Geographical variation in male genitalia in Brachyphaphis episcopi (Poeciliidae):: is it sexually or naturally selected?
Geographical variation in male genitalia in Brachyphaphis episcopi (Poeciliidae):: is it sexually or naturally selected?
复制标题
DOI：
10.1034/j.1600-0706.2002.970108.x
复制
发表时间：
2002-04-01
期刊：
影响因子：
3.4
通讯作者：
Kelly, CD
中科院分区：
文献类型：
--
作者：
Jennions, MD;Kelly, CD
雄性花尾鱼用一种叫做生殖伪足的插入器官使雌性受精。在这里，我们报告的自然变化的生殖器大小内和12个种群之间的淡水鱼Brachyraphis episcopi（Poeciliidae）在巴拿马。我们发现，男性的网站有更多的掠食性鱼类，平均而言，一个相对较长的生殖伪足比男性居住的网站掠食性鱼类较少。生殖器的长度与特定网站的成年人的性别比和平均性别比更强烈的女性偏见，在网站有更多的捕食性鱼类。生殖器表现出较低的表型方差比平均的性选择性状，它通常表现为负异速生长。我们的研究结果与孔雀鱼的研究结果相似。这些研究结果的两个替代假设进行了讨论。首先，人口差异是性选择的结果。第二，它们是不同地点之间环境差异的附带后果。具体来说，较高的水流速度选择扩大鳍的大小和粗壮的机构在下游网站，食肉鱼类更常见。
Male poeciliid fishes inseminate females using an intromittent organ called the gonopodium. Here we report on natural variation in gonopodium size both within and between 12 populations of the freshwater fish Brachyrhaphis episcopi (Poeciliidae) in Panama. We show that males from sites with more predatory fish species have, on average, a relatively longer gonopodium than males inhabiting sites with fewer predatory fish. Gonopodium length was not correlated with the site-specific adult sex ratio and the average sex ratio was more strongly female biased at sites with more predatory fish. The gonopodium. exhibited lower phenotypic variance than the average for sexually selected traits and it generally showed negative allometry. Our results are similar to those reported for the guppy Poecilia reticulata. Two alternative hypotheses for these findings are discussed. First, that population differences are sexually selected. Second, that they are an incidental consequence of environmental differences between sites. Specifically, that higher water flow rates select for enlarged fin size and stockier bodies in downstream sites where predatory fish are more common.