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

Abstract

Studies have shown that fruits of plants from the Fabaceae family harbour a diverse community of herbivorous insects and their natural enemies. Despite this observation, we still lack information on the specific interactions within these multi‐trophic communities. Herein, we describe the food web of insects associated with fruits and seeds of Leucaena leucocephala (Fabaceae), an invasive plant in Brazil, and their relationship with plant traits including seed biomass. We found 17 species of insects distributed across three trophic levels. The main herbivore species sampled was Acanthoscelides macrophthalmus (Coleoptera, Chrysomelidae, Bruchinae), which was responsible for most of the seed predation and associated with the highest parasitoid biodiversity (N = 10 species). Four other herbivorous species were lower in abundance, including a previously unreported Lepidopteran species with two parasitoids and one hyperparasitoid associated with it. Seeds with more mass promoted an increase in insect abundance, insect species richness, and the number of links and connectivity. We observed two native parasitoid species, Paracrias pluteus and Stenocorse suldamericanos, shift from herbivores on native plants to herbivores on the invasive L. leucocephala, consistent with a potential host shift. However, more investigation is required to ascertain the effects of recent shifts of native insect communities (on native plants) to non‐native ones and their consequences on plant fitness. Our study contributes to the understanding of the dynamics of communities and food webs in unknown systems, specifically in fruits of an invasive plant, and provides information about the influence of different plant traits on these communities.