Earlier in the year I showed the Cuckoo Bumblebee Bombus bohemicus, which is parasitic on the bumblebee Bombus lucorum s-l, by taking over the nest and using it to raise its own young.
The Conopid fly Sicus ferrugineus is another parasite on bumblees, but this time the behaviour is a bit more personal. It sits in wait beside a convenient flower:
And then leaps out to staple an egg upwards into the soft abdomen of a passing worker bumblebee. Here's a close-up of the fly, showing the upturned abdomen:
Note how the abdomen curves right round - in almost a full circle - until it's pointing upwards.
And this close-up shows the upward-pointing ovipositor.
Recent studies have indicated that a parasitised bumblebee will change its feeding pattern after the egg has been laid. Perhaps this is to make sure the diet suits the fly rather than the bee.
It's tough out there.