Thread subject: Diptera.info :: Tabanus spodopterus? Or T. eggeri?

Posted by Sundew on 11-07-2022 15:44
#1

Hi,
Here comes a continuation of the thread https://diptera.i..._id=102998.
In these days I often visit a wood path with deep, water-filled ruts where lots of insects come to drink. About 10 big Tabanus females are circling with a loud buzz over the water and dip their abdomen tips in again and again. Are they laying eggs? Their abdomens appear dark red. Males are also present.
Now and then a fly rests for drinking. So I had the chance to take some pictures. I think they belong to the same species with black antennae as in the above mentioned thread. To get a picture of the belly is hardly possible...
The location is identical (southwest Germany, west of Stuttgart).
Maybe, we come closer to a species ID now. With Theo's key https://waarnemin...S_2019.pdf T. spodopterus was the best choice.
I am looking forward to opinions! Sundew

Here are the females.

Edited by Sundew on 11-07-2022 22:01

Posted by Sundew on 11-07-2022 15:44
#2

More females.

Posted by Sundew on 11-07-2022 15:45
#3

A male.

Posted by Sundew on 11-07-2022 15:45
#4

Male head.

Posted by Sundew on 11-07-2022 21:59
#5

I happend to kill a male. Intended was a gentle knockout blow, but the fly didn't survive. At least photographing the belly was now easy. The colouration points to Tabanus eggeri. This species should show a little bit of red on the antenna, but there isn't. "First hind edge cell strongly narrowing towards the wing edge, often even closed and stalked" is also not very obvious. Also the size of the yellow tergite markings is smaller than shown for T. eggeri in Theo's key. The females, however, seem to have bigger yellow triangles. - So what character is decisive? Experts to the front!

This is the belly.

Posted by Sundew on 11-07-2022 22:00
#6

And this is the back of the same specimen.

Posted by Zeegers on 11-07-2022 22:49
#7

I have hardly any doubt this is indeed spodopterus.
Total black antenna and grey palpus are distinctive.
The dark band on vitta is too dark for eggeri, you might have lighten it by flashing.
Shape of central tergites is distinctive.

Eggeri has partly orange antenne and tapering posterior marginal cell, as mentioned..
Nice work, congratulations !

Spodopterus is marching north and has recently reached Belgium.


Theo

Posted by Sundew on 12-07-2022 02:44
#8

So we stay with T. spodopterus, as the middle part of the sternites is slightly darker. Very well! The species is known for the Berlin/Brandenburg region from the first half of the 20th century. From what was it concluded that it was now extinct in Germany? Maybe it was just overlooked.

Edited by Sundew on 12-07-2022 02:51