Recognition in a social symbiosis: chemical phenotypes and nestmate recognition behaviors of neotropical parabiotic ants

PLoS One. 2013;8(2):e56492. doi: 10.1371/journal.pone.0056492. Epub 2013 Feb 22.

Abstract

Social organisms rank among the most abundant and ecologically dominant species on Earth, in part due to exclusive recognition systems that allow cooperators to be distinguished from exploiters. Exploiters, such as social parasites, manipulate their hosts' recognition systems, whereas cooperators are expected to minimize interference with their partner's recognition abilities. Despite our wealth of knowledge about recognition in single-species social nests, less is known of the recognition systems in multi-species nests, particularly involving cooperators. One uncommon type of nesting symbiosis, called parabiosis, involves two species of ants sharing a nest and foraging trails in ostensible cooperation. Here, we investigated recognition cues (cuticular hydrocarbons) and recognition behaviors in the parabiotic mixed-species ant nests of Camponotus femoratus and Crematogaster levior in North-Eastern Amazonia. We found two sympatric, cryptic Cr. levior chemotypes in the population, with one type in each parabiotic colony. Although they share a nest, very few hydrocarbons were shared between Ca. femoratus and either Cr. levior chemotype. The Ca. femoratus hydrocarbons were also unusually long-chained branched alkenes and dienes, compounds not commonly found amongst ants. Despite minimal overlap in hydrocarbon profile, there was evidence of potential interspecific nestmate recognition -Cr. levior ants were more aggressive toward Ca. femoratus non-nestmates than Ca. femoratus nestmates. In contrast to the prediction that sharing a nest could weaken conspecific recognition, each parabiotic species also maintains its own aggressive recognition behaviors to exclude conspecific non-nestmates. This suggests that, despite cohabitation, parabiotic ants maintain their own species-specific colony odors and recognition mechanisms. It is possible that such social symbioses are enabled by the two species each using their own separate recognition cues, and that interspecific nestmate recognition may enable this multi-species cooperative nesting.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Ants / physiology*
  • Behavior, Animal / physiology
  • Nesting Behavior / physiology
  • Odorants
  • Symbiosis / physiology*

Grants and funding

Funding for this research was provided by the American Association for the Advancement of Science Pacific Division Alan E. Leviton Student Research Award, the Society for Integrative and Comparative Biology Fellowship for Graduate Student Travel, the Margaret C. Walker Fund for Teaching and Research in Systematic Entomology, the Johannes Joos Fund, and a Post-Graduate Fellowship from the Natural Sciences and Engineering Research Council of Canada (NSERC) to VJE. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Funding URLs: http://www.aaas.org/, http://www.sicb.org/, http://www.nserc-crsng.gc.ca/.