Adaptive significance of sperm competition in orthopteran insects having multiple mating system.

本文研究了两种具有多交配系统的直翅目昆虫的交配选择和交配对雌性的益处，特别是精子竞争，并测定了宽额负蝗的个体大小和年龄对交配频率的影响。中等体型的雌性比较小或较大体型的雌性交配更频繁。雌体大小与羽化季节有关，即羽化日期越晚，雌体越小。因此，在出现后一个季节（9月）的女性，观察到的交配频率的大小依赖性增加。雌虫取食的是一种粘性物质，这种物质是由雄虫的后鼻孔腺分泌的。本文研究了后鼻孔分泌物取食对雌虫产卵量的影响及其与多交配系统的关系。多次提供分泌物的雌虫的生殖力显著低于单次交配的雌虫。此外，40日龄后鼻孔分泌物的消耗水平与卵巢中的成熟卵子呈负相关。这种现象的适应意义是一个相当有趣的问题，在未来解决。

Two orhthopteran insects having multiple mating system were studied on the view points of the mate choice and the benefit of mating for the female with special reference to sperm competition.In Atractomorpha lata, the effects of body size and age on the mating frequency were measured. Middle size of females mate more frequently than smaller or larger sizes. Female body size was correlated with emerging season, namely the latter date of emergence, the smaller females appeared. Therefore, in the females emerging latter season (in September), a size dependent increase of mating frequency was observed. Also, the positive correlations were observed between age and mating frequency in both female and male.The females Truljalia hibinonis feed a sticky material, which secreted from male metanotal gland. The effect of metanotal secretion feeding on female egg production was examined with the relation to the multiple mating system. The fecundity of females offered the secretion multiply was significantly lower than that of females of single mating. Moreover, there was a negative correlation between the consuming level of metanotal secretion and mature eggs in ovary at 40 days old. The adaptive significance of this phenomenon is a quite interesting problem to solve in future.