Friday, 8 August 2008

Another Bumblebee parasite

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.


Aynia said...

This is an amazing piece of information. Not sure I'd recognise the fly if it landed in my garden though.

Pam said...

Can't tell you how much I love the name Bombus Bohemicus!How much like human life is all this! There's the bumble bee going about its hardworking day, doing the right things,flat out ,but there's always someone waiting in the wings to take advantage!All I can say to these little bees in sympathy is what people say to me "they saw you coming!".

Stuart said...

Aynia...the more I study our wildlife, the more amazing I find it. There's a lot going on right under our noses.

Pam...Yes, I love it too..great name. The relationships between species and between species and their environments engross me more as each day passes. I know of very long chains of species dependencies where one action on our part can have completely unexpected outcomes elsewhere. It reminds me of the old computer programming adage..."fiddling x will always diddle y, no matter how unlikely".