Thread subject: Diptera.info :: Tabanus autumnalis?

Posted by empeejay on 14-06-2006 13:09
#1

Is this a male Tabanus autumnalis?
Taken at Potter Heigham, Norfolk, England on 20 July 2000. Body length 18.5mm.
I've also attached a picture of what looks like a normal autumnalis from Somerton, Norfolk on 15 July 1985. Body length 16mm.

Posted by empeejay on 14-06-2006 13:16
#2

Not sure what happened to the picture. This should be the upperside.

Posted by empeejay on 14-06-2006 13:17
#3

Underside.

Posted by empeejay on 14-06-2006 13:18
#4

What I assume to be a true autumnalis male upperside.

Posted by Zeegers on 16-06-2006 08:07
#5

You are right.
Both are autumnalis, the 'true' one is typical, the other one unusually dark. It fooled me as well on first sight. T. autumnalis is quite variable, though. In the middle east they turn completely orange, for example.


Theo Zeegers

Posted by Susan R Walter on 16-06-2006 12:43
#6

I found a very large male of this species sheltering under the external frame of my kitchen window in Essex on 14 June 2006. Very dark, with very pale markings, 25mm. We overlook a 900 acre marsh, so ideal countryside for them. He was quite lively and had to be restrained with clear plastic food wrap to be photographed, which unfortunately has softened the focus. I got very excited initially because I thought he was Hybomitra, but T autumnalis is not bad - only recorded in about 50 10km squares in the whole of the UK (quite a lot of the records are from the Thames Estuary, which is where I live).

I think the black stripe down the middle of the sternites is diagnostic for autumnalis isn't it, so even when the dorsal pattern is variable, you can pin it down to autumnalis by the ventral stripe?

Edited by Susan R Walter on 16-06-2006 12:45

Posted by Zeegers on 16-06-2006 15:37
#7

Hi Susan


the dark ventral vitta is characteristic in the UK only.
On the mainland there are many more species with this feature, for instance bovinus.
But in UK OK !

Theo