sianhilton: small black fly (17. Feb 2008 20:55)

Dear all

Does anyone know the identification and what it is doing although I could have a good guess?

While watching Lasius n iger at work in the garden they are often pestered by a tiny black fly that is trying to land on them I presume to lay eggs etc. In all the years I have observed ants I have often wondered it's purpose?

Regards

mpir: (18. Feb 2008 09:55)

I´ve heard that this method is the most promising one to keep Fire ants under control in southren USA. But I´ve no idea that this kind of flys exesist also in Europe.

The_Paranoid: (18. Feb 2008 10:05)

yep, the use one specie of flies from the Phoridae family for fire ant control. But this specie is specialized on fire ants... there are also Phoridae species in europe who are specialized on other ant species.
They lay an egg into the workers. the larva hatches, feeds on the ant and stays in the ants chitin-body until it's a fully developed fly.

tail__: (18. Feb 2008 10:07)

I know what you see, I saw them many times. They are phorid flies (Diptera: Phoridae), common ant parasites. The genus of this fly is Pseudacteon, they are a few species in Europe. Most probably it is P. formicarum, which is specific to Lasius. Female fly lay egg in alive ant, the larva eat the ant's flesh and eventually kill it. Dead ant is taken out from the nest, then the larva continues to grow in it's body and pupate. You can read more about them here:
http://www.nysaes.cornell.edu/ent/biocontrol/parasitoids/pseudacteon.html

mpir: (18. Feb 2008 10:18)

Thanks for the great link. I learn something new every day. :D

JimmyVe: (18. Feb 2008 18:48)

Very nice information. Good link to tail.

sianhilton: (19. Feb 2008 13:57)

Thank's tail very informative