COPULATORY PLUGS, RESTRICTED MATING OPPORTUNITIES AND REPRODUCTIVE COMPETITION AMONG MALE GARTER SNAKES
COPULATORY PLUGS, RESTRICTED MATING OPPORTUNITIES AND REPRODUCTIVE COMPETITION AMONG MALE GARTER SNAKES
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DOI：
10.1038/267345a0
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发表时间：
1977-01-01
期刊：
影响因子：
64.8
通讯作者：
DEVINE, MC
中科院分区：
文献类型：
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作者：
DEVINE, MC
一个特定物种的雄性之间对雌性的生殖竞争可以有多种形式，其中一些形式(如交配插头)可能会限制雄性的交配机会，并加剧对现有雌性的竞争。我研究了两种吊袜带蛇(Thamnopits sirtalisand T.Butleri)在外地工作了5年。它们没有表现出配对关系、父亲对后代的照顾、领土归属或性内战斗。这种交配系统中的性别选择应该有利于那些竞相寻找、追求和交配最多数量的雌性的雄性1。然而，我在同一时期和同一地区观察到了许多孤独的雌性Thamnophis，在这些区域，其他雌性正在积极地追求，通常是几个雄性。我以前观察到，任何新近交配的雌性扁桃体的前泄殖腔都有一个交配塞子，它阻塞了输卵管的开口。这个塞子显然是由交配的雄性在精子移植后形成的。我把这解释为一种性内竞争的形式，在这种竞争中，成功交配的雄性使其他雄性暂时无法获得雌性，并降低了多次受精的可能性。一些报告3，4表明多次受精是可能的。我在这里展示了来自野外的证据，即雄性吊带蛇通过交配插头识别雌性，并表现得就像这些雌性是不可获得的。
REPRODUCTIVE competition for females among males of a given species can take many forms, some of which (like mating plugs) may place constraints on the mating opportunities of males and intensify competition for available females. I have studied the reproductive behaviour of two garter snake species (Thamnophis sirtalisandT. butleri) in the field for 5 years. They do not exhibit pair-bonding, paternal care of offspring, territoriality, or intrasexual combat. Sexual selection in this mating system should favour males which compete to locate, court and mate with the maximum number of females1. Yet I have observed numerous solitary femaleThamnophiswithin the same time periods and areas in which other females were being vigorously courted, often by several males. I have previously observed that the anterior cloaca of any recently mated femaleThamnophiscontains a copulatory plug which occludes the oviductal orifices2. The plug evidently is formed by the copulating male after sperm transfer. I interpreted this as a form of intrasexual competition in which the successfully copulating male makes the female temporarily unavailable to other males and reduces the likelihood of multiple inseminations. Some reports3,4indicate that multiple inseminations are possible. I present here evidence from the field that male garter snakes recognise females with a copulatory plug and behave as if these females were unavailable.