Jayaweera Anuradhi, Barry Katherine L
Department of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia.
PLoS One. 2015 May 13;10(5):e0124209. doi: 10.1371/journal.pone.0124209. eCollection 2015.
Strategic ejaculation is a behavioural strategy shown by many animals as a response to sperm competition and/or as a potential mechanism of cryptic male choice. Males invest more mating resources when the risk of sperm competition increases or they invest more in high quality females to maximize their reproductive output. We tested this hypothesis in the false garden mantid Pseudomantis albofimbriata, where females are capable of multiply mating and body condition is an indicator of potential reproductive fitness. We predicted male mantids would ejaculate strategically by allocating more sperm to high quality females. To determine if and how males alter their ejaculate in response to mate quality, we manipulated female food quantity so that females were either in good condition with many eggs (i.e. high quality) or poor condition with few eggs (i.e. low quality). Half of the females from each treatment were used in mating trials in which transferred sperm was counted before fertilisation occurred and the other half of females were used in mating trials where fertilisation occurred and ootheca mass and total eggs in the ootheca were recorded. Opposed to our predictions, the total number of sperm and the proportion of viable sperm transferred did not vary significantly between female treatments. Male reproductive success was entirely dependent on female quality/fecundity, rather than on the number of sperm transferred. These results suggest that female quality is not a major factor influencing postcopulatory male mating strategies in P. albofimbriata, and that sperm number has little effect on male reproductive success in a single mating scenario.
策略性射精是许多动物所表现出的一种行为策略，作为对精子竞争的一种反应和/或作为隐秘雄性选择的一种潜在机制。当精子竞争风险增加时，雄性会投入更多的交配资源，或者它们会在高质量雌性身上投入更多，以最大化其生殖产出。我们在伪花园螳螂（Pseudomantis albofimbriata）中对这一假设进行了测试，在这种螳螂中，雌性能够多次交配，身体状况是潜在生殖适合度的一个指标。我们预测雄性螳螂会通过向高质量雌性分配更多精子来进行策略性射精。为了确定雄性是否以及如何根据配偶质量改变其射精情况，我们控制了雌性的食物量，使雌性要么处于有许多卵的良好状态（即高质量），要么处于卵少的较差状态（即低质量）。每种处理的一半雌性用于交配试验，在受精发生前对转移的精子进行计数，另一半雌性用于交配试验，记录受精发生时的卵鞘质量和卵鞘中的总卵数。与我们的预测相反，雌性处理之间转移的精子总数和存活精子的比例没有显著差异。雄性的繁殖成功完全取决于雌性的质量/繁殖力，而不是转移的精子数量。这些结果表明，雌性质量不是影响伪花园螳螂交配后雄性交配策略的主要因素，并且在单一交配情况下，精子数量对雄性繁殖成功的影响很小。
