Spider w/ parasititic larva? - Araneus diadematus

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I've placed this image on the info page. Thanks.

… Lynette Elliott, 14 October, 2013 - 9:16am

Moved to A. diadematus

Moved from Spiders. Yes, I agree. I don't see a lot of parasitic larvae on these, so that's a nice find.

… Lynette Elliott, 27 August, 2012 - 9:29am

Moved

Moved from ID Request. Just thought I should get a second opinion on A. diadematus because the cross is missing..

… Kyron Basu, 27 August, 2012 - 2:15am

Polysphincta larva…

The ichneumon wasp genus Polysphincta are parasitoids of many adult spiders, some of which even overwinter as larvae on the spider or in the spider's nest.

See reference here.

… Ross Hill, 27 August, 2012 - 1:13am

Thanks

Very interesting. I imagine this spider would mature next year, so maybe the larva will overwinter with it, then. Thanks!

… Kyron Basu, 27 August, 2012 - 2:13am

The spider is doomed, and at this time of the year I wouldn't be surprised if the larva takes only a couple more weeks to pupate (at which time it kills and eats the rest of the spider), though that depends on your climate.

Since the spider has no chance, you should capture it and keep it in a large container. It will go about its normal business of capturing and feeding on insects as the larva feeds on it. Right before the larva pupates it injects hormones into the spider which cause it to make an uncharacteristic tangled web in which the larva will hang as a pupa. After the web is built the larva kills and eats what it can of the spider, the then spins a cocoon around itself. If you keep it in the jar it will later emerge from the cocoon (in a week or two?) as an adult insect. At that time you can get pictures and post them to BG for an ID.

It's an interesting process to watch. I've done it with a few larva-parasitized spiders I've come across. The larvae I observed grew quickly.

Here is the adult wasp that developed from one of the larvae I was watching:

… John Sloan, 27 August, 2012 - 12:31pm