A classic question in evolutionary biology is whether behavioral flexibility hastens or hinders evolutionary change. The latter idea, that behavior reduces the number of environmental states experienced by an organism and buffers that organism against selection, has been dubbed the "Bogert Effect" after Charles Bogert, the biologist who first popularized the phenomenon using data from lizards. The Bogert Effect is pervasive when traits like body temperature, which tend to be invariant across space in species that behaviorally thermoregulate, are considered. Nevertheless, behavioral thermoregulation decreases or stops when spatial variation in operative temperature is low. We compared environmental temperatures, thermoregulatory behavior, and a suite of physiological and morphological traits between two populations of the southern rock agama (Agama atra) in South Africa that experience different climatic regimes. Individuals from both populations thermoregulated efficiently, maintaining body temperatures within their preferred temperature range throughout most of their activity cycle. Nevertheless, they differed in the thermal sensitivity of resting metabolic rate at cooler body temperatures and in morphology. Our results support the common assertion that thermoregulatory behavior may prevent divergence in traits like field-active body temperature, which are measured during periods of high environmental heterogeneity. Nevertheless, we show that other traits may be free to diverge if they are under selection during times when environments are homogenous. We argue that the importance of the Bogert Effect is critically dependent on the nature of environmental heterogeneity and will therefore be relevant to some traits and irrelevant to others in many populations.

中文翻译：

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Bogert效应和环境异质性。

进化生物学中的一个经典问题是行为灵活性是加速还是阻碍了进化的改变。后一种想法（即行为减少了生物体经历的环境状态的数量并缓冲了该生物体不受选择的影响）在生物学家查尔斯·博格特（Charles Bogert）首先使用蜥蜴的数据进行了推广之后，被称为“博格特效应”。当考虑到像体温这样的特性（这些特性在行为上具有温度调节作用的物种中在空间上往往是不变的）时，博格特效应普遍存在。但是，当操作温度的空间变化较小时，行为温度调节会降低或停止。我们比较了环境温度，温度调节行为，以及南非的两个南部蜥蜴种群（Agama atra）之间的一套生理和形态特征，这些种群经历了不同的气候条件。来自两个种群的个体均能有效地进行体温调节，从而在整个活动周期的大部分时间内将体温保持在其优选的温度范围内。然而，它们在较低的体温和形态上的静息代谢率的热敏感性不同。我们的研究结果支持这样一个普遍的主张，即温度调节行为可以防止在像田间活动的体温这样的特质上发散，这些特征是在环境高度异质性时期测量的。然而，我们表明，如果在环境同质的时期选择其他性状，它们可能会自由分化。