Structure of ant-diaspore networks and their functional outcomes in a Brazilian Atlantic Forest

Abstract

Ants are able to interact with fruits and seeds that are not adapted for ant seed dispersal. In Brazil, several studies show interactions of ants with non-myrmecochorous diaspores; however, few of them have studied the structure of ant-fruit networks. The use of the network approach allows visualising multiple interactions between partners and how they are shaped by the community context. Our study aims to investigate ant-fruit networks as well as quantitative and qualitative dispersal components in a fragment of the Brazilian Atlantic Forest. We investigated the structure of interaction networks, diaspore removal rates, diaspore destination and dispersal distance over two years of observation. We constructed three interaction networks: dry season, rainy season and total, with the latter comprising the two formers. The diaspore removal rate, dispersal distance and diaspore destination experiments were performed for the plant species Miconia calvescens, Miconia prasina, Psychotria leiocarpa and Inga edulis. We recorded a large number of interactions, with diaspore cleaning being more frequent than removal. Ant-diaspore networks were nested, non-modular and little specialized. M. calvescens, M. prasina and I. edulis showed higher diaspore removal rates. Diaspore removal distances were the same among M. calvescens, M. prasina and I. edulis. In M. calvescens and I. edulis, the main diaspore destination was the ant’s nest. Our study shows that diaspore cleaning is the most common behavior in ant-diaspore interactions and there are no differences in the organization of interaction networks over the seasons. These results have implications for the future structure of plant communities, considering that a small part of the diaspores is removed, and that most of them are cleaned, favouring germination at the deposition site.

Flower Visitation by Bees, Wasps and Ants: Revealing How a Community of Flower-Visitors Establish Interaction Networks in a Botanical Garden

“…What usually happens in mutualistic plantinsect networks (e.g. flower visitors, extrafloral nectaries or seed removers) is that, due to the insects' behavior, they display low specialization, high nestedness and no modularity (Campos-Navarrete et al, 2013;Lange & Del-Claro, 2014;Anjos et al, 2018;Laviski et al, 2021). Although all hymenopteran networks follow the assumptions for insect-plant mutualistic networks, metric values are expected to be quite different for networks with each group of organisms, because they are different taxonomic groups (Campos-Navarrete et al, 2013).…”