Generalist foraging of pollinators: diet expansion at high density
Generalist foraging of pollinators: diet expansion at high density
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DOI：
10.1111/j.1365-2745.2008.01405.x
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发表时间：
2008-09-01
影响因子：
5.5
通讯作者：
Dajoz, Isabelle
中科院分区：
文献类型：
--
作者：
Fontaine, Colin;Collin, Carine L.;Dajoz, Isabelle
1.植物与传粉者的相互作用对大多数被子植物的繁殖至关重要。当面临扰动时，植物传粉网络可能是强大的，主要是由于高度通才物种的存在。扰动反过来又会影响传粉者如何利用它们的食物来源，从而影响它们的泛化程度。特别是，传粉者的泛化可能会随着觅食密度而变化。在高密度下，植物群落中可利用的花资源将比低密度下更快地耗尽。根据最佳觅食理论（OFT），这种资源的减少应该导致饮食宽度的增加。研究了传粉者密度对熊蜂取食宽度的影响。我们记录了8个殖民地的熊蜂的个人觅食行为。它们在由五种植物组成的实验植物群落中，在一种或几种同种植物的存在下觅食。饮食宽度计算为访问的植物物种的数量，以及莱文指数。从个体和殖民地水平分析了觅食密度对食物宽度的影响.我们发现，觅食密度影响程度的泛化在个人和群体水平。一个更具竞争力的环境增加了个人的泛化，OFT预测，并降低了跨殖民地泛化的变异性。此外，我们还发现熊蜂的体型大小与食物宽度变化幅度呈正相关.合成.我们的研究揭示了植物传粉系统的复杂性的另一个层次，表明传粉昆虫的饮食广度是一个灵活的性状，这是由于行为适应资源的可用性。更一般地说，觅食昆虫的饮食通过竞争资源的变化可能会随之而来的人为生态系统干扰和影响植物传粉网络的功能。
1. Plant-pollinator interactions are crucial for the reproduction of most angiosperms. When faced with perturbations, plant-pollinator networks might be robust mainly due to the presence of highly generalist species. Perturbations can, in turn, affect how pollinators exploit their food sources and therefore their degree of generalization.2. In particular, generalization of pollinators might vary with forager density. At high densities floral resources available in plant communities would be more rapidly depleted than at low densities. According to optimal foraging theory (OFT), this decrease in resources should lead to an increase in diet breadth.3. We investigated the impact of pollinator density on diet breadth of Bombus terrestris. We recorded the individual foraging behaviour of bumblebees from eight colonies. They foraged in presence of either one or several conspecifics on experimental plant communities composed of five plant species. Diet breadth was calculated as the number of plant species visited, as well as by the Levins index. We analyzed the effect of forager density on diet breadth at both the individual and the colony levels.4. We found that forager density affected degree of generalization at individual and colony levels. A more competitive environment increased individual generalization, as predicted by OFT, and decreased the variability in generalization across colonies. Moreover, we found that bumblebee size was positively related to the amplitude of diet breadth change.5. Synthesis. Our study sheds light on an additional level of complexity of plant-pollinator systems, showing that pollinator diet breadth is a flexible trait which results from behavioural adaptation to resource availability. More generally, changes in foraging insects' diet via competition for resources are likely to ensue from anthropogenic ecosystem disturbance and to impact upon the functioning of plant-pollinator networks.