The release of a compound-chromosome stock in a vineyard cellar population of Drosophila melanogaster.

The prospect of autocidal insect control was investigated in a cellar population of D. melanogaster using a compound-chromosome stock. The released stock was synthesized by irradiating virgin female progeny derived from the cellar and crossing to a second-chromosome compound laboratory stock. Incorporation of an appropriate genetic background into the compound stock was tested in laboratory studies. Larval development to adult emergence and adult survival studies indicated the compound release stock to be relatively similar to the wild population, while behavioral tests detected no mating isolation between wild or compound genotypes. An unstable equilibrium point of compound frequency 0.7 was observed in population cage experiments with the two genotypes. Adults were released into the cellar at a 50:1 ratio in favor of the compound. Five hundred newly hatched compound-chromosome larvae were also released. Adult, larval and pupal samples were regularly made. The compound stock successfully bred in the cellar maintaining an adult frequency of at least 90% for 108 days after the release. The rapid decline in compound frequency after this period is thought to be due to the migration of inseminated wild-type females from wine storage areas adjacent to the cellar. The results indicate that a compound stock may limit the rate of population expansion in an area and may be a useful mechanism of autocidal control. It cannot be overemphasized that the probability of a successful release will be related to the level of understanding of the adaptive strategy of the population into which the release is made.