The curious case of the camelthorn: competition, coexistence and nest-site limitation in a multispecies mutualism

Campbell, H., Fellowes, M. D.E. ORCID: https://orcid.org/0000-0001-5431-8637 and Cook, J. (2015) The curious case of the camelthorn: competition, coexistence and nest-site limitation in a multispecies mutualism. American Naturalist, 186 (6). E172-E181. ISSN 0003-0147 doi: 10.1086/683462

Abstract/Summary

Myrmecophyte plants house ants in domatia in exchange for protection from herbivores. Ant-myrmecophyte mutualisms exhibit two general patterns due to competition between ants for plant occupancy: i) domatia nest-sites are a limiting resource and ii) each individual plant hosts one ant species at a time. However, individual camelthorn trees (Vachellia erioloba) typically host two to four ant species simultaneously, often coexisting in adjacent domatia on the same branch. Such fine-grain spatial coexistence brings into question the conventional wisdom on ant-myrmecophyte mutualisms. Camelthorn ants appear not to be nest-site limited, despite low abundance of suitable domatia, and have random distributions of nest-sites within and across trees. These patterns suggest a lack of competition between ants for domatia and contrast strongly with other ant-myrmecophyte systems. Comparison of this unusual case with others suggests that spatial scale is crucial to coexistence or competitive exclusion involving multiple ant species. Furthermore, coexistence may be facilitated when co-occurring ant species diverge strongly on at least one niche axis. Our conclusions provide recommendations for future ant-myrmecophyte research, particularly in utilising multispecies systems to further our understanding of mutualism biology.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/45901
Identification Number/DOI	10.1086/683462
Refereed	Yes
Divisions	Life Sciences > School of Biological Sciences > Ecology and Evolutionary Biology
Publisher	University of Chicago Press
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