Monday, June 8, 2009

Assassin




Watching this little hymenopteran (can anyone help with the identification?), only about a centimetre long, working its way through the florets of the grasses around my garden pond, provided a chilling insight into this deadly parasite’s hunting technique. Equipped with a long egg-laying tube (ovipositor), it parasitized insect grubs inside the grass florets without ever seeing its prey. The pictures give a clue to how it manages this. It moved from floret to floret, pressing its antennae against each in turn (bottom picture). How did it find them? Was it scent picked up by its antennae tips, or did they detect vibrations from a wriggling, hidden victim? I have no idea, but what is certain is that as soon as it located a hidden host the parasite slid that stiletto-like ovipositor into a floret (top picture), presumably laying an egg in an unfortunate victim whose destiny was to be eaten alive by the hymenopteran's hatching larva.

6 comments:

  1. Fantastic, Phil.
    Sorry, can`t help with the id. This group can only be 100% id`d by examining the genitalia.

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  2. Thanks Dean, I guessed it would be a specialist job to put a name to it. Fascinating insect, though.

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  3. Gruesome, but nonetheless fascinating Phil.

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  4. Quite possibly a Lissonota setosa (Black Ichneumon Wasp).

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  5. One of the interesting things about its behaviour, Keith, was the methodical way in which it investigated every single grass flower floret - no escape for anything hiding inside

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  6. Thanks for the ID Myopicbirder - I find all these small hymenopterans really tricky to identify.

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