Otronen M
Department of Zoology, Uppsala University
Anim Behav. 1997 Jun;53(6):1233-40. doi: 10.1006/anbe.1996.0425.
To understand how individual differences in fertilization success arises in the fly Dryomyza anilisvariation in sperm precedence between and within males was studied. In D. anilisa mating consists of a copulation followed by tapping sequences during which the male taps the external genitalia of the female. These tapping sequences increase last male sperm precedence. Each male in the experiment was repeatedly mated with a set of females. In the first treatment, mating was interrupted after the male had an intromission. In the second treatment, the male was allowed to perform five tapping sequences after an intromission. In the third treatment, the male was allowed to perform an unlimited number of tapping sequences after an intromission until interrupted by female resistance. There were large differences between males in all three treatments as shown by the 95% confidence limits of the mean fertilization success. Repeatabilities of mating time and the number of tapping movements per tapping sequence were high indicating clear differences between males in these components of mating behaviour. Within individual males, the more tappings per sequence, the higher the fertilization success. In matings with an unlimited number of tapping sequences, fertilization success depended on female resistance. Within-male variation in fertilization success was higher in matings with an unlimited number of tapping sequences than in matings interrupted after a copulation. Several components of male mating behaviour thus contribute to the variation in sperm precedence in D. anilisFemale behaviour, in particular, resistance of tapping movements, can also increase variation in sperm precedence.
为了了解在果蝇Dryomyza anilis中受精成功率的个体差异是如何产生的，研究了雄性个体之间以及个体内部精子优先性的差异。在D. anilis中，交配包括一次交配以一系列轻敲动作，在此期间雄性轻敲雌性的外生殖器。这些轻敲动作增加了最后交配雄性的精子优先性。实验中的每只雄性都与一组雌性交配多次。在第一种处理中，在雄性插入后中断交配。在第二种处理中，允许雄性在插入后进行五次轻敲动作。在第三种处理中，允许雄性在插入后进行无限次数的轻敲动作，直到被雌性抗拒打断。如平均受精成功率的95%置信区间所示，在所有三种处理中雄性之间都存在很大差异。交配时间和每个轻敲序列的轻敲动作次数的重复性很高，表明雄性在这些交配行为组成部分上存在明显差异。在单个雄性内部，每个序列的轻敲次数越多，受精成功率越高。在有无限次数轻敲序列的交配中，受精成功率取决于雌性的抗拒。与交配后中断的交配相比，有无限次数轻敲序列的交配中雄性内部受精成功率的差异更大。因此，雄性交配行为的几个组成部分导致了D. anilis中精子优先性的差异。特别是雌性行为，即对轻敲动作的抗拒，也会增加精子优先性的差异。
