Wasp 0.5mm primitive?

JRsbugs · #1 (**permalink**) 28-09-2009, 12:26 AM

Hi,

Taken on 27th September 2009. It looked like a speck of dirt, with my interest in all things tiny I checked it out with my macro lens and teleconverter. It wasn't close enough to get better magnification as it was on a waterlily leaf. The wings are unusual and I would think primitive, with diagonal veins and many long hairs on the edges.

It may have been less then 0.5mm in length, but certainly wasn't more. I haven't seen anything like it before, I doubt at that size many have! Any clues appreciated, I haven't started looking yet but as it's so unusual I'm not confident of finding it.

Janet

Wild-Woman · #2 (**permalink**) 28-09-2009, 04:14 AM

Maybe one of the gall causers?

Rossco · #3 (**permalink**) 28-09-2009, 10:45 AM

That is tiny. It's a chalcid of some sort and it's certainly small enough to be one of the egg parasitoids. It would be practically impossible to identify this to species from a photograph, but I can narrow it down a little by saying it's not one of the trichogrammatids, as it's got a metallic lustre.

JRsbugs · #4 (**permalink**) 28-09-2009, 11:30 AM

Thanks both for the suggestions, the face does look like a Chalcid but the wings are very unusual. I have had some about 1mm long with very basic wings, but this has long hairs along the wing edges which I haven't seen before. They also have dark edges and what looks like diagonal stripes, but that might be the hairs overlapping the wings!

You can enlarge the pics a little more by clicking on them, it might give a slightly better view.

JRsbugs · #5 (**permalink**) 28-09-2009, 11:34 AM

I looked up Trichogrammatidae, they do have hairs on the wings and I would say they are paddle shaped:

Quote:

Their forewings are typically somewhat stubby and paddle-shaped, with a long fringe of hinged setae around the outer margin to increase the surface area during the downstroke

Trichogrammatidae - Wikipedia, the free encyclopedia

Any ideas what else has this type of wing?

JRsbugs · #6 (**permalink**) 28-09-2009, 11:37 AM

The Universal Chalcidoidea Database on NHM might give a clue, the diagrams show wings much the same.

Chalcidoidea

JRsbugs · #7 (**permalink**) 28-09-2009, 11:46 AM

There is an explanation of the differences of two wasps, Aphytis and Trichogramma genus. Aphytis is host specific, there's the Waterlily aphid on the leaves, Rhopalosiphum nymphaeae which are on average about 1mm long, some smaller with an occasional one bigger.

Family TRICHOGRAMMATIDAE

JRsbugs · #8 (**permalink**) 28-09-2009, 12:06 PM

It just occurred to me that wasps in Trichogrammatidae are stricly egg parasites. That would rule out the aphids as hosts as they have live young.

I do have a very small Dolichopid fly which at the moment are mating, again! Yesterday they were at it, one female was very heavily laden with eggs and after being mated with, which they seem to do several times, she spent some time stood in one place, having a trail with a black blob trailing from her tail end after mating. I was waiting for her to lay eggs, but after going away and returning she was dead. It was after this I saw this tiny wasp!

I took pics of the Dolichopid, they are around 2mm long with the male a little smaller, the gravid female maybe a little longer. When I fixed the pics I saw she had a hole below her ovipositor with a few eggs showing, there was a worm in the water near her!

So, it may be the wasp was intending on laying in the Dolichopids eggs!

JRsbugs · #9 (**permalink**) 28-09-2009, 12:15 PM

Oh wow, some interesting stuff! From the link above on Trichogrammatidae, in the 'BIOLOGY' section it states:

Quote:

This family also contains some of the few truly aquatic species of Hymenoptera known. Several species in several genera parasitize eggs of Odonata, Dytiscidae, and other aquatic Heteroptera. Propulsion underwater may be by swimming with the legs or with the wings depending upon the species. As many as 70 individuals may emerge from a single dytiscid egg.

I have Dragonfly eggs, and Dytiscidae apart from many other things in and around the pond!

JRsbugs · #10 (**permalink**) 28-09-2009, 12:31 PM

I think I can rule out any genus in Trichogrammatidae, as mentioned in distinguishing characteristics:

Quote:

The antenna contains 2 or less funicle segments (i.e. antenna appearing 5-segmented or less with the club counted as one). Quite often the wing setae are arranged in rows.

I can see mine has more than two segments between the club and the 'stem and joint' on the head end!