Coping with environmental change: the importance of adaptive thermoregulatory flexibility for Malagasy bats

动物物种的能量收支与它们所处的环境密切相关。发生在不同生态和气候条件下的物种必须能够灵活地应对这些变化的条件。对于季节性、人为造成的碎片化或全球气候变化等具有挑战性的变化也是如此，因为它们往往涉及能源需求的增加。马达加斯加特别受人为变化的影响，因为大约90%的原始环境已经被改变。尽管马达加斯加蝙蝠具有重要的生态系统服务和对生态系统保护的巨大贡献，以及对其自然栖息地的严重威胁，但令人惊讶的是，人们对马达加斯加蝙蝠知之甚少。该项目的主要目标是研究马达加斯加蝙蝠物种的能量管理，特别是与不断变化的环境条件、栖息地选择和寄生虫负荷相关的商业蝙蝠。被调查的物种生活在岛上最干旱和不可预测的地区，该地区在环境温度、降水和资源可用性方面经历了剧烈的季节性变化。因此，我们将直接在野外检查蝙蝠的能量收支和热生物学，并将这些生理参数与当地环境特征联系起来，并在两种不同栖息可能性的栖息地（洞穴与树洞）中进行比较，从而得出这些生理反应的灵活性的结论。我们还记录了异温性的发生和强度，这是小型吸热哺乳动物应对能量和水瓶颈的最有力的反应之一。本研究将为了解蝙蝠在极端环境下的生态生理需求和反应提供新的信息，这对确定对哺乳动物生存至关重要的栖息地特征具有重要意义。此外，我们的研究结果将能够可靠地预测蝙蝠承受环境和气候变化的能力。最后但并非最不重要的是，我们的结果将使我们能够与1)来自其他地区和大陆的温带和热带蝙蝠进行比较，2)马达加斯加狐猴的睡眠模式有充分的记录。这些比较将使我们能够解决哺乳动物体温调节进化的重要问题，以及异温动物的变异性和可能的半胚性特征。

The energy budgets of animal species are closely linked to their environment. Species that occur in habitats with differing ecological and climatic conditions must be able to flexibly cope with these varying conditions. This holds also true for changes owing to seasonality, human-caused fragmentation or global climate change that can be challenging, because they often involve increased energy requirements. Madagascar is particularly affected by anthropogenic changes, as > 90% of the original environments are already altered. Despite their important ecosystem services and their great contribution to the preservation of ecosystems, and the acute threat to their natural habitat, surprisingly little is known about Malagasy bats.The major objective of this project is to examine the energy management of Malagasy bat species, especially Hipposideros commersoni, related to varying and changing environmental conditions, roost choice, and parasite load. The species investigated live in the most arid and unpredictable zone of the island, which undergoes drastic seasonal changes in ambient temperature, precipitation and resource availability. Therefore, we will examine the energy budgets and thermal biology of the bats directly in the field and relate these physiological parameters to local environmental characteristics, and compare them in two habitats with different roosting possibilities (cave vs. tree hollows), leading to very different microclimatic conditions, to draw conclusion on the flexibility of these physiological responses. We also document occurrence and intensity of heterothermy, one of the most powerful responses for small, endothermic mammals to cope with energy and water bottlenecks. Our study will contribute new information about the ecological and physiological demands and responses of bat species inhabiting extreme environments, which is crucial for the identification of habitat characteristics critical for the survival of mammals in general. Moreover, our results will enable reliable predictions about the capacity of bats to endure environmental and climatic change. Last but not least, our results will enable us to make comparisons with 1) temperate and tropical bats from other regions and continents and 2) the well-documented torpor patterns of Malagasy lemurs. These comparisons will allow us to address important, unanswered questions on the evolution of mammalian thermoregulation and the variability and possibly plesiomorphic character of heterothermy.