Haupt Tanya M, Sinclair Brent J, Chown Steven L
Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa.
Department of Biology, The University of Western Ontario, London, Ontario N6A 5B7, Canada.
J Insect Physiol. 2017 Apr;98:108-116. doi: 10.1016/j.jinsphys.2016.12.006. Epub 2016 Dec 27.
Physiological ecologists have long assumed that thermoregulatory behaviour will evolve to optimise physiological performance. The coadaptation hypothesis predicts that an animal's preferred body temperature will correspond to the temperature at which its performance is optimal. Here we use a strong inference approach to examine the relationship between thermal preference and locomotor performance in the caterpillars of a wingless sub-Antarctic moth, Pringleophaga marioni Viette (Tineidae). The coadaptation hypothesis and its alternatives (suboptimal is optimal, thermodynamic effect, trait variation) are tested. Compared to the optimal movement temperature (22.5°C for field-fresh caterpillars and 25, 20, 22.5, 25 and 20°C following seven day acclimations to 0, 5, 10, 15 and 5-15°C respectively), caterpillar thermal preference was significantly lower (9.2°C for field-fresh individuals and 9.4, 8.8, 8.1, 5.2 and 4.6°C following acclimation to 0, 5, 10, 15 and 5-15°C, respectively). Together with the low degree of asymmetry observed in the performance curves, and the finding that acclimation to high temperatures did not result in maximal performance, all, but one of the above hypotheses (i.e. 'trait variation') was rejected. The thermal preference of P. marioni caterpillars more closely resembles temperatures at which survival is high (5-10°C), or where feeding is optimal (10°C), than where locomotion speed is maximal, suggesting that thermal preference may be optimised for overall fitness rather than for a given trait.
生理生态学家长期以来一直认为，体温调节行为会不断进化以优化生理性能。协同适应假说预测，动物偏好的体温将与其生理性能最佳时的温度相对应。在此，我们采用一种强有力的推理方法，来研究一种无翅亚南极蛾类——马氏普氏蛾（Pringleophaga marioni Viette，麦蛾科）幼虫的热偏好与运动性能之间的关系。我们对协同适应假说及其替代假说（次优即最优、热力学效应、性状变异）进行了检验。与最佳运动温度相比（刚采集的幼虫为22.5°C，在分别适应0、5、10、15和5 - 15°C七天后，最佳运动温度分别为25、20、22.5、25和20°C），幼虫的热偏好显著更低（刚采集的个体为9.2°C，适应0、5、10、15和5 - 15°C后分别为9.4、8.8、8.1、5.2和4.6°C）。结合性能曲线中观察到的低不对称程度，以及高温适应并未导致性能达到最大值这一发现，除了上述假说中的一个（即“性状变异”）外，其他假说均被否定。马氏普氏蛾幼虫的热偏好更接近生存概率高的温度（5 - 10°C），或进食最佳的温度（10°C），而非运动速度最快时的温度，这表明热偏好可能是为了整体适应性而非特定性状而优化的。
