Laboratory life history studies of the predaceous mite Typhlodromus athiasae (Acari: Phytoseiidae)

The biology of Typhlodromus athiasae Porath & Swirski (Acari: Phytoseiidae) was studied in the laboratory. When mites were fed on pollen of Carpobrotus edulis highest fecundity (1.5 eggs/day for 20 days) was obtained at 25°C, 70% RH and a photoperiod of L:D 16:8; lower or higher temperatures and humidities resulted in lower fecundity. Feeding on a spider mite, Tetranychus urticae Koch, resulted in a similar number of progeny, but apple pollen engendered less progeny. Fewer eggs were produced at L:D 10:14 than at L:D 16:8. Individual males fertilized an average of six virgin females. Presence of males with females throughout the 20 days of oviposition did not induce higher fecundity than a one-day male-female eo-occurrence. The sex ratio was M:F 1:2.6. Virgin females which mated late in their lives (at 30, 60, 90 and 120 days post-emergence) produced progressively fewer eggs, and for a shorter period, than early-mated females. At 25°C some females lived for 3-4 months after oviposition, but no such prolonged survival occurred at 21 oc or 29°C. Larval mites molted without feeding. These findings are discussed in relation to theories about the evolution of phytoseiid life histories.