, some of which are small and go more or less unnoticed to most of us who are not actively searching for them.

Others are rather fearsome looking with large, thick muscular legs covered in bristles which they use to capture other flies whilst in flight.

Robber flies like to rest on a perch and wait for a fly to pass by before dashing into the air to catch its luckless victims.

These pursuits are usually over in a matter of seconds and the hapless fly is usually consumed in flight.

Sometimes, in the quest for a good vantage point to hunt, the robber fly will hitch a ride on us.

Their large and bristly appearance can sometimes cause alarm and can easily lead us into taking too hasty an action to rid ourselves of them.

It is, however, well worth the effort to stay your hand and happily wear one of these most unattractive insects as a badge for as long as it is happy to remain on you, as their presence is a deterrent for other flies from harassing you.

If another one is stupid enough to press home its assault, the robber fly will launch itself into action and attempt to consume the assailant.

It is almost like having your very own fighter squadron ready to scramble to your defence should an enemy fly have enough affront to invade your personal airspace.

One species of robber fly which has been found in Kidderminster is recognised as an international rarity.

I have yet to see one, but I do keep looking out.

This beastie is Britain's largest robber fly and is extremely distinctive, having a yellow end to its abdomen which superficially makes it look like a wasp or more probably due to its size a hornet. This has earned it the name of the hornet robber fly.

The hornet robber fly certainly looks fearsome but it lacks any form of sting and it's good to know that an animal of this size poses no threat to us but quite the reverse, as it devotes its life to consuming flies, some of which will certainly be out to do harm.

If you strongly suspect you have come across one of the beasties the Wyre Forest District Council Ranger Service would love to know.

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