Data from: No evidence for postcopulatory inbreeding avoidance in Drosophila melanogaster

Selection to avoid inbreeding is predicted to vary across species due to differences in population structure and reproductive biology. Over the past decade, there have been numerous investigations of postcopulatory inbreeding avoidance, a phenomenon that first requires discrimination of mate (or sperm) relatedness and then requires mechanisms of male ejaculate tailoring and/or cryptic female choice to avoid kin. The number of studies that have found a negative association between male-female genetic relatedness and competitive fertilization success is roughly equal to the number of studies that have not found such a relationship. In the former case, the underlying mechanisms are largely unknown. The present study was undertaken to verify and expand upon a previous report of postcopulatory inbreeding avoidance in D. melanogaster, as well as to resolve underlying mechanisms of inbreeding avoidance using transgenic flies that express a sperm head-specific fluorescent tag. However, siblings did not have a lower fertilization success as compared to unrelated males in either the first (P1) or second (P2) mate role in sperm competition with a standard unrelated competitor male in our study population of D. melanogaster. Analyses of mating latency, copulation duration, egg production rate and remating interval further revealed no evidence for inbreeding avoidance.

由于种群结构与生殖生物学特征的差异，不同物种间避免近交的选择压力预计存在差异。过去十年间，已有大量研究聚焦于交配后近交回避（postcopulatory inbreeding avoidance）：这一现象首先需要对配偶（或精子）的亲缘关系进行辨别，随后需借助雄性射精调控机制或隐性雌性选择（cryptic female choice）等途径实现近亲规避。发现雌雄个体遗传亲缘关系与竞争性受精成功率呈负相关的研究，与未发现此类关联的研究数量大致相当。在观测到负相关关联的研究中，其背后的潜在机制大多尚未明确。本研究旨在验证并拓展此前关于黑腹果蝇（D. melanogaster）交配后近交回避的研究报道，并借助表达精子头部特异性荧光标记的转基因果蝇，解析近交回避的潜在机制。然而，在本研究的黑腹果蝇种群中，无论是以第一配偶角色（P1）还是第二配偶角色（P2）的身份参与与标准无关竞争者雄性的精子竞争，同胞雄性的受精成功率均未低于无关雄性。对交配潜伏期、交尾持续时间、产卵速率以及再交配间隔的分析，同样未发现存在近交回避的迹象。