Civetta A, Clark A G
Department of Biology, Pennsylvania State University, University Park, PA 16802, USA.
Proc Natl Acad Sci U S A. 2000 Nov 21;97(24):13162-5. doi: 10.1073/pnas.230305397.
Adaptations in one sex may impair fitness in the opposite sex. Experiments with Drosophila melanogaster have shown that seminal fluid from the male accessory gland triggers a series of postmating responses in the female, including increased egg laying rate and lower remating propensity, but that accessory gland proteins also increase female death rate. Here, we tested the relationships among the longevity of females mated to males from 51 chromosome-extracted D. melanogaster lines, male-mating ability, and sperm-competitive ability. We found significant differences in longevity of females mated to males of different genotypes, and all mated females showed a higher death rate than control virgin females shortly after mating. Both the age-independent mortality parameter (the intercept of the female's survival function) and the slope of the mortality rate curve were significantly correlated with the proportion of progeny sired by the first male to mate relative to tester males (sperm-defense ability, P1). No significant correlation was found between the proportion of progeny sired by the second-mating male relative to tester males (sperm-offense ability, P2) and any mortality parameter. Our results support the hypothesis of a tradeoff between defensive sperm-competitive ability of males and life-history parameters of mated females.
一个性别的适应性变化可能会损害另一性别的健康状况。对黑腹果蝇的实验表明，雄性附腺分泌的精液会引发雌性一系列交配后的反应，包括产卵率增加和再次交配倾向降低，但附腺蛋白也会提高雌性死亡率。在此，我们测试了与来自51个染色体提取的黑腹果蝇品系的雄性交配的雌性的寿命、雄性交配能力和精子竞争能力之间的关系。我们发现，与不同基因型雄性交配的雌性在寿命上存在显著差异，并且所有交配后的雌性在交配后不久都显示出比未交配的对照雌性更高的死亡率。与年龄无关的死亡率参数（雌性生存函数的截距）和死亡率曲线的斜率都与第一个交配雄性相对于测试雄性所产子代的比例（精子防御能力，P1）显著相关。第二个交配雄性相对于测试雄性所产子代的比例（精子进攻能力，P2）与任何死亡率参数之间均未发现显著相关性。我们的结果支持了这样一种假设，即雄性的防御性精子竞争能力与交配后雌性的生活史参数之间存在权衡。
