The phenological response is among the most important traits affecting a species’sensitivity to climate.In insects,strongly seasonal environments often select for a univoltine life cycle such that one seasonal extrem...The phenological response is among the most important traits affecting a species’sensitivity to climate.In insects,strongly seasonal environments often select for a univoltine life cycle such that one seasonal extreme is avoided as an inactive stage.Through understanding the underlying mechanisms for univoltinism,and the consequences of its failure,we can better predict insect responses to climate change.Here we combine empirical data and simulation studies to investigate the consequences of an unusual diapause mechanism in a parthenogenetic matchstick grasshopper,Warramaba virgo,from arid southern Australia.Our field body temperature measurements indicate that this species is a thermoconformer and our laboratory studies of the thermal response of feeding rate imply strong constraints on winter activity.However,the species exhibits no obligate winter diapause,and eggs can develop in 1 month under constant temperatures approximating the mean soil temperature at the time of oviposition(summer).We show that diurnal temperature cycles exceeding a peak of 36℃ inhibit egg development in summer,and that this is sufficient to prevent autumnal hatching of eggs.Development is also strongly retarded below 24℃.Microclimate-driven simulation studies of egg development show that these thermal responses provide robust maintenance of a univoltine life cycle,thereby resulting in survival of heat stress as an egg(due to limited developmental state)and avoidance of cold stress as a nymph and adult(due to overwintering in the soil as an egg).展开更多
Diapause eggs of Bombyx mandarina Moore from Wujiang, Jiangsu Province, China, were used to study the artificial hatching of B. mandarina Moore. The results showed that the highest hatchability was obtained by instant...Diapause eggs of Bombyx mandarina Moore from Wujiang, Jiangsu Province, China, were used to study the artificial hatching of B. mandarina Moore. The results showed that the highest hatchability was obtained by instant treatment with hydrochloric acid （HC1, specific gravity 1.065-1.075） for 5 rain under 46℃. After the B. mandarina eggs were cold stored at 5℃ for 40 days, the highest hatchability was obtained by treatment with HC1 （specific gravity 1.092） for 6 minutes under 47.8℃. For the B. mandarina eggs that were stored at 25℃ for 28 d and then cold-stored at 5℃ for 0-100 days, the highest hatchability was obtained by treatment with HCI （specific gravity 1.092） for 6 rain at 47.8℃. The longer the cold storage period, the higher was the hatchability. Acid treatment on diapause eggs of B. mandarina for 6 rains at 47.8℃ with hydrochloric acid （specific gravity 1.092） before hatching in spring could obviously shorten the hatching stage and increase the hatchability.展开更多
基金This research was supported by Australian Research Council grants DP0450050 to MRK and DP160100279 to MRK and AAH.
文摘The phenological response is among the most important traits affecting a species’sensitivity to climate.In insects,strongly seasonal environments often select for a univoltine life cycle such that one seasonal extreme is avoided as an inactive stage.Through understanding the underlying mechanisms for univoltinism,and the consequences of its failure,we can better predict insect responses to climate change.Here we combine empirical data and simulation studies to investigate the consequences of an unusual diapause mechanism in a parthenogenetic matchstick grasshopper,Warramaba virgo,from arid southern Australia.Our field body temperature measurements indicate that this species is a thermoconformer and our laboratory studies of the thermal response of feeding rate imply strong constraints on winter activity.However,the species exhibits no obligate winter diapause,and eggs can develop in 1 month under constant temperatures approximating the mean soil temperature at the time of oviposition(summer).We show that diurnal temperature cycles exceeding a peak of 36℃ inhibit egg development in summer,and that this is sufficient to prevent autumnal hatching of eggs.Development is also strongly retarded below 24℃.Microclimate-driven simulation studies of egg development show that these thermal responses provide robust maintenance of a univoltine life cycle,thereby resulting in survival of heat stress as an egg(due to limited developmental state)and avoidance of cold stress as a nymph and adult(due to overwintering in the soil as an egg).
基金supported by the National Natural Science Foundation of China(30471309)the National Basic Research Program of China(2005CB121005).
文摘Diapause eggs of Bombyx mandarina Moore from Wujiang, Jiangsu Province, China, were used to study the artificial hatching of B. mandarina Moore. The results showed that the highest hatchability was obtained by instant treatment with hydrochloric acid （HC1, specific gravity 1.065-1.075） for 5 rain under 46℃. After the B. mandarina eggs were cold stored at 5℃ for 40 days, the highest hatchability was obtained by treatment with HC1 （specific gravity 1.092） for 6 minutes under 47.8℃. For the B. mandarina eggs that were stored at 25℃ for 28 d and then cold-stored at 5℃ for 0-100 days, the highest hatchability was obtained by treatment with HCI （specific gravity 1.092） for 6 rain at 47.8℃. The longer the cold storage period, the higher was the hatchability. Acid treatment on diapause eggs of B. mandarina for 6 rains at 47.8℃ with hydrochloric acid （specific gravity 1.092） before hatching in spring could obviously shorten the hatching stage and increase the hatchability.
