Influence of food and temperature on development and oviposition ofEuseius stipulatus andTyphlodromus phialatus (Acari: Phytoseiidae)

The influence of feeding and temperature on life table parameters ofEuseius stipulatus (Athias-Henriot) andTyphlodromus phialatus Athias-Henriot was determined in laboratory tests. Both phytoseiids developed and reproduced readily when fed onCarpobrotus edulis (L.) pollen andPanonychus citri (McGregor) Intrinsic rates of increase (r _m ) at 25°C forE. stipulatus andT. phialatus were 0.197 and 0.126, and, when fed onP. citri, 0.129 and 0.144, respectively.Tetranychus urticae Koch offered as prey allowed normal development and oviposition ofT. phialatus, but no eggs were laid byE. stipulatus when fed on this spider mite. Eggs and honeydew ofAleurothrixus floccosus Mask. furnished sufficient nutrition for development of immatures ofE. stipulatus. Larvae ofPlanoccocus citri Risso, and honeydew and eggs ofA. floccosus, allowed adult survival but no egg-laying of the predaceous mites.Lorryia formosa Cooreman was not a favoured prey species.Life tables were calculated forE. stipulatus fed on pollen andT. phialatus fed onP. citri at constant temperatures of 18, 25, and 32°C. Maximum development was reached at 32°C, withr _m values of 0.225 forE. stipulatus and 0.179 forT. phialatus. In general, both phytoseiids showed medium to high total number of eggs per female and long oviposition periods when compared with other phytoseiid species.When mating took place at 32°C,E. stipulatus females were not able to lay eggs, thus suggesting an interference of high temperatures with fertilization in this species. No hatching was observed in eggs of either species when kept at relative humidities of 50% or lower. The possible significance of these responses is discussed in relation to population trends observed in the field.