Parental Investment and Selection

9709212帕克这个项目将分析雄性和雌性狮子在后代生存方面的投资程度。在大多数情况下，雄狮会与狮群的其他成员争夺食物，但常驻狮群的雄狮则会提供重要的防御，以对抗群外的雄狮。灵长类动物分开觅食，雄性花了相当大的努力试图重新安置雌性和幼崽。当幼崽最需要保护，以免被陌生人杀害时，母熊最有可能向常驻的公熊透露自己的行踪，但当喂养竞争最激烈时，母熊最不愿意透露自己的行踪。雌性也会根据幼崽的脆弱程度来权衡后代的相对繁殖价值，更有可能在幼崽几乎注定失败的情况下恢复对年长幼崽的专属投资。由于雄性亲代投资对幼崽的生存非常重要，本研究旨在研究与雄性雌性合作和交配行为相关的因素，并包括一系列的配偶选择和入侵者模拟实验。据预测，雌性更喜欢与鬃毛较大或较深的雄性交配，而雄性则会优先攻击鬃毛较短或较浅的陌生人。这项研究将调查鬃毛是否是一种条件依赖的特征，并将检查各种营养和激素因素，这些因素可能会导致鬃毛大小和颜色的变化。研究将在位于坦桑尼亚贡贝国家公园的美国国家科学基金会长期生态研究基地进行。这项研究的结果将使我们更好地理解狮子复杂的社会行为背后的进化因素。

9709212 Packer This project will analyze the extent to which male and female lions invest in the survival of offspring. Under most conditions, male lions compete for food with the rest of their pride, but resident males provide important defense against extra- group males. Pridemates forage apart and males spend considerable effort trying to relocate the females and young. Females should be most likely to reveal their whereabouts to resident males when their cubs are in greatest need of protection from infanticidal strangers but least helpful when feeding competition would be most intense. Females are also expected to weigh the relative reproductive value of successive broods according to the vulnerability of their younger cubs, being more likely to resume exclusive investment in their older brood when the younger brood is virtually doomed. Because male parental investment is so important to cub survival, this research is directed at examining factors related to male-female cooperation and mating behaviors, and includes a series of mate-choice and intruder- simulation experiments. Females are predicted to prefer to mate with males with larger or darker manes, whereas males should preferentially attack strangers with shorter or lighter manes. The study will investigate whether the mane is a condition-dependent trait, and will examine a variety of nutritional and hormonal factors that are likely to contribute to variability in mane size and color. Studies will be conducted in the field at the NSF Long-Term Ecological Research site in the Gombe National Park, Tanzania. Results of this research will allow a better understanding of the evolutionary factors underlying the complex social behavior of lions.