Energetics of Mammalian Reproduction and Life History

9309994凯纳吉将在1984年以来一直在研究的金毛松鼠种群中调查生殖能量消耗、身体状况和繁殖成功之间的关系。这项研究的生理维度集中在自然条件下的密集生理表现--最大产量和最大工作负荷，以及伴随而来的能量需求。这方面的两个典型案例是哺乳期女性的父母生产支出峰值，以及与交配、攻击性和防御相关的男性行为支出峰值。在研究的每一个方面，表现都是根据近端能量平衡及其表型变化来量化的，然后根据人口学的角度来评估最终的成功，即生存和未来的繁殖。将审查每日能量消耗的直接关系，以及身体质量和状况与生存的中介关系，认识到种群的所有成员的生殖表现可能以类似的峰值水平运行，由此产生的生殖产出是单独优化的。在自由生活的动物中，我们使用稳定的同位素来测量能量消耗，并通过全身电导率来测量身体状况(脂肪与瘦身成分)。将通过实验操纵母亲的食物供应来调查女性生殖、摄取和支出的上限。越冬的能量平衡将通过无线电遥测冬眠松鼠的麻木模式来评估。将通过能量平衡和能量供应的试验性操作来评估一岁雄性的灵活性和可变生殖成熟度。这项研究应该有助于对种群中个体生理和行为的变化如何转化为在生活史过程中生存和繁殖成功的表达的综合理解。***

9309994 Kenagy The relationship between reproductive energy expenditures, body condition and reproductive success will be investigated in a population of golden-mantled ground squirrels that has been under study since 1984. The physiological dimension of the proposed research focuses on intensive physiological performances under natural conditions -- maximal production and maximal work load, and the accompanying demand for energy. Two model cases of this are the peak parental production expenditures that occur in lactating females and the peak behavior expenditures that occur in males associated with mating, aggression and defense. In each aspect of the study, performances are quantified in terms of proximal energy balance and its phenotypic variation, and then the ultimate success will be evaluated in terms of demography, i.e., survival and future reproduction. The direct relationship of daily energy expenditure, and the intermediary relationship of body mass and condition to survival will be examined, recognizing that reproductive performances may operate at similar peak levels for all members of a population and that the resulting reproductive output is individually optimized. In freeliving animals we measure energy expenditure using stable isotopes, and body condition (fat vs. lean components) by total body electrical conductivity. The upper limits of female reproduction, intake and expenditure will be investigated by experimentally manipulating maternal food supply. Overwinter energy balance will be evaluated by radiotelemetry of torpor patterns in hibernating squirrels. Flexibility and variable reproductive maturity in yearling males will be evaluated in terms of energy balance and an experimental manipulation of energy supply. This research should contribute to an integrated understanding of how variation in the physiology and behavior of individuals in a population translates into the expression of survival and reproductive success over the cou rse of life history. ***