Flight response, body weight, and lipid content of Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae) as influenced by strain, season and phenotype

Effects of geographical origin of strain, season of field collection, genetic background, and number of generations of laboratory rearing on flight initiation, body weight, and lipid content of lesser grain borer, Rhyzopertha dominica, were studied. Significant differences in flight initiation, body weight, and total lipid content occurred among the four field strains collected from Kansas, Oklahoma, Texas, and Mexico. Flight activity tended to be higher for strains with higher average body weight. Oleic, palmitic, and linoleic acids accounted for about 95% of all fatty acids present in the strains tested. However, the percentage of lipids per fresh body weight was not significantly different among these four field strains. Beetles collected in summer tended to fly more and have a higher percentage of lipid content than beetles collected in spring and autumn. Results from crosses between strains with high and low flight responses suggested that the female contributes a higher proportion of additive genetic variance for flight initiation than the male. Rearing for 17 generations in laboratory conditions had no discernible effect on flight initiation of a strain of R. dominica collected from the field. Thus, flight behavior can persist for many generations of laboratory rearing.