Environmental Control of Nymphal Development and Diapause in Three Subtropical Populations of a Cricket, Modicogryllus confirmatus Walker (Orthoptera : Gryllidae)

概要

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The effects of photoperiod and temperature on nymphal development were examined in three subtropical populations of a cricket, Modicogryllus confirmatus Walker derived from Ishigaki Is., Yonaguni Is. and Okinawa Is. in the Ryukyu islands. The duration of nymphal development was longer when the photoperiod was shorter and the temperature lower. The development of nymphs reared at 13L(light)-11D(dark) showed a graded response to photoperiod ; the developmental rate was intermediate between the rates observed under short-day and long-day conditions, respectively. To determine if nymphal development at a short photoperiod was suppressed at a specific instar, head widths measured at various intervals after hatching were compared between short-day and long-day crickets. Nymphal development was suppressed at mid and/or late instars in short-day nymphs, indicating that these crickets entered diapause. No consistent difference was found in nymphal development between the long-winged and short-winged morphs. In spite of the small differences in latitude and temperature conditions between the collection sites, geographic variation was observed in nymphal development ; the higher the latitude the greater the degree of developmental retardation under short-day conditions.
日本昆虫学会の論文
2000-12-25