Protection against herbivory in the mutualism between Pseudomyrmex dendroicus (Formicidae) and Triplaris americana (Polygonaceae)

Abstract

Herbivory significantly impacts the growth and reproduction of plants. Many plants have developed ways to defend against herbivores and one common strategy is to associate with ants. In many ant-plant interactions, ants are known to protect their host. However, in the Neotropical ant-plant genus Triplaris, the benefits provided by associated ants have never been tested. Many Pseudomyrmex spp. ants are obligate inhabitants of Triplaris spp. trees. In this study, Triplaris americana was studied in association with Pseudomyrmex dendroicus, an ant highly specific to its host (it has not been collected from any other species of Triplaris). Ant exclusion experiments were carried out to assess the protective effect of ants. In addition, ant behavior was monitored in control plants to study the mechanisms by which ants might confer protection against herbivory. Ant removal led to a more than 15-fold increase in herbivory. Pseudomyrmex dendroicus are active at all times of day and night and aggressively and efficiently remove insect herbivores from their host.

Fidelity and Promiscuity in an Ant-Plant Mutualism: A Case Study of Triplaris and Pseudomyrmex

“…In the case of host recognition, ants are known to respond to chemical cues from their hosts. They rapidly recruit in response to herbivory attacks [ 27 , 67 ] and queens select their host plant primarily based on chemical recognition [ 64 , 65 , 68 , 69 , 70 , 71 ]. Chemical analysis of myrmecophytic Macaranga showed that even closely related species, sharing the same ant partners, can have very different scent patterns and that foundress queens have the capacity to distinguish between different hosts [ 64 ].…”

“…The Triplaris - Pseudomyrmex interaction is a well-known case of myrmecophytism in the Neotropics and some ecological studies have addressed the interaction [ 21 , 22 , 23 , 24 , 25 , 26 , 27 ]. However, although there has been some work done on the relationships between the Pseudomyrmex species associated with Triplaris [ 28 ], there has been no attempt to compare the phylogenetic framework of these two groups of organisms.…”

“…These species are distributed from southern Panama to southern Brazil. Some ecological experiments have studied the symbiosis between Triplaris and Pseudomyrmex , and it is thought that in exchange for the nesting sites, the ant partners protect their host plants against herbivore damage [ 23 , 27 , 32 ] and maintain the plants free of pathogens. Pseudomyrmex is also known to prune the vegetation around their host [ 23 ].…”

Heterodimeric insecticidal peptide provides new insights into the molecular and functional diversity of ant venoms

“…Ants belonging to the genus Pseudomyrmex possess venoms that rapidly subdue prey and effectively deter herbivores, suggesting that they contain both neurotoxic and cytotoxic compounds [9].…”

Neotropical ant-plant Triplaris americana attracts Pseudomyrmex mordax ant queens during seedling stages

“…In myrmecophytic associations, ant-plants provide nesting space inside domatia, and in some cases, food rewards, while ants protect plants against herbivory, pathogens, and encroaching vegetation (Rico-Gray and Oliveira 2007 ; Mayer et al 2014 ; Sanchez and Bellota 2015 ). Myrmecophytism is widespread and very diverse in the Tropics where at least 100 different plant genera are inhabited by ant colonies (Davidson and McKey 1993 ; Chomicki and Renner 2015 ).…”