Ida Akiho, Karino Kenji
Department of Biology, Tokyo Gakugei University, 4-1-1 Koganei, Tokyo 184-8501, Japan.
Zoolog Sci. 2017 Dec;34(6):505-512. doi: 10.2108/zs170075.
In recent decades, variation in female preferences within a species has attracted considerable attention. However, how female individuals in most species change their mate preferences remain unclear. In this study, we examined the change in mate preferences in female individuals of the guppy, Poecilia reticulata. This was done by exposing naïve, virgin females to two male groups differing in the abundance of ornamented males over a period of seven days. The male-exposure treatment groups consisted of (1) primarily males with large orange spots and (2) primarily males with small orange spots. Following each treatment, we measured female preference for brightly colored males with large orange spots, using a pair of digitally modified male images differing in orange spot patterns. Our results indicated that the patterns of change in mate preferences differed between young and old females. After exposure to primarily males with large orange spots, young females were more attracted to the male images overall and showed a preference for the bright male image. Specifically, young females showed a stronger preference for the bright male image when they had been exposed to male groups in which the among-male difference in orange spot patterns was greater. However, in old females, both male-exposure treatments and order of the treatments affected their mate preferences. These results suggest that social components, i.e., both the abundance of ornamented males and the age structure of females in a population, influence the direction and intensity of sexual selection.
近几十年来，同一物种内雌性偏好的差异引起了广泛关注。然而，大多数物种中的雌性个体如何改变其配偶偏好仍不清楚。在本研究中，我们研究了孔雀鱼（Poecilia reticulata）雌性个体配偶偏好的变化。我们将未接触过雄性的处女雌性在七天时间内暴露于两组具有不同数量带饰雄性的雄性群体中。雄性暴露处理组包括：（1）主要是带有大橙色斑点的雄性，以及（2）主要是带有小橙色斑点的雄性。每次处理后，我们使用一对在橙色斑点图案上有所不同的数字修改过的雄性图像，来测量雌性对带有大橙色斑点的亮色雄性的偏好。我们的结果表明，年轻和年老雌性的配偶偏好变化模式有所不同。在暴露于主要是带有大橙色斑点的雄性群体后，年轻雌性总体上对雄性图像更感兴趣，并表现出对亮色雄性图像的偏好。具体而言，当年轻雌性暴露于橙色斑点图案雄性间差异更大的雄性群体时，她们对亮色雄性图像表现出更强的偏好。然而，对于年老雌性，雄性暴露处理和处理顺序都会影响她们的配偶偏好。这些结果表明，社会因素，即群体中带饰雄性的数量和雌性的年龄结构，会影响性选择的方向和强度。
