Insights into a novel three-partner interaction between ants, coreids (Hemiptera: Coreidae) and extrafloral nectaries: implications for the study of protective mutualisms

ARANDA-RICKERT; FRACCHIA; YELA; MARAZZI

ARTHROPOD-PLANT INTERACTIONS

SPRINGER

Lugar: Berlin; Año: 2017

1872-8855

AbstractExtrafloral nectar of plants and honeydew ofhemipterans are the common mediators of facultativeinteractions that involve ants as a mobile strategy ofdefence. The outcome of these interactions can vary frommutualistic to commensalistic or even antagonistic,depending on the ecological context and the interactingspecies. Here, we explore a novel, three-partner interactioninvolving ants, the coreidDersagrena subfoveolata(Hemiptera) and the extrafloral nectaries (EFNs) bearingplantSenna aphylla(Fabaceae) in semi-arid NorthwestArgentina. We surveyed natural areas and conducted antexclusion experiments, to understand how each pairwiseinteraction influences the overall outcome among the threeinteracting parts. The outcome of the interactions wasassessed for experimental plants as the reproductive outputand herbivore abundances and for coreids as predatorabundances. We found that the coreids occurred exclu-sively onS. aphyllaplants and that at least nine ant speciesinteracted with the EFNs as well as with the coreids.Coreid occurrence and abundance depended on ant densi-ties, which in turn, was determined by the presence ofactively secreting EFNs. Coreid and ant presence did notinfluence plant reproductive success, and ants provided tocoreids some biotic defence, mainly against vespid wasppredators, but had no effect on non-coreid herbivores. Weconclude that the interaction outcome is commensalisticbetween ants and plants (assuming that EF nectar is notcostly for the plant), antagonistic between coreids andplants, and mutualistic between coreids and ants. The sumof all outcomes is net positive effect for ants and coreids,and net slightly negative to neutral for plants.