Bangham J, Chapman T, Smith H K, Partridge L
Department of Biology, Darwin Building, University College London, Gower Street, London WC1E 6BT, UK.
Proc Biol Sci. 2003 Mar 7;270(1514):523-30. doi: 10.1098/rspb.2002.2237.
Females as well as males can influence the outcome of sperm competition, and may do so through the anatomy of their reproductive tracts. Female Drosophila melanogaster store sperm in two morphologically distinct organs: a single seminal receptacle and, normally, two spermathecae. These organs have different temporal roles in sperm storage. To examine the association between sperm storage organ morphology and sperm competition, we used a mutant type of female with three spermathecae. Although the common measure of sperm competition, P(2), did not differ between females with two and three spermathecae, the pattern of sperm use over time indicated that female morphology did affect male reproductive success. The rate of offspring production by females with three spermathecae rose and fell more rapidly than by females with two spermathecae. If females remate or die before using up second male sperm, then second male reproductive success will be higher when they mate with females with three spermathecae. The results indicate that temporal patterns of sperm use as well as P(2) should be taken into account when measuring the outcome of sperm competition.
雌性和雄性都能影响精子竞争的结果，并且可能通过其生殖道的解剖结构来做到这一点。雌性黑腹果蝇将精子储存在两个形态不同的器官中：一个单一的受精囊，通常还有两个受精囊。这些器官在精子储存中具有不同的时间作用。为了研究精子储存器官形态与精子竞争之间的关联，我们使用了一种具有三个受精囊的突变型雌性果蝇。尽管精子竞争的常用指标P(2)在具有两个和三个受精囊的雌性之间没有差异，但随着时间推移的精子使用模式表明雌性形态确实会影响雄性的繁殖成功率。具有三个受精囊的雌性产生后代的速率比具有两个受精囊的雌性上升和下降得更快。如果雌性在耗尽第二个雄性的精子之前再次交配或死亡，那么当它们与具有三个受精囊的雌性交配时，第二个雄性的繁殖成功率会更高。结果表明，在衡量精子竞争的结果时，应同时考虑精子使用的时间模式以及P(2)。
