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For Insects, Spiders & Their Kin
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Photo#416107
sawfly with parasites

sawfly with parasites
Naches Trail Preserve, Pierce County, Washington, USA
June 24, 2010

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sawfly with parasites sawfly with parasites

Moved

Moved

Parasites
I expect that these are eggs of Tryphoninae, as the one on the left side of this image appears to have a stalk. Tryphoninae insert their eggs in the skin of the host. The larva of the tryphonine doesn't develop until the host larva spins its cocoon.

 
Interesting,
thanks!

 
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Evidently, the behavior of not feeding until the larva makes the cocoon pertains mostly to the tryphonines that parasitize sawflies. At least some of the minority of tryphonines that parasitize lepidoptera consume the host larva before it pupates and then spin their own cocoons. Beatriz Moisset has just posted some remarkable photos, and a video too, of such parasitoid feeding here. As for what the eggs look like before they are inserted in the host larva, there is a photo here. Some Tryphoninae, particularly those of the genus Polyblastus, carry multiple eggs on the ovipositor.