Intrasexual competition and mate choice in assassin bugs with uniparental male and female care
Intrasexual competition and mate choice in assassin bugs with uniparental male and female care
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单亲雄性和雌性照顾下刺客虫的性内竞争和配偶选择
DOI：
10.1016/j.anbehav.2004.03.009
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发表时间：
2005
期刊：
影响因子：
2.5
通讯作者：
A. Manica
中科院分区：
文献类型：
--
作者：
L. K. Thomas;A. Manica
父性关怀有可能导致女性偏见的手术性别比例和性别角色颠倒。虽然这个问题在鱼类中已经被反复研究过，但我们提出了第一个关于昆虫的研究。我们调查了两种刺客昆虫：三翼犀牛和卡梅利塔，前者表现出雄性对卵的照顾，后者表现出雌性对卵的照顾。在这两个物种中，雄性的潜在生殖率都超过了雌性。由于种群性别比是无偏见的，并且两性之间的死亡率没有差异，我们预测，在两个物种中，可操作的性别比将偏向于男性，因此男性将是更具竞争性的性别。野外和实验室的观察证实了这一预测，在这两个物种中，雄性都在争夺雌性。在三齿轮虫中，雄性也会争夺卵子的所有权，而雌性根据卵子的所有权对雄性进行歧视。然而，挑剔并不局限于三刺大头翁的雌性。观察表明，雄性三叉戟根据体重对雌性进行区分：较重的雌性在交配后骑马的一段时间内由雄性守卫更长时间，这些雌性可能更早产卵。我们认为交配后骑马的主要功能是防止雌性与同种动物交配，从而减少精子竞争的可能性。这一行为也可能是男性护理演变的一个重要前提。
Paternal care has the potential to lead to female-biased operational sex ratios and sex role reversal. Whereas this issue has been repeatedly investigated in fish, we present the first study on insects. We investigated two species of assassin bug: Rhinocoris tristis, which shows male care of eggs, and Rhinocoris carmelita, which shows female care of eggs. In both species, the potential reproductive rate of males exceeded that of females. Since the population sex ratio was unbiased and there was no difference in mortality rates between the sexes, we predicted that the operational sex ratio would be skewed in favour of males in both species and thus males would be the more competitive sex. Field and laboratory observations upheld this prediction, with males competing for females in both species. In R. tristis, males also competed for ownership of eggs, whereas females discriminated between males according to ownership of eggs. However, choosiness was not restricted to females in R. tristis. Observations suggested that R. tristis males discriminated between females according to their weight: heavier females, which were likely to oviposit sooner, were guarded for longer by males in a period of postcopulatory riding. We suggest that the primary function of postcopulatory riding is to prevent females from mating with conspecifics, thus reducing the possibility of sperm competition. This behaviour might also be an important prerequisite for the evolution of male care.