The expensive nuisance of the screw work fly is being met by scientists in Puerto Rico who are using the flies against themselves.
GV,CU Aircraft prepare to take off (3 shots)
CU,SV Technicians prepare sterile screw worm fly (2 shots)
SV Larva boxes loaded onto plane
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CI,SV Larva thrown from plane (3 shots)
CU Larva on plate in labs scientist explains
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SCIENTIST: "The larva stage of a screw-worm fly is a very serious pest to livestock, in that it lives on live tissue. We're using sterile male flies. The female fly will only mate once in her life. If she has mated with one of our sterile flies then these eggs, of course will not hatch."
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This film includes a comment by a Department of Agriculture scientist about the method:
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Background: The expensive nuisance of the screw work fly is being met by scientists in Puerto Rico who are using the flies against themselves.
A major pest in the southern United States from Florida to Texas and throughout the Caribbean, the screw worm fly lays its eggs in scores of open places in the skins of animals (and, sometimes, humans). The larva (the actual "screw worms") cause festering and infection, sometimes leading to death.
In the late 1950s major agricultural agencies, under the coordination of the U.S. Department of Agriculture, embarked on a programme to find a way to combat the flies.
Very simply, they came up with the idea of suing sterile male flies to decimate the population growth of the flies.
Male flies are subjected to radiation, making them sterile. Released by the thousands over wide areas, they mate with females, who of course produce no offspring. Since the female fly mates only once in their life cycle, that generation of lies produces no new flies.
The programme was first tried in the State of Florida, and eliminated the screw-worm from that state by the mid 1960s -- and from all the other states where it has been used.
The male flies used in the Puerto Ricco programme are not wild -- they're laboratory-bred. Female flies seem to make no differentiation between the two.
The sterilised males are loaded onto light planes and scattered over large areas of the Puerto Rican countryside.