Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!think.com!spool.mu.edu!agate!stanford.edu!csli!cphoenix From: cphoenix@csli.Stanford.EDU (Chris Phoenix) Newsgroups: sci.bio Subject: Mutant flies Message-ID: <19490@csli.Stanford.EDU> Date: 26 May 91 09:01:45 GMT Article-I.D.: csli.19490 Organization: Center for the Study of Language and Information, Stanford U. Lines: 36 I read recently on some group (maybe this one?) that there is a recently- appeared type of fly that lays eggs in living tissue, and the maggots eat the tissue, with often-fatal results. Apparently it's enough of a threat that there's an international effort to wipe out the flies before they spread. It seems like such a fly would have to arise from two mutations/changes at once: First, to lay its eggs in living rather than dead tissue; second, to have its maggots able to eat living tissue. I've just had confirmation that maggots are sometimes used to clean wounds, so it appears that with "normal" flies, they are not a danger. As far as I know, "normal" flies also do not lay eggs in living tissue either. (Though I don't know that much...) So we have two behaviors/capabilities, one of which most (or all) flies don't do, and one of which would cause a waste of the fly's resources. And yet we have this fly that has learned to do both, probably within a short time frame, and seems to be successful at it. From what I know of evolution and natural selection, this doesn't make sense. 1) Flies have pretty short generations, which means they've had a lot of time to optimize. Why should they suddenly change? 2) How could a fly learn two behaviors at once, neither of which appears useful by itself? Now that I think of it, the original post mentioned that cow's vulvas are one of the target areas of the new fly. I suppose laying eggs there could be useful even without the ability to eat the cow if the maggots could hitch a ride as the cow defecated. Does anyone know if this happens? I apologize if this post is too gruesome... -- Chris Phoenix cphoenix@csli.stanford.edu #insert #insert #insert