Gomi Tadashi
National Institute of Sericultural and Entomological Science, Ohwashi, Tsukuba, Ibaraki 305, Japan Fax: +81-298-38-6028, , , , , , JP.
Oecologia. 1997 Jul;111(2):160-165. doi: 10.1007/s004420050220.
The fall webworm, Hyphantria cunea Drury (Lepidoptera: Arctiidae), was introduced from North America to Japan half a century ago. The critical photoperiod for diapause induction and its temperature dependence, as defined by the difference in the critical photoperiod between 20 and 25°C, were investigated in order to understand the mechanisms behind a shift from bi- to trivoltine life cycles. The critical photoperiod for diapause induction was shorter in the southern trivoltine populations than in the northern bivoltine populations, and this was more marked at 25°C than at 20°C. Although the critical photoperiod showed a positive correlation with the original latitude, the correlation was relatively low at both temperatures. Conversely, temperature dependence of the critical photoperiod for diapause induction correlated negatively with the original latitude. The trivoltine populations showed greater temperature sensitivity than the bivoltine populations. These results suggest that an increase in temperature sensitivity of the diapause response to photoperiods was involved in the shift to a trivoltine life cycle. The crossing experiments suggested that the photoperiodic control of diapause induction and its temperature dependence are under polygenic control without sex-linkage.
落叶松毛虫，舞毒蛾（鳞翅目：灯蛾科），半个世纪前从北美引入日本。为了了解从双化性生命周期向三化性生命周期转变背后的机制，研究了滞育诱导的临界光周期及其温度依赖性，其定义为20°C和25°C之间临界光周期的差异。南部三化性种群中滞育诱导的临界光周期比北部双化性种群中的短，并且在25°C时比在20°C时更明显。尽管临界光周期与原始纬度呈正相关，但在两个温度下该相关性都相对较低。相反，滞育诱导的临界光周期的温度依赖性与原始纬度呈负相关。三化性种群比双化性种群表现出更高的温度敏感性。这些结果表明，滞育对光周期反应的温度敏感性增加与向三化性生命周期的转变有关。杂交实验表明，滞育诱导的光周期控制及其温度依赖性受多基因控制，无性别连锁。
