miked's picture

Miked's 180th spot submitted on 28th June 2009

Observed: 28th June 2009 By: miked
iSpot team
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 MG 0508
 MG 0499
Description:

A horse fly I suspect, one had a slightly deformed wing so was easier to photograph. Again seemed to be attracted to blue car, there were about 20 all round our car and in it as soon as the doors were opened. Second image shows one of the flies in the car.

Identifications
Species interactions

No interactions present.

Comments

the naturalist man's picture

Horse fly

The pattern of pale triangles down the centre of the abdomen and pale patterning on the side of the abdomen indicate it is most likely Tabanus bovinus - I don't know an english name.

I once worked on a nature reserve where we played a rather stupid game, we did not knock a horse fly off ourselves until we had identified it. You quickly learnt your horse flies!

One other posibility is Tabanus sudeticus. From my experience though it usually has less distinct patterning on the side of the abdomen. T. sudeticus is also larger. Would you say the horse fly was longer than 20mm? If it was much over this then it may have been T. sudeticus.

Graham Banwell

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Martin Harvey's picture

Tabanus, but which?

Horseflies can be tricky to ID, and knowing the size would be helpful here. I wonder whether this is Tabanus bromius, the commonest species in the Chilterns and smaller than the ones that Graham has suggested. The photos show a male (eyes meet above head) and a female (eyes not meeting above head) - nothing to fear from the male, it's the females that crave blood!

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Entomologist and biological recorder

the naturalist man's picture

Horsefly

Hello Martin

I had ruled out T. bromius because of the size. At around 1cm I did not think you could get such a good picture, though I guess with modern camaras anything is possible. Also I always think of them as being very dark and more uniformally coloured but again with flash perhaps the patterning could be picked out.

I had not noticed, however, the single band in the eye of the first picture, given what I just said about camaras I think you are correct.

Can you remove an identification?

Graham Banwell

Visit the iSpot Yorkshire forum for information on events, issues and news relating to 'God's own country'
http://www.ispot.org.uk/forum/8411

miked's picture

Looking at the pattern on the

Looking at the pattern on the background that the fly was sitting on (i.e. car door) and taking another photo of this including a ruler suggests that the fly is over 20mm and from memory the flies were big, perhaps not as huge as the biggest horseflies but still much bigger than cleg.
The horseflies at the warburg reserve have very likely been ID'd as they are seen in such large numbers in the carpark and there is such a comprehensive list of most biodiversity at the reserve.