The Control Mechanism Of Life Cycle Of Two Crickets, Tartarogryllus Minuscule And Teleogryllus Emma

Photoperiodism is one of the most important phenomena implicated in the control of seasonal development and life cycles in insects living in the temperate climatic zone. Because photoperiod or daylength provides insects and other organisms with a reliable seasonal cue by which their life cycles are synchronizied with the season. The effects of photoperiod on nymphal growth and adult reproduction were investigated in a cricket, Tararogryllus minusculus. The mean duration of nymphal development is 60 days in constant long phtopheriod(LD 16:8h) at 30℃.But the mean duration of nymphal development is over 120 days in constant short phtopheriod(LD 12:12h) at 30℃.Nymphal development is much rapid when the nymphs are transferred from LD 12:12h to LD 16:8h at 7 days and 35 days after hatching. Nymphs mature more rapidly when transferred at 7days than that transferred at 35 days from LD 12:12h to LD 16:8h. However, nymphal development is not prolonged when the nymphs are transferred from LD 16:8h to LD 12:12h at 7days and 20days after hatching. At the same time, there is no difference in nymphal development between them which are transferred from LD 16:8h to LD 12.12h at 7 days and 20 days after hatching. The developmental suppression induced by short days may represent a form of winter diapause that is termination by long days. Photoperiod take effect on the reprduction output too. Adults in LD 16:8 h produce more total eggs than adults in LD 12:12h. But there is no difference between LD 16:8h and LD 12:12h in pre-oviposition and pre-hatching. Based on these observations and field-census data, it is suggested that this cricket has a bivoltine life cycle overwinteringing as nymphs in zhuzhou.Temperature play a important role on induction maintain and termination of diapause of eggs. The percentage of hatching are 14.7% 17.9% 36.9% when eggs incubated at 20℃ . 25℃ 30℃ . After chilling at 8℃ for 40 days or more, however, almost all eggs hatched, suggesting chilling has an apparent diapause-eliminating effect on Teleogryllus emma . When eggs chilled at 8℃ for 20 days were kept at 30℃ for 3 days or more before incubation 20℃. the hatching increase with the days at 30℃ prolonged. This facts suggest that high temperature play a important role in elimination diapause of T. emma. On the other hand, eggs chilled at 8℃ for 20 days were kept at 20℃ for 7 days or more before incubation 25℃, most eggs failed to hatching. These facts suggest that diapause intensity can be restored if eggs chilled insufficiently are exposed to a moderately high temperature. This reversible in...