Description of the herbivore and natural enemy community associated with the seeds of an invasive plant in Brazil

Abstract

1. Studies have shown that fruits of plants from the Fabaceae family harbour a diversecommunity of herbivorous insects and their natural enemies. Despite this observa-tion, we still lack information on the specific interactions within these multi-trophiccommunities. Herein, we describe the food web of insects associated with fruitsand seeds ofLeucaena leucocephala(Fabaceae), an invasive plant in Brazil, and theirrelationship with plant traits including seed biomass.2. We found 17 species of insects distributed across three trophic levels. The mainherbivore species sampled wasAcanthoscelides macrophthalmus(Coleoptera, Chry-somelidae, Bruchinae), which was responsible for most of the seed predationand associated with the highest parasitoid biodiversity (N=10 species). Four otherherbivorous species were lower in abundance, including a previously unreportedLepidopteran species with two parasitoids and one hyperparasitoid associated with it.3. Seeds with more mass promoted an increase in insect abundance, insect speciesrichness, and the number of links and connectivity. We observed two native para-sitoid species,Paracrias pluteusandStenocorse suldamericanos, shift from herbivoreson native plants to herbivores on the invasiveL. leucocephala, consistent with apotential host shift. However, more investigation is required to ascertain the effectsof recent shifts of native insect communities (on native plants) to non-native onesand their consequences on plant fitness. Our study contributes to the understand-ing of the dynamics of communities and food webs in unknown systems, specifi-cally in fruits of an invasive plant, and provides information about the influence ofdifferent plant traits on these communities.