On the source of sterols in the green peach aphid, Myzus persicae, reared on holidic diets

Abstract

Cultures of Myzus persicae were maintained for five generations on holidic diet lacking sterol. A method to incorporate cholesterol into the aqueous diet is described. Addition of cholesterol to the diet (at 2.5 μg ml −1) reduced the larval development time of apterous M. persicae raised to the fourth generation on cholesterol-free diet by 12–16%, but had no significant effect on their teneral weight, the number of offspring deposited or the birth weight of their offspring. The symbiotic microorganisms in the aphids' mycetocytes were disrupted by treatment with the antibiotic chlortetracycline. These “aposymbiotic” aphids produced viable offspring on the diet containing cholesterol, but on the cholesterol-free diet development of the embryos was halted prior to germ band formation. These data suggest that the symbionts may synthesize sterols, which are required for embryogenesis of the aphid on diets. The possible involvement of microbial contaminants in the diet or gut microflora of the aphid in the sterol nutrition of M. persicae is excluded by rigorous microbiological studies.