Beyond the gardens: The extended mutualism from ant‐garden ants to nectary‐bearing plants growing in Amazon tree‐fall gaps

Abstract

AbstractThe regime of frequent small disturbances, such as the formation of tree‐fall gaps, is an important mechanism maintaining the diversity in tropical forests. Occurring primarily in forest gaps, or in riparian vegetation, ant gardens (hereafter AGs) are mutualistic associations involving several epiphytic plant species and ants. In the Amazon rainforest, a widespread AGs association is assembled by two aggressive species of parabiotic ants (Camponotus femoratus and Crematogaster levior). Working together, these ants aggressively monopolize food resources and attack any intruder on the AGs. Here, we demonstrated the extended protective effect of parabiotic ants on the leaf herbivory of neighboring plants, contrasting plants with and without extrafloral nectaries (hereafter EFNs). We performed the fieldwork in South Amazonia where we found 33 forest gaps, 16 with and 17 without AGs. Independently of the presence of AGs, plants possessing EFNs have less area removed by herbivores and fewer leaves with herbivore marks than those without EFNs. This decrease in herbivory was remarkable on EFN‐plants growing in gaps that also harbor AGs. Additional manipulative experiments confirmed this pattern: The AG‐ants were more efficient than no‐AG ants in removing live termite baits placed on EFN‐plants, but few attacks were observed on plants without EFNs. Thus, AG‐ants can extend their role in defending ant gardens from other plants growing in the same area, particularly those with EFNs. This extension of the mutualism benefits can affect the dynamics of the ecological succession and coevolutionary process in the Amazon forest.Abstract in Portuguese is available with online material