Effects of plant intraspecific diversity across three trophic levels: Underlying mechanisms and plant traits

摘要: PREMISE OF STUDY Although there is increasing recognition of the effects plant intraspecific diversity on consumers, mechanisms by which such cascade-up to higher trophic levels remain elusive. METHODS We evaluated (lima bean, Phaseolus lunatus) a suite insect herbivores (leaf-chewers, aphids, and seed-eating beetles) their third trophic-level associates (parasitoids aphid-tending ants). established plots three plants, classified as monocultures one population source or polycultures with mixtures four sources (N = 16 per level diversity). Within each plot, plants were individually placed in pots canopy contact was prevented, therefore eliminating consumers arising from changes traits due physical interactions. KEY RESULTS Plant reduced damage leaf-chewers well aphid abundance, latter effect turn ant abundance. In contrast, increased abundance beetles, but did not influence associated parasitoids. There no seed potentially predation, suggesting that differences early season herbivory between (a likely mechanism since interactions prevented) drive concomitant traits. CONCLUSIONS This study emphasizes are contingent upon associate responses within among suggests possible propagate up this food web.