SPATIAL VARIATION IN SELECTIVE REGIMES - SEXUAL SELECTION IN THE WATER STRIDER GERRIS-ODONTOGASTER
SPATIAL VARIATION IN SELECTIVE REGIMES - SEXUAL SELECTION IN THE WATER STRIDER GERRIS-ODONTOGASTER
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DOI：
10.1111/j.1558-5646.1992.tb00609.x
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发表时间：
1992-08-01
期刊：
影响因子：
3.3
通讯作者：
ARNQVIST, G
中科院分区：
文献类型：
--
作者：
ARNQVIST, G
自然种群中表型选择的研究通常只是简单地检测选择。本研究采用了一种更机械的方法，将水黾自然种群的性选择制度与先验的选择预测进行了比较，该预测是基于许多先前的野外和实验室对选择行为机制的研究。在这个物种中，雌性普遍不愿交配，这使得两性间选择能够征服雄性中不愿交配的雌性。随着人口密度的增加，雌性不愿交配的意愿会减少，这表明在高密度的人口中，性选择应该更弱。研究了种群密度差异较大的3个不同种群。包括寄生虫负荷、体重、体型和雄性腹部过程长度在内的许多性状都经历了显著的性选择。被调查群体对被测性状的选择总强度和对单个性状的选择形式存在较大差异。总体而言，密度最高的种群中雄虫的抓握能力选择最弱。这种模式归因于与密度相关的雌性交配行为的改变。雄性抓取能力的选择，反映在雄性腹部过程长度的选择上，在高密度的种群中，不情愿的雌性更容易被制服。此外，研究群体在男性腹突长度的平均表型和表型方差上存在显著差异。这表明，种群间的选择差异可能导致雄性腹部过程长度的局部适应，而基因流动可能有助于维持这一性状的高度遗传变异。进一步指出，在量化和理解自然种群选择的时空变化方面，应作出更多的经验努力，因为这可能提供有关度量性状的局部适应的普遍程度和选择机制的信息。
Studies of phenotypic selection in natural populations are often concerned with simply detecting selection. In adopting a more mechanistic approach, this study compares the sexual selection regimes in natural populations of the water strider Gerris odontogaster with a priori predictions of selection, based on a number of previous field and laboratory studies of the behavioral mechanisms of selection. In this species, a general reluctance of females to mate allows for intersexual selection for ability to subdue reluctant females in males. Female reluctance to mate has been shown to decrease with increasing population density, suggesting that sexual selection should be weaker in high density populations. Three different populations with large differences in population density were studied. A number of traits including parasite load, body mass, body size and male abdominal process length were found to experience significant sexual selection. The investigated populations differed considerably with regard to the total strength of selection on the measured traits and the form of selection on single traits. In general, males in the population with the highest density experienced the weakest selection for grasping ability. This pattern is ascribed to density-related alterations of female mating behavior. Selection for male grasping ability, as reflected by selection on male abdominal process length, is reduced in high-density populations where reluctant females are more easily subdued. Further, the studied populations differed significantly in mean phenotype and phenotypic variance for male abdominal process length. It is suggested that interpopulational differences in selective regimes may generate local adaptations with respect to male abdominal process length, and that gene flow may contribute to the maintenance of the high genetic variation in this trait. It is further suggested that more empirical effort should be made in quantifying and understanding spatial and temporal variation in selection in natural populations, since this may provide information on the prevalence of local adaptations in metric traits and on the mechanisms of selection.