Aggregations of dead Leafhoppers in rotting timber

[poschiavanus]

I noticed a couple of bits of shattered and rotting trunks today and thought I'd pull them apart and see if there was anything interesting. I noticed a couple of dark cylinders at end of tunnels and assumed they were pupae or other wood feeding insects.

However under the microscope at home they are densely packed groups of (very dead) leafhoppers: probably of more than one species but several can be identified from patterns on the vertex and pronotum as Eupterycyba jucunda. There are lots of small mites obviously feeding on them.

I don't really know how or why they got there. There is a small amount of what may be silk so possibly a spider's larder. The timber has a damp rot.

Has anyone else seen anything like this?

[Jason Green]

It could be a sphecid wasp or related, provisioning it's nest with food for the developing larvae.

Any sign of pupae towards the end of the tunnels?

[poschiavanus]

None as yet: I think I'll have to go and bring back a bigger bit of wood! (When the rain stops)

[Acutipuerilis]

I think it's very likely to be spider. Eupterycyba can be abundant around particular trees (alder), and I have seen spiders seeming to feed almost exclusively on them at the richest time of year.

[Jason Green]

Do you have/can you get any phgotographs of this, please?

[poschiavanus]

Originally Posted by Jason Green

Do you have/can you get any phgotographs of this, please?

Took these today:



Left to right zooming closer in each time.

[Jason Green]

What sort of access was there, for the insect of course, to get to where the cicadellid remains were prior to the trunk being opened-up? A small sphecid wasp would use an ex-beetle hole/tunnel, whereas spiders are more likely if the thing was more open and accessible.

[poschiavanus]

If you look at the second picture you can see a tunnel containing frass running from the leafhoppers towards the bottom left of the picture. The bark is at the lower edge of the image.

The wood has extensive beetle workings: I've collected a few larvae but haven't run them down to family yet.

[tristanba]

Interesting, there certainly are a number of Eupterycyba jucunda! I wonder if it could be the nest chamber of a wasp which provisions its larvae specifically with leafhoppers, as it seems a bit non-random for a spider. Perhaps a Mimesa/Mimumesa sp?

[Jason Green]

Yes, I was thinking on the quiet the sub-family Pemphredoninae. A number of that type use Cicadellids, and nest in beetle holes/rotting wood.