Jumbam Keafon R, Jackson Susan, Terblanche John S, McGeoch Melodie A, Chown Steven L
Centre for Invasion Biology, Department of Botany and Zoology, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa.
J Insect Physiol. 2008 Jun;54(6):1008-14. doi: 10.1016/j.jinsphys.2008.03.011. Epub 2008 Apr 3.
For the Argentine ant Linepithema humile, bioclimatic models often predict narrower optimal temperature ranges than those suggested by behavioural and physiological studies. Although water balance characteristics of workers of this species have been thoroughly studied, gaps exist in current understanding of its thermal limits. We investigated critical thermal minima and maxima and upper and lower lethal limits following acclimation to four temperatures (15, 20, 25, 30 degrees C; 12L:12D photoperiod) in adult workers of the Argentine ant, L. humile, collected from Stellenbosch, South Africa. At an ecologically relevant rate of temperature change of 0.05 degrees Cmin(-1), CTMax varied between 38 and 40 degrees C, and CTMin varied between 0 and 0.8 degrees C. In both cases the response to acclimation was weak. A significant time by exposure temperature interaction was found for upper and lower lethal limits, with a more pronounced effect of acclimation at longer exposure durations. Upper lethal limits varied between 37 and 44 degrees C, whilst lower lethal limits varied between -4 and -10.5 degrees C, with an acclimation effect more pronounced for upper than lower lethal limits. A thermal envelope for workers of the Argentine ant is provided, demonstrating that upper thermal limits do likely contribute to distributional limits, but that lower lethal limits and limits to activity likely do not, or at least for workers who are not exposed simultaneously to the demands of load carriage and successful foraging behaviour.
对于阿根廷蚁Linepithema humile，生物气候模型通常预测的最佳温度范围比行为和生理研究表明的范围更窄。尽管对该物种工蚁的水分平衡特征已进行了深入研究，但目前对其热极限的理解仍存在差距。我们对从南非斯泰伦博斯采集的阿根廷蚁Linepithema humile成年工蚁在适应四种温度（15、20、25、30摄氏度；12小时光照：12小时黑暗光周期）后，研究了临界热最小值和最大值以及上下致死极限。在生态相关的0.05摄氏度每分钟的温度变化速率下，临界热最大值（CTMax）在38至40摄氏度之间变化，临界热最小值（CTMin）在0至0.8摄氏度之间变化。在这两种情况下，对适应的反应都很微弱。对于上下致死极限，发现了暴露温度与时间的显著交互作用，在较长暴露持续时间下，适应的影响更为明显。上致死极限在37至44摄氏度之间变化，而下致死极限在-4至-10.5摄氏度之间变化，适应对上致死极限的影响比对下致死极限更明显。提供了阿根廷蚁工蚁的热耐受范围，表明上热极限可能确实对分布极限有影响，但下致死极限和活动极限可能没有影响，或者至少对于那些不同时面临负重运输和成功觅食行为需求的工蚁来说没有影响。
