营养对雄性短翅鸣螽繁殖投资的影响

螽斯交配时产生精包,精包由精护与精荚组成。交配后雌性咬食精护。吃完精护后将精荚吃掉。精护是螽斯的一种繁殖投资方式。我们研究营养对雄性螽斯投资的影响。结果表明：⑴螽斯首次交配后产生的精包、精护、精夹的鲜重以及精荚、精护干重组间差异显著,高营养组雄性投资显著高于其它组;⑵营养缺乏时,有效性比偏雌。本研究支持性差异理论以及Ｇｗｙｎｎｅ（１９９０）和Ｓｉｍｍｏｎｓ（１９９５）的工作;⑶精荚和精护重量与雄性

EFFECTS OF NUTRITION ON THE REPRODUCTIVE INVESTMENT IN GAMPSOCLEIS GRATIOSA MALES

Spermatophylax appeared during copulation is a form of reproductive investments by male insects. We studied how nutrition status affects the investment in Gampsocleis gratiosa.Our experiments demonstrated:(1)The mass of wet spermatophore,wet spermatophylax,wet and dried ampulla, dried spermatophylax, which appeared during the first copulation, were significantly diffeent among different treatments. These results indicated that males in good nutrition status or of large size have advantage in female's cryptic choice.(2) There were less sexually active males than females when food is in short supply, which resulted in femalebiased operational sex ratio, supporting the sexdifference theory proposed by Trivers (1972) and the work by Gwynne (1990) and Simmons (1995).(3)Ampulla mass and spermatophylax mass were positively correlated to male hody mass, spermatophylax mass was positively correlated to ampulla mass, suggesting that the role of spermatophylax was, at least,to guarantee fertilaization.(4)The investment in ampulla (AM/BM) was negatively correlated to the investment in spermatophylax.(5)Fooddeprived males invested significantly higher in ampulla than that by high nutrition males, (6)Water contents were not significantly different between the treatments. Results(3),(4),(5) and (6) demonstrated that when limited by the food,males give their priority to the investment in sperms, to guarantee their reproductive success in female's cryptic choice and sperm competition.