中华稻蝗五地理种群的卵滞育强度及生活史模式变异

为调查中华稻蝗Oxya chinensis的地理适应，自北纬42.3°至20.0°采集了5个地理种群的标本，比较了其子代的卵滞育发生、滞育强度及成虫虫体大小。结果表明: 不同的中华稻蝗地理种群显示了不同的光周期和温度反应模式。铁岭、济宁和泗洪种群的滞育不受光周期和温度的影响，滞育率均为100%。南方的长沙和海口种群仅部分卵进入滞育，海口种群在短日条件下的滞育率高于长日条件，卵期温度亦对其滞育有较大的影响，而长沙种群的卵滞育仅受卵期温度的调控。长沙和海口种群的卵滞育强度最弱，其次是铁岭种群，中间纬度的济宁和泗洪种群的滞育强度最高。在北方的一化性种群中，滞育强度随着纬度的降低而增强。成虫的虫体大小因栖息地纬度的变化而呈现复杂的变异，北方种群的虫体大小与栖息地纬度存在显著的负相关关系，而长沙和海口种群的虫体小于济宁和泗洪种群。结果提示中华稻蝗各种群已形成各自的地理适应机制，纬度梯度在其生活史的形成和发育中起着重要的作用。

Variation of embryonic diapause intensity and life-cycle pattern in five geographic populations of the Chinese rice grasshopper, Oxya chinensis (Orthoptera: Acridoidea: Catantopidae) from China

To investigate the geographic adaptation of the grasshopper, Oxya chinensis, populations of this grasshopper were collected in 5 localities ranging from 42.3°N to 20.0°N in China, and incidence of embryonic diapause, diapause intensity and adult body size were compared among the populations using their offsprings. The results indicated that different populations of the grasshopper displayed different patterns of response to photoperiod and temperature. The incidence of diapause was not influenced either by photoperiod or temperature in Tieling, Jining and Sihong populations, and their diapause rate was 100% under any conditions. Partial eggs entered diapause in the southern populations, i.e. Changsha and Haikou populations. A higher proportion of diapause eggs were produced at a short photoperiod than at a long photoperiod and the incubation temperature greatly influenced the induction of diapause in Haikou population, whereas the incidence of diapause in Changsha populations was only regulated by the incubation temperature of eggs. The egg diapause intensity was lowest in the Changsha and Haikou populations, followed by the Tieling population, and highest in the intermediate latitude populations, i.e. Jining and Sihong populations. In addition, diapause intensity increased as the original latitude decreased within the northern univoltine area. Adult body size showed a complicated pattern of variation along the latitudinal gradient. Significantly negative correlations between body size and latitude occurred within the northern populations; the body size of Changsha and Haikou populations, however, was smaller than that of Jining and Sihong populations. These results suggest that O. chinensis geographic populations have developed locality specific adaptations, and the latitudinal gradient appears to play an important role in shaping their life-cycle and development.