New Microscope: Psyllid dissection!

[Jason Green]

Hi all,

Following on from my post on microscopes, my Apex Examiner stereo-microscope featuring overhead LED illumination with a 2x objective lens (?) and WF10x eyepieces arrived. Pretty impressive it is too! No CA since all optics are corrected glass.

I found a psyllid outside today, dead on an unused spider's web. Looking at it against the wooden shed I thought this tiny thing had been dead for weeks and half degraded already.Anyway, I chucked it on the specimen plate and switched on the LED. Surprisingly it was still firm and well coloured, so maybe not as long-dead as I thought. I plan on making it into a species slide, and so I have chosen to retain a wing, a leg and an antenna. Would anyone else choose anything different? All work was obviously done under the 20x lenses with the LED.

Dorsal thorax
Any idea on species?


Lateral
About 4mm long


Wing
About 10 mins to remove!

The wing removal was pretty difficult all told. First off, there's a fair amount of tension between the top-edge of the wings. When I inserted a tool, the wings still tried to hold together like a paperclip - I could actually lift it up like it! When I finally managed to get the tool to the inside between the wing and abdomen, it was still held fast, certainly more difficult to separate than a barkfly. Overall the body is much stronger than you'd expect - you can push the whole body backwards by pressing the antenna without it bending. This has given me a whole new respect for the strength of these insects that are so often thought of as delicate.

Unfortunately the photos aren't the best as I'm having trouble getting my prosumer to focus through the eyepiece. Apparently cameras with fewer internal lenses work best. Any ideas?

Thanks for reading!

Take care,

Jason

[ChrisR]

Dead insects can be incredibly rigid and and the same time delicate ... it's very easy to trash everything trying to manipulate one bit into view. The usual procedure is to 'relax' the dry insect - to put it into a humid environment (plastic box with wet tissue paper) and allow the muscles and tissues to soak up the water and become floppy again. When it is properly relaxed it makes a big difference and dissections are much easier It also helps to have a couple of pairs of really fine forceps - I like to have 1 straight and another curved. They cost a bit though - about 15-20 quid each - available at entomological exhibitions

Still, nice wing photo Just get some of that stacking software and let it merge 8 or so photos together and you'll have a superb image

[Jason Green]

Thanks Chris. I could do with as many tips as possible!

[RobSutton]

A long time ago I did some research on Psyllids and from memory the extra bits you need to look at are the genal cones (two sticky out bits between the eyes at the front end) and the genitalia - I've just googled Psyllid Identifcation and there's a good breakdown of what bits are called what here:

psyllid morphology

[Acutipuerilis]

Excellent work there, Jason!

For the pysllids, you've picked some useful bits to take with you (antenna, hind leg and forewing are all good), but most of the IDs depend on genitalia. In the case of females you've got it easy - most of the IDs can be done with a side view of the terminal segment down a microscope. The problem is, a lot are ambiguous. Ideally for a good ID of the difficult ones you want a female and a male, and the males are trickier...

The male genital segment has a "lid" hinged and resting on top of two vertical prongs at the very end - these are the parameres, and a vital part of the ID (side and hind view). The tricky part is inside, though - folded in under the "lid" is the aedegus, which needs to be very carefully hooked out (it's incredibly easy to damage). The tip of this incredibly fine structure is often expanded into an interesting - and taxonomically useful! - shape. Good luck! :-)

In this case, you don't need it though. For females like this with the upper part of the genital segment overlapping the lower by so much, it's almost certainly Cacopsylla brunneipennis. The rest fits too, I'm glad to say!

Finally, the face and genal cones are also an important aspect, so I'd keep the insect as intact as possible. For mounting females, I tend to stick them to card sideways, and fold the wings on the upper surface up so that they expose the abdomen. For males I usually try to do the same, then separate the genital segment, and as far as possible isolate all the bits, keeping them glued down toegther on the same mount.

We'll have to keep comparin notes on these, and I'me very happy to help out with psyllids - they're the group I'm trying to learn in most depth at the moment...

Joe

[Acutipuerilis]

Hi again. Here's one I dissected earlier. It's a male Cacopsylla visci. The genital segment has been removed from the tip of the abdomen, and is sitting separately, above left, but flipped over (just to confuse you - left and right are reversed!). I've magnified it, inset. The parameres are the dark structures on the right, and the aedegus is the fine pale brown line running up the middle; ignore the large dark bit on the left, because it's just not useful. The most important part of the aedegus for ID is the little exanded flange at the tip - the precise shape of that is vital for some species!



Any help? The RES guide for psllid adults is ok, but there is far more detail in Ossiannilsson's Fauna Entomologica Scandinavica vol. 26 (include almost all native UK species). I find it very hard to get very far with the RES volume alone, but the combination of the two works well.