Abstract
AbstractOver 125 million years of ant-plant interactions have culminated in one of the most intriguing evolutionary outcomes in life history. The myrmecophyte Duroia hirsuta (Rubiaceae) is known for its mutualistic association with the ant Myrmelachista schumanni and several other species, mainly Azteca, in the north-western Amazon. While both ants provide indirect defences to plants, only M. schumanni nests in plant domatia and has the unique behaviour of clearing the surroundings of its host tree from heterospecific plants, potentially increasing resource availability to its host. Using a 12-year survey, we asked how the continuous presence of either only M. schumanni or only Azteca spp. benefits the growth and defence traits of host trees. We found that the continuous presence of M. schumanni improved relative growth rates and leaf shearing resistance of Duroia better than trees with Azteca. However, leaf herbivory, dry matter content, trichome density, and secondary metabolite production were the same in all trees. Survival depended directly on ant association (> 94% of trees died when ants were absent). This study extends our understanding of the long-term effects of strict ant-plant mutualism on host plant traits in the field and reinforces the use of D. hirsuta–M. schumanni as a model system suitable for eco-co-evolutionary research on plant–animal interactions.
Funder
CTFS-Forest Global Earth Observatory Research Grants Program
LMI-BioINCA consortium
National Geographic Society Education Foundation
Universidad de las Américas project
National Geographic Society
Secretaría de Educación Superior, Ciencia, Tecnología e Innovación
Publisher
Springer Science and Business Media LLC
Reference90 articles.
1. Nelsen, M. P., Ree, R. H. & Moreau, C. S. Ant–plant interactions evolved through increasing interdependence. Proc. Natl. Acad. Sci. 115, 12253 (2018).
2. Wilson, E. O. & Hölldobler, B. The rise of the ants: a phylogenetic and ecological explanation. Proc. Natl. Acad. Sci. 102(21), 7411–7414 (2005).
3. Parker, J. & Kronauer, D. J. How ants shape biodiversity. Curr. Biol. 31(19), R1208–R1214 (2021).
4. Shingleton, A. W., Stern, D. L. & Foster, W. A. The origin of a mutualism: a morphological trait promoting the evolution of ant-aphid mutualisms. Evolution 59, 921 (2005).
5. Six, D. L. Climate change and mutualism. Nat. Rev. Microbiol. 7, 686 (2009).