Scharf Inon, Nulman Einat, Ovadia Ofer, Bouskila Amos
Department of Life Sciences, Ben-Gurion University of the Negev, 84105 Beer Sheva, Israel.
Am Nat. 2006 Sep;168(3):350-7. doi: 10.1086/506921. Epub 2006 Jul 26.
Various foraging modes are employed by predators in nature, ranging from ambush to active predation. Although the foraging mode may be limited by physiological constraints, other factors, such as prey behavior and distribution, may come into play. Using a simulation model, we tested to what extent the relative success of an ambush and an active predator changes as a function of the relative velocity and movement directionality of prey and active predator. In accordance with previous studies, we found that when both active predator and prey use nondirectional movement, the active mode is advantageous. However, as movement becomes more directional, this advantage diminishes gradually to 0. Previous theoretical studies assumed that animal movement is nondirectional; however, recent field observations show that in fact animal movement usually has some component of directionality. We therefore suggest that our simulation is a better predictor of encounter rates than previous studies. Furthermore, we show that as long as the active predator cannot move faster than its prey, it has little or no advantage over the ambush predator. However, as the active predator's velocity increases, its advantage increases sharply.
自然界中的捕食者采用各种觅食模式，从伏击到主动捕食。尽管觅食模式可能受到生理限制，但其他因素，如猎物行为和分布，也可能起作用。我们使用一个模拟模型，测试了伏击型捕食者和主动捕食者的相对成功率如何随着猎物和主动捕食者的相对速度及运动方向性而变化。与之前的研究一致，我们发现当主动捕食者和猎物都采用无方向性运动时，主动捕食模式具有优势。然而，随着运动变得更具方向性，这种优势会逐渐减小至零。之前的理论研究假设动物运动是无方向性的；然而，最近的实地观察表明，实际上动物运动通常具有一定的方向性成分。因此，我们认为我们的模拟比之前的研究更能准确预测相遇率。此外，我们表明，只要主动捕食者的移动速度不能超过其猎物，它相对于伏击型捕食者几乎没有优势或根本没有优势。然而，随着主动捕食者速度的增加，其优势会急剧增加。
