Department of Psychology, Southwestern University, USA.
Physiol Behav. 2012 Feb 1;105(3):868-76. doi: 10.1016/j.physbeh.2011.10.022. Epub 2011 Oct 26.
The present study was designed to determine if male physiology and male reproductive behavior predict reproductive success in Long-Evans rats. Mating behavior was observed in sexually naïve, naturally cycling female rats during behavioral estrous that were given the opportunity to mate with two males simultaneously. DNA analysis of offspring born following these mating encounters was used to identify the paternity of each pup. In order to assess the effect of mate choice during these mating encounters on reproductive success, one male rat in each pair was categorized as the preferred mate if the female spent more time (>50%) with him during the mating test of the present study. Furthermore, each male in the pairs was categorized as "attractive" or "non-attractive" by computing the number of females that preferred each male across many mating tests. Similar to results reported in Lovell et al. (2007), during 76% of these mating tests the same male rat in each pair was preferred by different female rats. Overall attractiveness of individual male rats predicted reproductive success in the present study. Interestingly, "attractive" males sired significantly FEWER pups than "non-attractive" males. Neither behavioral (e.g., latency to first sexual stimulation, number of sexual stimulations) nor physiological measures (e.g., body weight, urinary testosterone levels) of male rats predicted their reproductive success. In conclusion, the present results indicate that certain features of some males are more attractive to females, but attractive males are at a reproductive disadvantage (as measured by the number of pups sired). Although basal urinary testosterone levels did not differ between males that sired the majority of pups in a litter and males that sired few or none of the pups in a litter, aggression and/or other physiological measures of fertility (e.g., penile reflexes) may differ between males that are attractive to females and those that have a reproductive advantage.
本研究旨在确定雄性生理学和雄性生殖行为是否能预测长耳大仓鼠的生殖成功。在自然发情的性未成熟雌性大鼠的发情行为期观察交配行为，这些雌性大鼠有机会同时与两只雄性大鼠交配。通过对这些交配后出生的后代的 DNA 分析，确定每个幼崽的亲代。为了评估在这些交配中选择配偶对生殖成功的影响，如果雌性在本研究的交配测试中与一只雄性大鼠相处的时间超过 50%，则将这对中的一只雄性大鼠归类为首选配偶。此外，通过计算每只雄性大鼠在多次交配测试中被雌性大鼠选择的次数，将每对雄性大鼠中的每只雄性大鼠归类为“有吸引力”或“无吸引力”。与 Lovell 等人（2007 年）的报告结果相似，在这些交配测试的 76%中，每对中的同一只雄性大鼠被不同的雌性大鼠所喜欢。个体雄性大鼠的整体吸引力预测了本研究中的生殖成功。有趣的是，“有吸引力”的雄性大鼠所产的幼崽明显少于“无吸引力”的雄性大鼠。雄性大鼠的行为（例如，首次性刺激的潜伏期，性刺激的次数）或生理（例如，体重，尿液中的睾丸激素水平）措施均不能预测其生殖成功。总之，本研究结果表明，某些雄性大鼠的某些特征对雌性更有吸引力，但有吸引力的雄性大鼠在生殖方面处于劣势（以产仔数衡量）。尽管大多数幼崽的尿液睾丸激素水平与产仔数少或无的雄性大鼠之间没有差异，但攻击性和/或其他生育生理指标（例如，阴茎反射）可能在雌性大鼠中有所不同雄性大鼠和那些具有生殖优势的雄性大鼠。
