Effects of condition and sperm competition risk on sperm allocation and storage in neriid flies

Ejaculate traits can be sexually selected and often exhibit heightened condition-dependence. However, the influence of sperm competition risk in tandem with condition-dependent ejaculate allocation strategies is relatively unstudied. Because ejaculates are costly to produce, high-condition males may be expected to invest more in ejaculates when sperm competition risk is greater. We examined the condition-dependence of ejaculate size by manipulating nutrient concentration in the juvenile (larval) diet of the neriid fly Telostylinus angusticollis. Using a fully factorial design we also examined the effects of perceived sperm competition risk (manipulated by allowing males to mate first or second) on the quantity of ejaculate transferred and stored in the three spermathecae of the female reproductive tract. To differentiate male ejaculates, we fed males non-toxic rhodamine fluorophores (which bind to proteins in the body) prior to mating, labelling their sperm red or green. We found that h...

射精特征可受性选择作用，且常表现出更强的状态依赖性（condition-dependence）。然而，精子竞争风险与状态依赖性射精分配策略协同产生的影响尚缺乏深入研究。由于射精产物的生成成本高昂，当精子竞争风险升高时，高状态雄性可能会在射精上投入更多资源。我们通过操控尼利蝇 Telostylinus angusticollis 幼体（幼虫期）饮食中的营养浓度，探究了射精量的状态依赖性。我们采用完全析因设计（fully factorial design），还探究了感知到的精子竞争风险（通过让雄性优先或次优交配来操控）对转移并储存在雌性生殖道三个受精囊（spermathecae）中的射精量的影响。为区分不同雄性的射精产物，我们在交配前给雄性喂食无毒的罗丹明荧光团（rhodamine fluorophores）（可与体内蛋白质结合），将其精子标记为红色或绿色。我们发现...