Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!think.com!sdd.hp.com!caen!uwm.edu!linac!att!princeton!phoenix!unasmith From: unasmith@phoenix.Princeton.EDU (Una Smith) Newsgroups: sci.bio Subject: Re: Mutant flies Message-ID: <10091@idunno.Princeton.EDU> Date: 27 May 91 18:28:36 GMT References: Sender: news@idunno.Princeton.EDU Organization: Princeton University Lines: 65 cphoenix@csli.Stanford.EDU (Chris Phoenix) writes: >>>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. [stuff deleted] isaak@imagen.com (mark isaak) writes: >>This sounds like the screwworm fly, native to Mexico/southern USA. On the topic of gross insect parasites, there are the botflies of Central and South America. The females lay eggs under the exposed, soft skin of particular host species (there is a botfly that prefers humans above all other hosts). The larva develops a barbed tail, much like a harpoon, which it works down through the muscle tissue of the host, and snorkel-like breathing tubes which it extrudes through the entrance hole in the host's skin. They don't crawl around; I believe that they absorb nutrients through their skin. As larvae, they excrete antibiotics, but once they pupate, infection sets in and the local swelling forces the pupa out through the entrance hole. Infestation does not ordinarily cause death, although it may contribute to the ill-health of a host. Dr. Katie Milton, a primatologist, believes that due to the decline of many primate species in the neotropics, botfly species that commonly infest various monkeys are being forced to switch to human hosts (and, lucky for them, there are lots of human hosts around, since humans are directly replacing the monkeys). callahan@cs.jhu.edu (Paul Callahan) writes: >If "wipe out" means what it sounds like, isn't there a significant ethical >issue involved? I'm not convinced people have the right to cause the >extinction of a species even if it sometimes threatens human life. Well, then, would you prefer that small pox be allowed to persist somewhere in the world? Don't worry too much; "eradication" refers to eliminating the parasite in domestic animals only. There is very little concern about the effects of the parasite on wild "reservoir" species, except among conservationists. Perhaps it would also make you feel better to keep in mind that the activities of human beings has led to the introduction of a foreign species to a new environment; neither host nor parasite is entirely prepared to deal with the consequences. Under such circumstances, isn't it more OK for human beings to fix the mess they made. True, it's arguable whether it makes any difference that humans introduced an organism to a new environment. >What are the mitigating circumstances? The fact that it's a recent mutation? There's no "mutation" in evidence here. >The fact that it's "just" an insect? Certainly, humans do not hold all other species to be equal. Is this wrong? Is this a habit that we can change? Should we? - Una Smith School of the Environment, Duke University