Data from: Sex-specific responses to sexual familiarity, and the role of olfaction in Drosophila

Studies of mating preferences have largely neglected the potential effects of individuals encountering their previous mates (‘directly sexually familiar’), or new mates that share similarities to previous mates, e.g. from the same family and/or environment (‘phenotypically sexually familiar’). Here, we show that male and female Drosophila melanogaster respond to the direct and phenotypic sexual familiarity of potential mates in fundamentally different ways. We exposed a single focal male or female to two potential partners. In the first experiment, one potential partner was novel (not previously encountered) and one was directly familiar (their previous mate); in the second experiment, one potential partner was novel (unrelated, and from a different environment from the previous mate) and one was phenotypically familiar (from the same family and rearing environment as the previous mate). We found that males preferentially courted novel females over directly or phenotypically familiar females. In contrast, females displayed a weak preference for directly and phenotypically familiar males over novel males. Sex-specific responses to the familiarity of potential mates were significantly weaker or absent in Orco1 mutants, which lack a co-receptor essential for olfaction, indicating a role for olfactory cues in mate choice over novelty. Collectively, our results show that direct and phenotypic sexual familiarity is detected through olfactory cues and play an important role in sex-specific sexual behaviour.

择偶偏好相关研究大多忽略了两类潜在影响：其一为个体遭遇前任配偶所产生的效应，即直接性熟悉（directly sexually familiar）个体；其二为与前任配偶存在相似特征的新配偶所带来的效应，例如来自同一家族或饲养环境的个体，即表型性熟悉（phenotypically sexually familiar）个体。
本研究以黑腹果蝇（Drosophila melanogaster）为实验对象，发现雌雄个体对潜在配偶的直接性熟悉与表型性熟悉的响应模式存在本质差异。
我们将单只目标雌雄果蝇分别置于两只潜在配偶共存的环境中。第一项实验中，一只潜在配偶为陌生个体（未提前与目标个体接触过），另一只为直接性熟悉个体（即目标个体的前任配偶）；第二项实验中，一只潜在配偶为陌生个体（与前任无亲缘关系且来自不同饲养环境），另一只为表型性熟悉个体（与前任来自同一家族及饲养环境）。
研究结果显示，相较于直接性熟悉或表型性熟悉的雌性果蝇，雄性果蝇会优先向陌生雌性求偶；与之相反，雌性果蝇对陌生雄性的偏好较弱，更倾向于选择直接性熟悉或表型性熟悉的雄性个体。
在缺失嗅觉必需共受体的Orco1突变体中，针对潜在配偶熟悉度的性别特异性响应显著减弱甚至消失，这表明嗅觉信号在基于新颖性的配偶选择中发挥了重要作用。
综上，本研究结果表明，个体可通过嗅觉信号识别直接性熟悉与表型性熟悉的配偶，且该识别过程在性别特异性的求偶行为中扮演关键角色。