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

Adriana Sanchez,Sean Brady

doi:10.1371/journal.pone.0143535

Abstract

The association between the myrmecophyte Triplaris and ants of the genus Pseudomyrmex is an often-reported example of mutualism but no molecular studies have examined this association to date. In this study, the interspecific relationships of Triplaris were reconstructed using five molecular markers (two chloroplast and three nuclear), and the relationships of the associated Pseudomyrmex using two molecular regions (one mitochondrial and one nuclear). A data set including all known collections of plant hosts and resident ants was also compiled. The pattern of distribution of both organisms reveals that there are varying degrees of host specificity; most ants show broader host usage (promiscuous) but one species (P. dendroicus) is faithful to a single species of Triplaris. In most ant-plant interactions, host usage is not specific at the species level and preferences may result from geographical or ecological sorting. The specificity of P. dendroicus could be based on chemical recognition of the host they were raised on.

Highlights

Myrmecophytism, or plants that associate with ants, are a common symbiosis in nature, pervasive and diverse in the tropics, especially in the Neotropics
There was incongruence between chloroplast and nuclear regions according to ILD (p = 0.01), when bootstrap supports between regions were compared, few relationships that were incongruent are moderately or highly supported (> 70%)
Few interspecific relationships of Triplaris were supported with the individual gene regions and there were only three supported incongruences

Summary

Introduction

Myrmecophytism, or plants that associate with ants, are a common symbiosis in nature, pervasive and diverse in the tropics, especially in the Neotropics (more than 200 species; [1]). This is a mutualistic association as, in return for being housed and sometimes fed, plant-ants protect their host myrmecophyte from encroaching vegetation, herbivores and pathogens, and/or provide them with nutrients (i.e., myrmecotrophy) [2, 3]. There are several well-known cases of these associations, such as the interaction between Vachellia-Pseudomyrmex, Cecropia-Azteca, and Macaranga-Crematogaster Most studies on these interactions focus on ecological aspects such as defense against herbivores and the effect

Methods

Results

Conclusion