Sexual selection and the fitness consequences of male body size in the seed beetle Stator limbatus
Sexual selection and the fitness consequences of male body size in the seed beetle
Stator limbatus
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种子甲虫定子边缘的性选择和雄性体型的适应性影响
DOI：
10.1006/anbe.1997.0622
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发表时间：
1998
期刊：
影响因子：
2.5
通讯作者：
C. Fox
中科院分区：
文献类型：
--
作者：
U. Savalli;C. Fox
我们研究了种子甲虫实验室种群中雄性体型大小的性选择，以及与体型较大的雄性交配对雌性的适应性影响。较大的雄性比较小的雄性产生更多的射精。雄性和雌性都因繁殖而体重减轻，体型较大的雄性比体型较小的雄性体重减轻更多。雄性体重减轻量与雌性生育力的相关性与雌性体重减轻量的相关性一样高。同样，男性和女性体重与女性生育力的相关性也同样高。这些结果表明，雄性可能通过射精中转移的营养物质，对雌性的生育能力做出了重大贡献。因此，繁殖力选择应该有利于雄性和雌性体型较大的动物。我们发现，当未交配的雌性只与一只雄性在一起时，它们对体型较大的雄性没有偏好，但当同时与两只雄性在一起时，雌性更有可能与较大的雄性交配。这一结果与相对的女性选择或男性间竞争一致，尽管没有观察到男性间竞争的迹象。与体型较小的雄性交配的雌性比首次与体型较大的雄性交配的雌性重新交配得更快。首次与非处女雄性交配的雌性也比首次与处女雄性交配的雌性更有可能重新交配，这表明雌性重新交配是为了获得额外的精子或营养，而不仅仅是作为一种择偶形式。除了择偶和雄性之间的竞争可能带来的好处外，体型较大的雄性还通过减少精子竞争获得了交配优势。这种巨大的雄性优势，加上雄性和雌性的繁殖力选择，可能是该物种中雄性体型大于雌性的原因。版权所有 1998 动物行为研究协会。
We examined sexual selection on male body size in a laboratory population of the seed beetle, Stator limbatus, and the fitness consequences to females of mating with larger males. Large males produced larger ejaculates than small males. Both males and females lost body weight as a consequence of breeding, and large males lost more weight than small males. The amount of weight lost by males correlated as highly with female fecundity as did the amount of weight lost by females. Similarly, male and female body weight correlated equally highly with female fecundity. These results indicate that males make substantial contributions to female fecundity, probably through nutrients transferred in their ejaculate. As a consequence, fecundity selection should favour large body size in both males and females. We found no preference for large males when virgin females were presented with only one male, but when presented with two males simultaneously, females were more likely to mate with the larger male. This result is consistent with relative female choice or male-male competition, although no indications of male-male competition were observed. Females that mated with small males re-mated sooner than females that first mated with large males. Females that first mated with a non-virgin male were also more likely to re-mate than females that first mated with a virgin male, suggesting that females re-mate to obtain additional sperm or nutrients and not just as a form of mate choice. In addition to the possible benefits from mate choice and male-male competition, large males gain a mating advantage through reduced sperm competition. This large male advantage, combined with fecundity selection on males as well as females, may account for males being larger than females in this species.Copyright 1998 The Association for the Study of Animal Behaviour.