Saturday, 30 August 2008

Small Tortoiseshell parasitoids - 30th August

There are suspicions that Sturmia bella a parasitoid fly of Nymphalidae butterflies, relatively new to Britain, may be responsible for the recent decline in Small Tortoiseshells. I collected 30 Small Tortoiseshell larvae from my garden last weekend and all but one successfully pupated. Last night however there was a mass emergence of parasitoid grubs (38 at the last count) from about 15 of the butterfly chrysalids, which quickly pupated. Here is one of the grubs that emerged this morning, which had me quickly scrabbling for my camera, and a couple of other pictures. They will all be sent off for expert identification to see if they are S.bella. The remaining 14 Small Tortoiseshell pupae look okay, but time will tell...

Pictures by Keith Balmer

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