First New Fly of the Year

And it's not what any of us expected, especially me!

Yes it looks like a well-rotten cucumber, I agree. But this is a lifer for me! 

So you may recall that I signed up to the UK Hoverflies Larval Group on Facebook just a couple of weeks back. Well I was obviously paying attention somewhere along the line, because as soon as I found this beast glued to the underside of the boulder I'd just heaved out of the ground, I knew it was different to the usual Syrphus larvae I find in leaf litter. It seemed more wavy-edged along the margins, the colour was richer and the mottling more pronounced. But mostly, just cop a look at those rear breathing tubes! 

Cor, just look at the length of those! 

The rear breathing tubes on Syrphus are broader than they are long, these are clearly longer than broad. So, definitely not a Syrphus but what is it?

It's really quite an attractive thing, in an admittedly rather strange kind of way.

I felt that it looked good for Epistrophe, so put these three images up on the FB group. Not too much longer and it was confirmed by Nicola Garnham, one of the page admins, who said it was probably Epistrophe grossulariae but should be reared through to be certain. 

There are five species of Epistrophe in Britain, all of which occur in the southern half of England (plus one species known only from a single 'somewhat doubtful' Welsh sighting). Of these five, only two penetrate into the Scottish Highlands. One is Epistrophe eligans and the other is Epistrophe grossulariae. Happily, eligans has particularly elongated rear breathing tubes, which this larva lacks, leaving grossulariae as last man standing. All of this means that I've just ticked a hoverfly from the larval stage - I'm pretty sure I've never done that before! 

As larvae they live up in the trees feasting on aphids, particularly those found on Sycamore. The fact that I found this larva beneath a clump of Sycamore and Norway Maple makes perfect sense. They come to earth with the falling leaves, munching on any aphids that have also fallen to earth, before effectively running out of food and spending the winter in a state of dormancy. Then they pupate and emerge as adult hoverflies from April onwards (or probably June onwards up here).   

I'm also pretty sure that I ought to have seen this fly already, in the adult stage I mean. It's quite common across Britain, so is an overdue addition. I shall be keeping an eye out for the adults this summertime, I expect to be stalking and swiping at hoverflies for much of the coming season.