Thursday, 27 February 2014

Cut and run

While continuing to sort my malaise trap-trawl, I've found another blast from my past Zoology lectures... Cleg flies or Horseflies.

Microscope close-up of a Cleg Fly head (x5)

I'm seemingly better at recalling the darker, gruesome side of zoology. I also got to know these insects rather intimately while working in damp Sussex woodland gardens; prime Deer, Human and Cleg habitat. These stealthy, bitey beasties are blood feeders and for them, pretty much any large mammal will do.

Palp and the sponging labella (x10), protecting the nasty
 pointy bits which can just be made out in silhouette 

Only the females partake in blood meals as they need the nourishment to produce their eggs (the males are nectar feeders). The mandibles and maxillae (mouth parts) of the female are brilliantly adapted into pointy, hardened, stabbing structures. These are shoved through the skin and then rapidly scissor back and forth like the blades of a tiny, hellish hedgetrimmer. The fly then injects an anti-coagulant and sucks up your life's fluid.
The stunning psychedelic banding of the eyes fades after death but can still show up in good light

This less-than-subtle eating habit apparently works just fine for them; the theory being the pain-inflicted victim will be more concerned with assessing the wound than swatting the culprit. However, I am a vengeful being and I recall the book The Wasp Factory graphically documents some pretty inventive ways to dispatch insects...

A live Notch-horned Cleg I caught last summer. 
After freezing to photograph it some more, the colours faded.

In all seriousness, I only dispatch the ones I need to photograph and identify (and perhaps a few others for self-protection). Going by the brownish colour of the wings and the dented antennal segment, the above species is the Notch-horned Cleg, Haematopota pluvialis. Even if they do make my skin crawl (or run about flapping my arms), these little.... ahem, guys are awesome-looking and resilient; when one lands and you give it a full-on whack, even if your aim is only slightly off, it casually flies off unscathed. But beware, for it has not likely to have gone far...

Chrysops relictus - Twin-lobed deerfly. Distinguishable from a similar species C. caecutiens by the reddish tibia (leg segments) and the black chevrons on the abdomen

All Deerflies, Clegs and Horseflies belong to the family Tabanidae and in the UK we have about 30 species. Another type I regularly come across is the Twin-lobed Deerfly. These are agile and difficult to catch, but just last summer I rescued the botanist Giles and our volunteer Georgina from certain doom by potting one on Giles' head. 

This one also died by freezing; it got off lightly.

To be honest, I don't really have time for a Wasp Factory, plus freezing is much less messy.