Bronson F H
Biol Reprod. 1985 Feb;32(1):1-26. doi: 10.1095/biolreprod32.1.1.
The objectives of this paper are to organize our concepts about the environmental regulation of reproduction in mammals and to delineate important gaps in our knowledge of this subject. The environmental factors of major importance for mammalian reproduction are food availability, ambient temperature, rainfall, the day/night cycle and a variety of social cues. The synthesis offered here uses as its core the bioenergetic control of reproduction. Thus, for example, annual patterns of breeding are viewed as reflecting primarily the caloric costs of the female's reproductive effort as they relate to the energetic costs and gains associated with her foraging effort. Body size of the female is an important consideration since it is correlated with both potential fat reserves and life span. Variation in nutrient availability may or may not be an important consideration. The evolutionary forces that have shaped the breeding success of males usually are fundamentally different from those acting on females and, by implication, the environmental controls governing reproduction probably also often differ either qualitatively or quantitatively in the two sexes. Mammals often live in habitats where energetic and nutrient challenges vary seasonally, even in the tropics. When seasonal breeding is required, a mammal may use a predictor such as photoperiod or a secondary plant compound to prepare metabolically for reproduction. A reasonable argument can be made, however, that opportunistic breeding, unenforced by a predictor, may be the most prevalent strategy extant among today's mammals. Social cues can have potent modulating actions. They can act either via discrete neural and endocrine pathways to alter specific processes such as ovulation, or they can induce nonspecific emotional states that secondarily affect reproduction. Many major gaps remain in our knowledge about the environmental regulation of mammalian reproduction. For one, we have a paucity of information about the annual patterns of breeding and about the mechanisms controlling these patterns in the most common mammals on the planet-the small to average-sized mammals living in the tropics. We probably have only a shallow conceptualization of the way available energy and nutrients control reproduction and, likewise, we may have only a narrow view of the potential kinds and uses of seasonal predictors. Finally, we have little appreciation of the way environmental cues interact with each other to control reproduction.
本文的目的是梳理我们关于哺乳动物繁殖的环境调节的概念，并勾勒出我们在该主题知识方面的重要空白。对哺乳动物繁殖至关重要的环境因素包括食物供应、环境温度、降雨量、昼夜循环以及各种社会信号。这里提供的综合内容以繁殖的生物能量控制为核心。因此，例如，年度繁殖模式主要被视为反映了雌性繁殖努力的热量成本，因为它们与觅食努力相关的能量成本和收益有关。雌性的体型是一个重要的考虑因素，因为它与潜在的脂肪储备和寿命都相关。营养物质可用性的变化可能是也可能不是一个重要的考虑因素。塑造雄性繁殖成功的进化力量通常与作用于雌性的力量根本不同，这意味着控制繁殖的环境因素在两性中可能在质量或数量上也常常不同。哺乳动物通常生活在能量和营养挑战随季节变化的栖息地，即使在热带地区也是如此。当需要季节性繁殖时，哺乳动物可能会使用诸如光周期或次生植物化合物等预测因子来为繁殖进行代谢准备。然而，可以提出一个合理的观点，即不受预测因子强制的机会性繁殖可能是当今哺乳动物中最普遍存在的策略。社会信号可以产生强大的调节作用。它们可以通过离散的神经和内分泌途径来改变特定过程，如排卵，或者它们可以引发非特异性情绪状态，进而影响繁殖。我们在关于哺乳动物繁殖的环境调节方面的知识仍然存在许多重大空白。一方面，我们缺乏关于繁殖年度模式以及控制地球上最常见的哺乳动物（生活在热带地区的小型到中型哺乳动物）这些模式的机制的信息。我们可能对可用能量和营养物质控制繁殖的方式只有肤浅的概念理解，同样，我们对季节性预测因子的潜在种类和用途可能也只有狭隘的看法。最后，我们对环境信号相互作用以控制繁殖的方式了解甚少。
