Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, Arizona, 85721, USA.
Ecology. 2018 Jan;99(1):196-203. doi: 10.1002/ecy.2066. Epub 2017 Dec 18.
Numerous mechanisms may allow species to coexist. We tested for frequency-dependent predation, a mechanism predicted by theory and established as a foraging behavior for many types of animals. Our field test included multiple prey species exposed in situ to multiple predator species and individuals to determine whether the prey species experienced predation patterns that were frequency dependent. The prey were seeds of three species of Sonoran Desert winter annual plants while the predator species were a guild of nocturnal seed foraging heteromyid and murid rodents that co-occur naturally in the same community as the desert annuals at Tumamoc Hill near Tucson. Seeds of one species were much preferred over the other two. Nonetheless, we found the net effect of rodent foraging to be positively frequency dependent (the preference for each species is higher when it is common than when it is uncommon) as has been previously hypothesized. This frequency-dependent predation should function as a species coexistence promoting mechanism in concert with the storage effect that has been previously demonstrated for this system.
许多机制可以使物种共存。我们测试了频率依赖捕食，这是一种理论预测的机制，并被确立为许多类型动物的觅食行为。我们的野外测试包括将多种猎物物种暴露在多个捕食者物种和个体中，以确定猎物物种是否经历了频率依赖的捕食模式。猎物是三种索诺兰沙漠冬季一年生植物的种子，而捕食者物种是一组夜间觅食的异鼠兔和鼠科啮齿动物，它们与沙漠一年生植物在图马莫克山附近的图森自然共存。一种物种的种子比其他两种更受青睐。尽管如此，我们发现啮齿动物觅食的净效应确实是频率依赖的（当一种物种常见时，对它的偏好高于不常见时），这与之前的假设一致。这种频率依赖的捕食应该与之前为该系统证明的储存效应一起，作为一种促进物种共存的机制。
