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Friday, 15 August 2014

Parsnip Moth update.

Further to Peachy Steve's find of a colony of Parsnip Moth larvae at Sowerby Bridge I took half a dozen home to rear through. Just one of them managed to reach the pupal stage, the other five were all parasitised by a species of Chalcid wasp. At first I thought they had all been "stung" multiple times but in fact that was far from the case. I sent a couple of photos off to wasp expert Dick Askew and here is his reply:

"Hi Charlie,
The parasitoid larvae in the Parsnip Moth caterpillar look to me like those of Copidosoma. This is in family Encyrtidae (Chalcidoidea) and they are polyembryonic, a brood of very many individuals all of the same sex developing by division of a single egg. I do not know whether or not yours will overwinter, but if they do it will probably be as fully grown larvae (ie. much as they are now). Best to keep them in a shed or outhouse."

Above, you can clearly see the dozens of grubs through the larval skin - nice!
Below, one I inspected earlier to see why the larva wasn't pupating as expected.


Steve Blacksmith said...

Worthy of a horror film script!
Thanks for passing on the pics and the info.

AndyC said...

Nice breakfast time reading............

charlie streets said...

Sorry Andy, hope you managed to keep your cornflakes down :-)

It's amazing how all those grubs have developed from just a single egg laid in the host. With some species broods numbering in to their thousands are produced from just one egg.

In one of my Parsnip caterpillars it looks like all the grubs have pupated in synchronicity and turned a dark brown - maybe they'll all emerge together.

AndyC said...

Looking forward to those pics..

AndyC said...
This comment has been removed by the author.
charlie streets said...

They've all hatched, all 102 of them :-)

Click on the link: