Tilszer Magdalena, Antoszczyk Kinga, Sałek Natalia, Zajac Ewelina, Radwan Jacek
Institute of Environmental Sciences, Jagiellonian University, Cracow 30-387, Poland.
Evolution. 2006 Sep;60(9):1868-73. doi: 10.1554/06-060.1.
The experimental evolution under different levels of sexual conflict have been used to demonstrate antagonistic coevolution in muscids, but among other taxa a similar approach has not been employed. Here, we describe the results of 37 generations of evolution under either experimentally enforced monogamy or polygamy in the bulb mite Rhizoglyphus robini. Three replicates were maintained for each treatment. Monogamy makes male and female interests congruent; thus selection is expected to decrease harmfulness of males to their partners. Our results were consistent with this prediction in that females from monogamous lines achieved lower fecundity when housed with males from polygamous lines. Fecundity of polygamous females was not affected by mating system under which their partners evolved, which suggests that they were more resistant to male-induced harm. As predicted by the antagonistic coevolution hypothesis, the decrease in harmfulness of monogamous males was accompanied by a decline in reproductive competitiveness. In contrast, female fecundity and embryonic viability, which were not expected to be correlated with male harmfulness, did not differ between monogamous and polygamous lines. None of the fitness components assayed differed between individuals obtained from crosses between parents from the same line and those obtained from crosses between parents from different lines within the same mating system. This indicates that inbreeding depression did not confound our results. However, interpretation of our results is complicated by the fact that both males and females from monogamous lines evolved smaller body size compared to individuals from polygamous lines. Although a decrease in reproductive performance of males from monogamous lines was still significant when body size was taken into account, we were not able to separate the effects of male body size and mating system in their influence on fecundity of their female partners.
在不同性冲突水平下的实验性进化已被用于证明蝇类中的对抗性协同进化，但在其他分类群中尚未采用类似方法。在此，我们描述了在实验强制实行一夫一妻制或一夫多妻制条件下，罗宾根螨（Rhizoglyphus robini）经过37代进化的结果。每种处理维持三个重复样本。一夫一妻制使雄性和雌性的利益一致；因此预计选择会降低雄性对其配偶的伤害性。我们的结果与这一预测一致，即当与来自一夫多妻制品系的雄性饲养在一起时，来自一夫一妻制品系的雌性繁殖力较低。一夫多妻制雌性的繁殖力不受其配偶所经历交配系统的影响，这表明它们对雄性造成的伤害更具抵抗力。正如对抗性协同进化假说所预测的，一夫一妻制雄性伤害性的降低伴随着生殖竞争力的下降。相比之下，预计与雄性伤害性无关的雌性繁殖力和胚胎活力，在一夫一妻制和一夫多妻制品系之间并无差异。在同一交配系统内，来自同品系亲本杂交的个体与来自不同品系亲本杂交的个体之间，所检测的任何适合度成分均无差异。这表明近亲繁殖衰退并未混淆我们的结果。然而，由于一夫一妻制品系的雄性和雌性与一夫多妻制品系的个体相比，体型进化得更小，这一事实使我们对结果的解释变得复杂。尽管在考虑体型因素时，一夫一妻制品系雄性繁殖性能的下降仍然显著，但我们无法区分雄性体型和交配系统对其雌性配偶繁殖力的影响。
