Experimental evolution under hyper-promiscuity in Drosophila melanogaster.
Experimental evolution under hyper-promiscuity in Drosophila melanogaster.
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DOI：
10.1186/s12862-016-0699-8
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发表时间：
2016-06-16
影响因子：
3.4
通讯作者：
Wigby S
中科院分区：
文献类型：
--
作者：
Perry JC;Joag R;Hosken DJ;Wedell N;Radwan J;Wigby S
个体一生中交配的伴侣数量是交配系统的一个决定性特征，而交配数量的变化被认为是性进化的主要驱动力。尽管之前的研究已经调查了配偶数量减少的进化后果，但我们对增加配偶数量的成本和收益知之甚少。在这里，我们利用果蝇交配频率的基因操作来创建一种新颖的、高度混杂的交配系统。我们生成了黑腹果蝇种群，其中果蝇缺乏性肽受体 (SPR) 基因（导致 SPR 雌性交配更频繁）和基因匹配的对照种群，并让它们进化了 55 代。在这个实验进化过程中的几个时间点，我们分析了行为、形态和转录生殖表型，这些表型预计会随着种群交配频率的增加而进化。我们发现，来自高交配频率 SPR 群体的雄性进化出抑制配偶接受能力的能力下降，并缩短了交配持续时间，这与精子竞争加剧导致永交投资减少的预测一致。出乎意料的是，SPR群体的雄性也进化出了性肽（SP）基因表达的微弱增加。相对于对照组，SPR-群体的雄性最初（即在实验进化之前）表现出更频繁的求爱和更快的交配时间，但随着进化时间的推移，这些差异减少或逆转。为了响应实验上增加的交配频率，SPR-雄性进化出与每次交配时雄性交配后投入减少和整体交配前表现下降一致的行为反应。 SP 基因表达增加的趋势可能与 SP 蛋白两个结构域的功能差异有关。我们的研究强调了动物社会和性环境的基因操纵与实验进化相结合的效用。本文的在线版本 (doi:10.1186/s12862-016-0699-8) 包含补充材料，可供授权用户使用。
The number of partners that individuals mate with over their lifetime is a defining feature of mating systems, and variation in mate number is thought to be a major driver of sexual evolution. Although previous research has investigated the evolutionary consequences of reductions in the number of mates, we know little about the costs and benefits of increased numbers of mates. Here, we use a genetic manipulation of mating frequency in Drosophila melanogaster to create a novel, highly promiscuous mating system. We generated D. melanogaster populations in which flies were deficient for the sex peptide receptor (SPR) gene – resulting in SPR- females that mated more frequently – and genetically-matched control populations, and allowed them to evolve for 55 generations. At several time-points during this experimental evolution, we assayed behavioural, morphological and transcriptional reproductive phenotypes expected to evolve in response to increased population mating frequencies. We found that males from the high mating frequency SPR- populations evolved decreased ability to inhibit the receptivity of their mates and decreased copulation duration, in line with predictions of decreased per-mating investment with increased sperm competition. Unexpectedly, SPR- population males also evolved weakly increased sex peptide (SP) gene expression. Males from SPR- populations initially (i.e., before experimental evolution) exhibited more frequent courtship and faster time until mating relative to controls, but over evolutionary time these differences diminished or reversed. In response to experimentally increased mating frequency, SPR- males evolved behavioural responses consistent with decreased male post-copulatory investment at each mating and decreased overall pre-copulatory performance. The trend towards increased SP gene expression might plausibly relate to functional differences in the two domains of the SP protein. Our study highlights the utility of genetic manipulations of animal social and sexual environments coupled with experimental evolution. The online version of this article (doi:10.1186/s12862-016-0699-8) contains supplementary material, which is available to authorized users.