Life History Studies on the Predatory Mite Agistemus exsertus1

Abstract

The life history of the predatory stigmaeid mite Agistemus exsertus Gonzalez (Acarina: Stigmaeidae) was studied, using the 2 tetranychids Tetranychus cinnabarinus (Boisduval) and Eutetranychus orientalis (Klein) as prey. Eggs of E. orientalis accelerated the development of larval and nymphal stages more than did eggs of T. cinnabarinus. At 28-30°C, average developmental time from larva to adult female and male of A. exsertus was 4.4 and 4.5 days, respectively, when fed on E. orientalis, whereas it was 6.3 and 5.9 days on T. cinnabarinus. A diet of tetranychid eggs prolonged adult predator survival markedly more than a diet of postembryonic stages. Female A. exsertus lived 28-30 days on tetranychid eggs, whereas those reared on postembryonic stages survived 18 days. Females of the predator laid more eggs on a diet of tetranychid eggs (80-81) than on a diet of postembryonic stages (33-40). A. exsertus developed, survived, and reproduced successfully on either tetranychid species.