Responses of three Orius species collected in Kagoshima to different rearing temperatures and photoperiods

The effects of temperature on the development of three Orius species, O. sauteri, O. minutus and O. strigicollis were examined at 17, 20, 23 and 26degreesC by using eggs of the Mediterranean flour moth (Ephestia kuehniella Zeller) as a food source. The effects of photoperiod on the reproductive diapause in these Orius species were also examined under 15L-9D, 14L-10D, 13L-11D, 12L-12D, 11L-13D and 10L-14D at 20degreesC and under outdoor conditions from September to November in 2001 in Higashi-ichiki, Kagoshima. Developmental times from egg to adult were different between the three species under low temperatures, 17 and 20degreesC. Developmental zero (T-0) and the thermal constant (K) from eau to adult were 11.0degreesC and 259.1 day-degrees in O. sauteri, 10.3degreesC and 281.3 day-degrees in O. minutus and 10.0degreesC and 281.9 day-degrees in O. strigicollis. Estimated annual number of generations in the three species was calculated to be 8 based on the mean air temperature in Kagoshima. Estimated critical photoperiod for diapause in O. sauteri and O. minutus was between 11L-13D and 12L-12D, while the diapause rate of O. strigicollis was low, 25.0% even under 10L-14D. In outdoor conditions, ca. 25% of O. sauteri cohorts reared from early September entered diapause. Further, ca. 80% of the cohorts of the three species reared from early October entered diapause.