Thermal requirements for the development and reproduction of Nysius huttoni White (Heteroptera: Lygaeidae).

Nysius huttoni White is an economically important pest of wheat and brassica crops in New Zealand. Because of its frequent presence in export fruit packages, it is also considered an important quarantine pest to countries that trade with New Zealand. To provide critical information for the pest risk analysis, forecast and management of N. huttoni, we investigated the effect of five consistent temperatures (10, 15, 20, 25, and 30 degrees C) on its development, survival and reproduction. At 10 degrees C both eggs and nymphs did not develop but the latter grew. Nymphs could survive 10 degrees C for >1.5 mo, with the fifth instar nymphs surviving for up to 145 d. Adults could live for at least 100 d at this temperature. This species could not complete its lifecycle at or below 15 degrees C. Between 15 and 30 degrees C, fifth instar stage was significantly longer than other nymphal stages. Egg hatch rate and total survival rate for all stages were significantly higher at 20 degrees C than at other test temperatures. The developmental rate of different life stages increased linearly with the increase of temperatures from 15 to 30 degrees C. The estimated low temperature threshold for the completion of lifecycle was 11.9 degrees C, and that for mating and oviposition was 12.3 and 16.8 degrees C, respectively. The thermal requirement for completing a life cycle of N. huttoni was 625 DD. The time needed for completing a life cycle was similar for both sexes. Temperature had little effect on adult body weight and sex ratio. Implications of the above findings are discussed.