Rates of Development, Survival and Predation of Immature Stages of Phytoseiulus Longipes (Acari: Mesostigmata: Phytoseiidae)

Abstract

Larvae of Phytoseiulus longipes do not feed. Thus, the purpose of this research was to determine the functional response as well as developmental and survival rates of the nymphal stages of this predator on the egg stage of the prey Tetranychus pacificus. The egg consumption for both immature stages increased smoothly with a negative rate reaching a plateau (type II response). To complete their development, the protonymphs and deutonymphs consumed mean minimums of 3.15 and 3.56 eggs, respectively, at a prey density of 20 per excised leaf arena. The mean daily developmental and survival rates also showed a curvilinear rise to a plateau. These plateaus for both developmental (71%) and survival rates (100%) were obtained at a prey egg density of 20 for both nymphal stages. Attack coefficients and handling times for both predator stages were estimated using several curve fitting models. All these models indicated a higher value of attack coefficient and a lower value of handling time for deutonymphs as compared to protonymphs. These findings, combined with the knowledge of adults' predation response, foraging behaviour and prey preference, indicate this predator's overall potential as a biological control agent against web-spinning spider mites such as the Pacific spider mite.