Interspecific mating normally decreases female fitness. In many species, females avoid heterospecific males innately or by imprinting on their parents. Alternatively, adult females could learn to discriminate against heterospecific males after exposure to such males. For example, Syrian hamster (Mesocricetus auratus) females learn to discriminate between conspecific males and Turkish hamster (M. brandti) males during adulthood by exposure to males of both species. Adult females not previously exposed to Turkish hamster males will mate similarly with conspecific and heterospecific males. However, in a previous study we showed that exposure to a heterospecific male and a conspecific male for 8 days led to mating avoidance and aggression towards the heterospecific male. Here we conducted two experiments to investigate how much exposure to the heterospecific male was required for females to avoid mating with the heterospecific male (Experiment 1) and how long that avoidance lasted in the absence of continuous exposure to heterospecific stimuli (Experiment 2). Fast and durable learning would indicate the evolution of an efficient avoidance response. In Experiment 1, females were exposed to a heterospecific male for 1, 4 h, 4 or 8 days and then paired with that male. We found more avoidance of interspecific mating after 4 or 8 days of exposure than after 1 or 4 h of exposure. In Experiment 2, females were exposed to a heterospecific male for 8 days and then paired with that male either 10 min later or 8 days later. We found that after an 8-day delay females were highly sexually receptive to the heterospecific male. Additionally, a comparison between the current experiments and a previous study indicates that female Syrian hamsters do not require concurrent exposure to a conspecific male and a heterospecific male to learn to avoid interspecific mating; exposure to a heterospecific male is sufficient.

中文翻译：

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成年雌性仓鼠需要长期和持续地接触异种雄性以避免种间交配

种间交配通常会降低雌性的健康。在许多物种中，雌性天生就会避免异种雄性或通过在父母身上留下印记。或者，成年雌性在接触这些雄性后可以学会区分异种雄性。例如，叙利亚仓鼠 (Mesocricetus auratus) 雌性在成年期通过接触两种物种的雄性来学会区分同种雄性和土耳其仓鼠 (M.brandti) 雄性。以前没有接触过土耳其仓鼠雄性的成年雌性也会与同种和异种雄性交配。然而，在之前的一项研究中，我们发现接触异种雄性和同种雄性 8 天会导致交配回避和对异种雄性的攻击。在这里，我们进行了两个实验，以研究雌性需要多少暴露于异种雄性才能避免与异种雄性交配（实验 1），以及在没有持续暴露于异种特异性刺激的情况下这种避免持续多长时间（实验 2）。快速而持久的学习将表明有效回避反应的演变。在实验 1 中，雌性与异种雄性接触 1、4 小时、4 或 8 天，然后与该雄性配对。我们发现在暴露 4 或 8 天后比暴露 1 或 4 小时后更避免种间交配。在实验 2 中，雌性与异种雄性接触 8 天，然后在 10 分钟后或 8 天后与该雄性配对。我们发现，经过 8 天的延迟，雌性对异种雄性的性接受度很高。此外，当前实验与先前研究之间的比较表明，雌性叙利亚仓鼠不需要同时接触同种雄性和异种雄性来学习避免种间交配；接触异种雄性就足够了。