Photoperiod and temperature studies to determine whether diapause is found in successive generations of the African phytoseiid, Euseius fustis (Pritchard and Baker) (Acari: Phytoseiidae)

Photoperiod and temperature conditions known to induce diapause in tropical arthropods were tested on two generations (G sub(0) and G sub(1)) of the phytoseiid, Euseius fustis. Failure to lay eggs or a pre-oviposition period longer than 15 days were the criteria used to determine whether females were in diapause. Females reared from egg to adult and held throughout adult life under cyclic temperatures of 29/20 degree C in combination with long photophases of 16L:8D and 14L:10D showed no indication of aestival diapause. Similarly, hibernal diapause was not induced in females reared under a constant temperature of 18 degree C and a photophase of 8L:16D. Under the various test conditions, females initiated oviposition within an average of 4 days. Overall, pre-oviposition patterns for G sub(0) and G sub(1) females were similar under the same test conditions. Reproductive patterns based on the mean number of eggs per female per day varied only slightly between generations for the same treatments. No behavioural or morphological attributes associated with diapause were observed.