Some factors affecting reproduction and sex ratios in two species of predacious mites, Phytoseiulus persimilis Athias-Henriot and Amblyseius andersoni (Chant) (Acarina: Phytoseiidae)

Abstract

Several factors were examined to determine their effect on the reproduction and sex ratios in two species of predacious phytoseiid mites, Phytoseiulus persimilis and Amblyseius andersoni, in the laboratory. The factors investigated included multiple matings, age of mating males, and food deprivation periods during the immature and adult stages. The results indicated that females of A. andersoni require multiple matings to maximize their reproductive potential but those of P. persimilis do not. Males of both species showed a high reproductive ability for more than 20 days and the total number of progeny produced by individual males exceeded 1000 and 500 in P. persimilis and A. andersoni respectively, under the experimental conditions. Following certain food deprivation programmes, females increased egg production and produced proportionally more male progeny, compared with females under constant conditions of abundant prey.