Abstract:
Flowering plants require conspecific pollen to reproduce but they often also receive heterospecific pollen, suggesting that pollinators carry mixed pollen loads. However, little is known about drivers of abundance, diversity or composition of pollen carried by pollinators. Are insect-carried pollen loads shaped by pollinator traits, or do they reflect available floral resources? We quantified pollen on 251 individual bees and 95 flies in a florally diverse community. We scored taxonomic order, sex, body size, hairiness and ecological specialization of pollinators, and recorded composition of available flowers. We used phylogenetically controlled model selection to compare relative influences of pollinator traits and floral resources on abundance, diversity and composition of insect-carried pollen. We tested congruence between composition of pollen loads and available flowers. Pollinator size, specialization and type (female bee, male bee, or fly) described pollen abundance, diversity and composition better than floral diversity. Pollen loads varied widely among insects (10-80,000,000 grains, 1-16 species). Pollen loads of male bees were smaller, but vastly more diverse than those of female bees, and equivalent in size but modestly more diverse than those of flies. Pollen load size and diversity were positively correlated with body size but negatively correlated with insect ecological specialization. These traits also drove variation in taxonomic and phylogenetic composition of insect-carried pollen loads, but composition was only weakly congruent with available floral resources. Qualities of pollinators best predict abundance and diversity of carried pollen indicating that functional composition of pollinator communities may be important to structuring heterospecific pollen transfer among plants.
摘要:
开花的植物需要同种花粉来繁殖,但它们通常也会接受异源花粉,表明传粉者携带混合花粉。然而,对丰富的驱动因素知之甚少,传粉者携带的花粉的多样性或组成。昆虫携带的花粉负荷是由传粉者性状塑造的,还是它们反映了可用的花卉资源?我们对花序多样的群落中的251只蜜蜂和95只苍蝇的花粉进行了量化。我们对分类顺序进行了评分,性别,身体尺寸,传粉者的毛羽和生态专业化,并记录可用花卉的组成。我们使用系统发育控制的模型选择来比较传粉者性状和花卉资源对丰度的相对影响,昆虫携带花粉的多样性和组成。我们测试了花粉负荷的组成与可用花朵之间的一致性。传粉者大小,专业化和类型(雌性蜜蜂,雄蜂,或苍蝇)描述花粉丰度,多样性和成分优于花卉多样性。花粉负荷在昆虫中差异很大(10-80,000,000粒,1-16种)。雄性蜜蜂的花粉负荷较小,但是比雌性蜜蜂的种类要多得多,大小相当,但比苍蝇更多样化。花粉负荷大小和多样性与体型呈正相关,而与昆虫生态专业化呈负相关。这些特征还推动了昆虫携带花粉负荷的分类学和系统发育组成的变化,但是构图与可用花卉资源的一致性较弱。传粉者的素质可以最好地预测所携带花粉的丰度和多样性,这表明传粉者群落的功能组成对于构建植物之间的异源花粉转移可能很重要。