McCluney Kevin E, Sabo John L
P.O. Box 874601, School of Life Sciences, Arizona State University, Tempe, Arizona 85287-4601, USA.
Ecology. 2009 Jun;90(6):1463-9. doi: 10.1890/08-1626.1.
Community ecology has long focused on energy and nutrients as currencies of species interactions. Evidence from physiological ecology and recent studies suggest that in terrestrial systems, water may influence animal behavior and global patterns of species richness. Despite these observations, water has received little attention as a currency directly influencing animal species interactions. Here, we show that the per capita interaction strength between predatory wolf spiders and their primary prey, field crickets, is strong (-0.266) when predators and prey are maintained in ambient dry conditions, but is near zero (0.001) when water is provided ad libitum. Moreover, crickets consume 31-fold more moist leaf material in ambient dry conditions, switching from old litter to moist green leaves when free water is scarce. Under dry conditions, animals may make foraging decisions based first on water needs, not energy or nutrients, suggesting strong and predictable effects of alterations in aridity on species interactions.
长期以来，群落生态学一直将能量和营养物质视为物种相互作用的货币。生理生态学的证据和近期研究表明，在陆地系统中，水可能会影响动物行为和物种丰富度的全球格局。尽管有这些观察结果，但水作为直接影响动物物种相互作用的一种货币却很少受到关注。在此，我们表明，当捕食性狼蛛及其主要猎物田蟋蟀处于环境干燥条件下时，它们之间的人均相互作用强度很强（-0.266），但当随意提供水时，该强度接近零（0.001）。此外，在环境干燥条件下，蟋蟀消耗的潮湿叶片材料是原来的31倍，在自由水稀缺时，它们会从陈旧的落叶转向潮湿的绿叶。在干燥条件下，动物可能首先根据水分需求而非能量或营养物质来做出觅食决策，这表明干旱程度的改变对物种相互作用具有强烈且可预测的影响。
