Population Genetics and Gene Variation in Primary and Secondary Screwworm (Diptera: Calliphoridae)

Abstract

Allozyme variation in screwworm, Cochliomyia hominivorax (Coquerel), and secondary screwworm, C . macellaria (F.), populations from northwest Costa Rica was examined . Variability was observed in 11 of 13 enzyme loci and the frequency of the most common allele was <0 .95 for 5 loci in screwworm . In secondary screwworm, 12 of 13 loci were variable and the frequency of the most common allele was <0 .95 for 6 loci . Expected heterozygosities were 0 .149 and 0 .160 for screwworm and secondary screwworm, respectively . Goodness-of-fit statistics for Hardy-Weinberg equilibrium and Wrights F statistics indicated that both species are panmictic with no evidence of population substructuring. Nei ' s genetic distances were 0.000-0 .001 for intraspecific comparisons and 0 .899-0 .916 for interspecific comparisons . The data indicate a high level of gene flow between populations within each species.

Population Genetics and Gene Variation of Stable Fly Populations (Diptera: Muscidae) in Nebraska

“…Octanol dehydrogenase (ODH), stained the same enzyme as formaldehyde dehydrogenase (FDH). This phenomena was observed in blowflies (Taylor and Peterson 1994) and mammals (Hur and Edenberg 1992).…”

“…High levels of intraspecific variation were detected in primary screwworm, but like stable fly, the secondary screwworm exhibited a single haplotype. Levels of allozyme variation were similar for these 2 species (Taylor and Peterson 1994). The pattern of variation may be the result of the historical dispersal patterns (Avise 1987).…”

“…Electrophoresis equipment and methods were similar to Taylor and Peterson (1994). Stain recipes were derived from Munstermann (1979Munstermann ( , 1980.…”

Population genetics and gene variation in screwworms (Diptera: Calliphoridae) from Brazil

“…Polyacrylamide gel electrophoresis was used for this study. Techniques were the same as those reported by Taylor and Peterson (1994). Heads were removed from each fly and stored individually for use in future molecular genetic studies.…”

“…(1982) proposed that NWS was a complex of reproductively isolated populations in North America. Subsequent studies failed to find evidence of population sub structuring (LaChance et aI., 1982;McInnis, 1983;McInnis et a/., 1983;Dev et a/., 1986;Krafsur and Whitten, 1993;Taylor and Peterson, 1994) and NWS was successfully eradicated from North America in 1991 (Vargas-Teran, 1991). Unfortunately, none of these studies included NWS populations from South America.…”