ID : Gall Wasp species

Andrew C · #1 (**permalink**) 08-03-2011, 07:25 AM

Good morning,

During a moss oriented walk on Saturday (05/03/2011) at Holyford Woods near Seaton in Devon (UK), I came across two flies.

One has been identified as Yellow Dung-fly (Scathophaga stercoraria) but I wanted to ask about the second which I suspect to be a Gall Wasp species, Neuroterus quercusbaccarum emerging early to lay eggs as in the description within Chinery's Domino guide to insects.

Is this a sound conclusion?

Many regards,
Andrew.

poschiavanus · #2 (**permalink**) 08-03-2011, 12:25 PM

I think this probably is a Cynipid: it has less than 18 antennal segments and enough long veins, but although I have a few specimens I'm yet familiar with the jizz of the family.

Following Robin Williams Oak Galls in Britain (p. A-74) I don't think it's Neuroterus quercusbaccarum. In his description both males and females of the sexual generation are described as having the thorax dark neutral brown, straw-coloured tegulae and no notaulices. I also suspect that the ratio of wing/body length is greater than 130% which is the figure he gives for both sexes.

There are plenty of other gall wasps with recorded flight periods starting by now. Most keys require sexing of the insect to get anywhere, and this one is waggling its antennae too enthusiastically for this.

Andrew C · #3 (**permalink**) 08-03-2011, 03:33 PM

Afternoon,

Thank you for taking the time to advise me on this. It is a pity it can not be determined to species level. The specimen was quite lively and would not sit still for more than a split second and I was not that keen on taking it home without the use of a microscope or a key in my possession yet. Plenty more Gall Wasps in the woods.

Thanks,
Andrew.