Department of Entomology and Plant Pathology, Auburn University, Auburn, AL, USA.
School of Fisheries, Aquaculture, and Aquatic Sciences, Auburn University, Auburn, AL, USA.
Ecol Lett. 2019 May;22(5):875-883. doi: 10.1111/ele.13245. Epub 2019 Mar 7.
When herbivorous insects interact, they can increase or decrease each other's fitness. As it stands, we know little of what causes this variation. Classic competition theory predicts that competition will increase with niche overlap and population density. And classic hypotheses of herbivorous insect diversification predict that diet specialists will be superior competitors to generalists. Here, we test these predictions using phylogenetic meta-analysis. We estimate the effects of diet breadth, population density and proxies of niche overlap: phylogenetic relatedness, physical proximity and feeding-guild membership. As predicted, we find that competition between herbivorous insects increases with population density as well as phylogenetic and physical proximity. Contrary to predictions, competition tends to be stronger between than within feeding guilds and affects specialists as much as generalists. This is the first statistical evidence that niche overlap increases competition between herbivorous insects. However, niche overlap is not everything; complex feeding guild effects indicate important indirect interactions.
当草食性昆虫相互作用时，它们可以增加或减少彼此的适合度。目前，我们对导致这种变化的原因知之甚少。经典的竞争理论预测，竞争会随着生态位重叠和种群密度的增加而增加。经典的草食性昆虫多样化假说预测，食性专化者将比广食者更具竞争力。在这里，我们使用系统发育元分析来检验这些预测。我们估计了饮食广度、种群密度和生态位重叠的替代指标（系统发育关系、物理接近度和取食群组成员）的影响。正如预测的那样，我们发现草食性昆虫之间的竞争随着种群密度以及系统发育和物理接近度的增加而增加。与预测相反的是，竞争往往在取食群内比取食群间更强，并且对专食者和广食者的影响相同。这是统计证据首次表明生态位重叠会增加草食性昆虫之间的竞争。然而，生态位重叠并不是一切；复杂的取食群效应表明存在重要的间接相互作用。
