Limited Physiological Compensation in Response to an Acute Microclimate Change in a Malagasy Bat
Limited Physiological Compensation in Response to an Acute Microclimate Change in a Malagasy Bat
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DOI：
10.3389/fevo.2022.779381
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发表时间：
2022-03
期刊：
影响因子：
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通讯作者：
S. Reher;Hajatiana Rabarison;J. Nowack;K. Dausmann
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文献类型：
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作者：
S. Reher;Hajatiana Rabarison;J. Nowack;K. Dausmann
快速的环境变化对吸热物种来说是一个挑战，因为它们会影响微气候和基本资源的可用性，从而对其生理产生直接和直接的影响。生理灵活性可以补偿某些生态扰动，但我们对物种在特定栖息地如何发挥作用及其适应范围的基本了解是有限的。在这里，我们研究了急性实验性小气候变化对广泛分布的马达加斯加蝙蝠（Macromycteris commersoni）两个种群热生理学的影响。该物种的种群在不同的条件下栖息，即在持续炎热潮湿的洞穴中或在不受环境条件波动影响的树叶下方。我们将每个种群的自由放养个体暴露在各自相反的条件下，从而在生态现实范围内暴露于新的小气候，同时测量代谢率和皮肤温度。森林环境中的洞穴蝙蝠维持体温的能力有限，当环境温度低于它们通常经历的洞穴温度时，两个蝙蝠就会变得体温过低。另一方面，森林蝙蝠在潮湿的洞穴环境中很难散热。然而，对热的反应出人意料地一致，所有蝙蝠在超过其热中性区的温度下都会进入麻木状态并伴有高热。因此，虽然我们观察到通过“热”麻木来灵活补偿热量的潜力，但这两个种群都表现出应对偏离其通常栖息地的急性小气候变化的潜力有限的模式。我们的研究强调，在评估物种的适应范围时，种群之间的种内变异可能会产生误导，因为变异可能来自遗传适应、发育可塑性或表型灵活性，所有这些都允许在不同时间尺度上做出补偿反应。解开这些机制并确定变异的基础对于准确预测物种在不断快速变化的栖息地和气候中生存的机会至关重要。
Rapid environmental changes are challenging for endothermic species because they have direct and immediate impacts on their physiology by affecting microclimate and fundamental resource availability. Physiological flexibility can compensate for certain ecological perturbations, but our basic understanding of how species function in a given habitat and the extent of their adaptive scope is limited. Here we studied the effect of acute, experimental microclimate change on the thermal physiology of two populations of the widespread Malagasy bat, Macronycteris commersoni. Populations of this species are found roosting under contrasting conditions, i.e., in a constant hot and humid cave or below foliage unprotected from fluctuations in ambient conditions. We exposed free-ranging individuals of each population to the respective opposite condition and thus to novel microclimate within an ecologically realistic scope while measuring metabolic rate and skin temperature. Cave bats in forest setting had a limited capacity to maintain euthermia to the point that two individuals became hypothermic when ambient temperature dropped below their commonly experienced cave temperature. Forest bats on the other hand, had difficulties to dissipate heat in the humid cave set-up. The response to heat, however, was surprisingly uniform and all bats entered torpor combined with hyperthermia at temperatures exceeding their thermoneutral zone. Thus, while we observed potential for flexible compensation of heat through “hot” torpor, both populations showed patterns suggestive of limited potential to cope with acute microclimate changes deviating from their typically occupied roosts. Our study emphasizes that intraspecific variation among populations could be misleading when assessing species’ adaptive scopes, as variation may arise from genetic adaptation, developmental plasticity or phenotypic flexibility, all of which allow for compensatory responses at differing time scales. Disentangling these mechanisms and identifying the basis of variation is vital to make accurate predictions of species’ chances for persisting in ever rapidly changing habitats and climates.