Fungal infection or parasitism? - Euplectrus

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After further reflection, I think the black things could be meconium--the wastes voided by the Euplectrus larvae just before pupating, like the yellow piles in this image of eulophid pupae:

[Edit]: Here's a paragraph salvaged from a dead page on the U-CA Riverside website (which I accessed by clicking the "cached" link in a Google search):

"Euplectrus has interesting pupation habits. When the larvae finish feeding on the host and have completely sucked out the fluid contents, they leave the dorsal position and seek the underside of the deflated host, where they arrange themselves transversely, in a single orderly row in some cases, and prepare to pupate. A light weblike cocoon is formed which binds the host remains to the leaf, the latter thus serving as a protective covering. Several authors have called attention to the fact that the material from which the cocoon is spun is derived from the Malpighian tubules rather than from the salivary glands and that the slender tapering tip of the abdomen of the larva serves as an "arm" in the construction. The meconium is cast by the prepupa, and sometimes it is ejected from the cocoon. The pupa lies upon its dorsum and is attached to the substrate by means of the last larval exuvium, which envelops the tip of the abdomen."

The meconium is not described, but the same site describes the meconium of another eulophid as being in the form of black pellets. It appears that in this case not all of the larvae were able to fit under the caterpillar, so some made cocoons on top of it. A few seem to have done so in the image I linked to in my last post as well.

… Charley Eiseman, 13 December, 2008 - 12:39am

Black bits on the leaf

While searching for identification of some black pupae of a parasitoid, I came across this photo of the circle of black pupae. They are pupae of a parasitoid. I found a duskywing caterpillar on oak. Within a day, parasitoids emerged from the larvae. Three days later, they made these little black pupae. This is the second time I've found them (the first emerged as little flies and I will be taking them for identification at the University of Florida). Today I found another duskywing caterpillar with the same parasitoid larvae freshly emerged from the caterpillar. I have photos to submit of them as larvae and as pupae. It will be great to find the actual identification of these critters!

… Edith E Smith, 3 November, 2009 - 7:09pm

Fungi. No, parasites! ,,,actually....Fungi!

The poofy clusters of hairs look like empty wasp cocoons, but since there are hairs all over this insect, I think that they are actually fungi. You could try coming back tomorrow and rephotographing it to see if they've grown at all.

… Mark Fox, 13 October, 2008 - 8:42am

another thought

I can't tell from the picture, but it just dawned on me that these might perhaps be seeds (with their little tufts of fluff attached) that happened to stick to the dead caterpillar. They remind me a little of the seeds of Salix or Populus, but I suspect they aren't those. And then again, they could be spore bodies of some fungus afterall (or ??? little seeds stuck to fungus growing out of the caterpillar).

… David J. Ferguson, 10 December, 2008 - 5:51pm

Maybe...

Euplectrus species seem to spin loose cocoons somewhat reminiscent of what is shown in these photos

That still wouldn't explain the black things, though...

… Charley Eiseman, 12 December, 2008 - 8:36pm

another thought

This looks rather similar. So, what happens to the pupal shell when the adult insect emerges. The photo is just slightly out of focus, so it's hard to really tell what the little dark bits look like. The impression is of an oval solid object, but maybe curved thin bits? Perhaps these little dark things are bits of pupal shell still stuck to the cocoons? Or - what he said (below) :)

… David J. Ferguson, 15 December, 2008 - 2:42pm

pupal skins

I think they may still be in the cocoons (which they should be, as far as I know--I haven't come across any mention of mobile wasp pupae in my research)-- if you follow the outline of the right side of the caterpillar, there are two spots along the top half where something dark inside the alleged cocoons breaks up the outline. Looking at the other cocoons I can imagine similar dark spots, but these two are more unambiguously un-imaginary.

… Charley Eiseman, 15 December, 2008 - 3:07pm