Herbivores use a wide range of factors to choose their host, including their own physiological states, physical characteristics of plants and the degree of competition. Field observations of herbivores in their native habitats provide a means for simultaneously estimating the relative importance of these factors, but statistical analysis of all these factors may be challenging. Here we used a 7-week dataset of leaf-cutting ant (Atta cephalotes) foraging in a diverse Neotropical arboretum containing 193 tree species (822 trees) to examine the relative role of tree phylogeny, territoriality and tree functional characteristics using a phylogenetic generalized least squares (PGLS) model. We observed that 54 tree species (117 trees) were foraged by the ants. This pattern was not random, but reflected known features of leaf-cutting ant foraging behaviour, such as a preference for larger trees and the decreased likelihood of foraging at the periphery of a colony’s territory. However, random effects such as tree phylogeny, the identity of individual trees and colony-specific effects explained most of the variation in foraging data. A significant phylogenetic effect on foraging likelihood (λ = 0.28), together with repeated measures of foraging on the same tree species, allowed estimation of relative palatability for each plant species. PGLS models can be flexibly scaled to include other covariates for even more complex investigation of foraging behaviour, and the link function can be modified to include the amount of plants foraged. As a result, PGLS can be used as a flexible framework for the study of LCA foraging.

中文翻译：

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综合宿主植物系统发育、植物性状、种内竞争和重复测量，使用多食草食动物、切叶蚂蚁的田间行为系统发育混合模型

草食动物利用多种因素来选择宿主，包括自身的生理状态、植物的物理特性和竞争程度。对原生栖息地的食草动物的实地观察提供了一种同时估计这些因素相对重要性的方法，但对所有这些因素的统计分析可能具有挑战性。这里我们使用了一个为期 7 周的切叶蚁数据集（头足目) 在包含 193 个树种（822 棵树）的多样化新热带植物园中觅食，以使用系统发育广义最小二乘 (PGLS) 模型检查树系统发育、地域性和树功能特征的相对作用。我们观察到蚂蚁觅食了 54 种树种（117 棵树）。这种模式不是随机的，而是反映了切叶蚁觅食行为的已知特征，例如偏爱较大的树木以及在蚁群领土周边觅食的可能性降低。然而，树木系统发育、个体树木的身份和群体特异性效应等随机效应解释了觅食数据的大部分变化。对觅食可能性的显着系统发育影响（λ = 0.28），以及对同一树种的重复觅食测量，允许估计每种植物的相对适口性。PGLS 模型可以灵活缩放以包含其他协变量，以对觅食行为进行更复杂的调查，并且可以修改链接函数以包括觅食的植物数量。因此，PGLS 可用作研究 LCA 觅食的灵活框架。