Sunday, 21 November 2010

Louse Flies!

A louse fly, family Hippoboscidae

Louse flies are members of the family Hippoboscidae. They are dorso-ventrally flattened blood-sucking muscoid flies, the adults of which live as external parasites of birds and mammals. They fossick amongst the hairs or feathers and the flattened body plan aids in this activity. Some have complex life histories involving "adenoptrophic viviparity". This means that eggs are nourished and hatch within the female and living larvae are deposited rather than eggs. This happens in a number of unrelated flies, the most awful example of which is an Australian brown blowfly.

I have often seen hippoboscids scuttling about on the wings and bodies of Brush Turkeys and wondered how to photograph them. To my surpsrise one appeared on the light sheet. A variety of birds and mammals play host to these flies and wallabies have some special ones. I have no idea the host of this fly, but I have myself been mistaken for a host by hippoboscids. They alight and when they discover their mistake are quick retreat.Note the needle-like mouthparts. They use this beak to penetrate the tissues of the host and withdraw blood.


Denis Wilson said...

I remember finding these things when Bird Banding - mostly on small Passerines.
They give me the creeps for their ability to hide and also how hard they are to "squash" (which is my instinctive reaction I am ashamed to say).
I also remember seeing young nestlings with large maggots beneath the skin, which were assumed to be there creatures, as they are the only flies I know of which infest birds.
Simplistic judgement, but...
I have also had them appear on me, when handling occasional fresh road killed birds.
They make my flesh crawl.
At least you were objective enough to get some good photos.

Ted C. MacRae said...

I've seen these on my arms a few times when I lived in California. I'm not normally a squeamish type, but these things just give me the willies!

randomtruth said...

Are these the kind that drop their wings when they find a host they like? I think I see them in the Sierra Nevada often.

Mr. Smiley said...

I recall these flies form my California days. Yes, they are the ones that drop their wings once on a host. I suspect they are fairly host specific even though dropping the wings would seem illogical with that scenario. Some insects just make mistakes.