Delbarco-Trillo Javier, Johnston Robert E
Department of Psychology, Cornell University, Uris Hall, Ithaca, NY 14853, USA.
Evol Ecol. 2011 Mar;25(2):391-401. doi: 10.1007/s10682-010-9429-7.
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.
种间交配通常会降低雌性的适应性。在许多物种中，雌性天生会避免与异种雄性交配，或者通过对父母的印记来避免。另外，成年雌性在接触到异种雄性后也可以学会区分它们。例如，叙利亚仓鼠（Mesocricetus auratus）雌性在成年期通过接触两种雄性，学会区分同种雄性和土耳其仓鼠（M. brandti）雄性。之前未接触过土耳其仓鼠雄性的成年雌性会同样地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天会导致交配回避以及对异种雄性的攻击行为。在此，我们进行了两项实验，以研究雌性需要接触异种雄性多长时间才能避免与异种雄性交配（实验1），以及在没有持续接触异种刺激的情况下，这种回避行为会持续多长时间（实验2）。快速且持久的学习表明进化出了一种有效的回避反应。在实验1中，雌性接触异种雄性1小时、4小时、4天或8天，然后与该雄性配对。我们发现，接触4天或8天后比接触1小时或4小时后，种间交配的回避现象更多。在实验2中，雌性接触异种雄性8天，然后在10分钟后或8天后与该雄性配对。我们发现，延迟8天后，雌性对异种雄性具有很高的性接受度。此外，当前实验与之前一项研究的比较表明，叙利亚仓鼠雌性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。
