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Abstract Interactions between species are widely understood to have promoted the diversification of life on Earth, but how interactions spur the formation of new species remains unclear. Interacting species often become locally adapted to each other, but they may also be subject to shared dispersal limitations and environmental conditions. Moreover, theory predicts that different kinds of interactions have different effects on diversification. To better understand how species interactions promote diversification, we compiled population genetic studies of host plants and intimately associated herbivores, parasites, and mutualists. We used Bayesian multiple regressions and the BEDASSLE modeling framework to test whether host and associate population structures were correlated over and above the potentially confounding effects of geography and shared environmental variation. We found that associates' population structure often paralleled their hosts' population structure, and that this effect is robust to accounting for geographic distance and climate. Associate genetic structure was significantly explained by plant genetic structure somewhat more often in antagonistic interactions than in mutualistic ones. This aligns with a key prediction of coevolutionary theory that antagonistic interactions promote diversity through local adaptation of antagonists to hosts, while mutualistic interactions more often promote diversity via the effect of hosts' geographic distribution on mutualists' dispersal.
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A need to consider the evolutionary genetics of host–symbiont mutualisms
Abstract Despite the ubiquity and importance of mutualistic interactions, we know little about the evolutionary genetics underlying their long‐term persistence. As in antagonistic interactions, mutualistic symbioses are characterized by substantial levels of phenotypic and genetic diversity. In contrast to antagonistic interactions, however, we, by and large, do not understand how this variation arises, how it is maintained, nor its implications for future evolutionary change. Currently, we rely on phenotypic models to address the persistence of mutualistic symbioses, but the success of an interaction almost certainly depends heavily on genetic interactions. In this review, we argue that evolutionary genetic models could provide a framework for understanding the causes and consequences of diversity and why selection may favour processes that maintain variation in mutualistic interactions.
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- PAR ID:
- 10364559
- Publisher / Repository:
- Oxford University Press
- Date Published:
- Journal Name:
- Journal of Evolutionary Biology
- Volume:
- 33
- Issue:
- 12
- ISSN:
- 1010-061X
- Format(s):
- Medium: X Size: p. 1656-1668
- Size(s):
- p. 1656-1668
- Sponsoring Org:
- National Science Foundation
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