Multichannel feeding by spider functional groups is driven by feeding strategies and resource availability

Multichannel feeding, whereby consumers feed across resource channels such as upon herbivore and detritivore resources, acts to link discrete compartments of a food web with implications for ecosystem functioning and stability. Currently however, we have little understanding which feeding strategies of consumers underlie multichannel feeding. We therefore link spider functional group and resource density-dependent or density-independent feeding strategies to multichannel feeding by quantifying not only consumer diet, but also the relative availability of resources. Here we analysed herbivore (green) and detritivore (brown) prey use by spider communities in grasslands, and tested if available prey biomass proportions were linked to observed spider dietary proportions. Different spider functional groups each linked green and brown resource channels, but while green prey were always consumed in proportion to their relative biomass, brown prey were consumed independently of proportion by...多通道取食（multichannel feeding）指消费者通过植食性资源与腐食性资源等多种资源渠道获取食物，其可连接食物网中彼此独立的营养功能模块，对生态系统功能与稳定性具有重要意义。然而目前我们对支撑多通道取食的消费者取食策略仍知之甚少。为此，我们不仅量化消费者的食性组成，同时测定资源的相对可获得性，以此将蜘蛛功能群、依赖于资源密度或不依赖于资源密度的取食策略与多通道取食关联起来。本研究针对草原生态系统中的蜘蛛群落，分析其对植食性（绿色）和腐食性（棕色）猎物的利用情况，并检验猎物生物量的可获得比例是否与观测到的蜘蛛食性比例存在关联。不同蜘蛛功能群均能连接绿色与棕色资源渠道，不过尽管蜘蛛对植食性猎物的取食比例始终与其相对生物量相符，但其对腐食性猎物的取食则不受比例影响，由……