Sato Aya, Shimoichi Arisa, Karino Kenji
Department of Biology, Tokyo Gakugei University, 4-1-1 Nukui-kita, Koganei, Tokyo 184-8501, Japan.
Zoolog Sci. 2011 Feb;28(2):98-104. doi: 10.2108/zsj.28.98.
In some animals, females are often compelled to mate with less desirable males due to the males' alternative mating tactics. Male guppies, Poecilia reticulata, exhibit courtship displays and cooperatively copulate with females. However, they also exhibit sneaking behaviors and coercively copulate with females. To examine the consequences of these two mating patterns, we investigated the influence of copulation type, i.e., cooperative or coercive, on parturition and brood size of females. A single female was allowed to freely contact and copulate with a single male only once. Males that cooperatively copulated with females had larger orange spot areas (an important criterion of female mate choice) than males that copulated coercively. Most females that were coerced into copulation did not give birth to offspring within 100 days after mating. The probability of parturition was high when females copulated cooperatively, and when their mates exhibited frequent postcopulatory jerking behavior. However, the results suggest that copulation type did not affect brood size. Brood size was positively influenced by both female body size and male orange spot area. These results suggest that parturient success is low when females are coerced into mating by less desirable males, whereas brood size is independent of copulation type.
在一些动物中，由于雄性的另类交配策略，雌性常常被迫与不那么理想的雄性交配。雄性孔雀鱼（孔雀花鳉）会展示求偶行为并与雌性交配。然而，它们也会表现出偷配行为并强行与雌性交配。为了研究这两种交配模式的后果，我们调查了交配类型（即合作式或强制式）对雌性分娩和产仔数的影响。只允许一只雌性与一只雄性自由接触并交配一次。与雌性交配的雄性中，采用合作式交配的雄性比采用强制式交配的雄性具有更大的橙色斑点面积（雌性择偶的一个重要标准）。大多数被迫交配的雌性在交配后100天内没有产仔。当雌性进行合作式交配且其配偶表现出频繁的交配后抽搐行为时，分娩的概率较高。然而，结果表明交配类型并不影响产仔数。产仔数受到雌性体型和雄性橙色斑点面积的正向影响。这些结果表明，当雌性被不那么理想的雄性强迫交配时，分娩成功率较低，而产仔数与交配类型无关。
