Dispersal and spatial heterogeneity allow coexistence between enemies and protective mutualists

Ecology and Evolution

Timothée Poisot¹  James D. Bever²  Peter H. Thrall³ 

[1] Université Montpellier II, Institut des Sciences de l'Evolution, UMR 5554, Montpellier, France;Department of Biology, Indiana University, Bloomington, Indiana;CSIRO Plant Industry, Canberra, Australian Capital Territory, Australia

关键词: Community ecology;    source‐sink dynamics;    metacommunities;    host‐symbiont interactions;    coexistence theory;    spatial dynamics;   

DOI  :  10.1002/ece3.1151

来源: Wiley

【 摘 要 】

Abstract

Protective mutualisms, where a symbiont reduces the negative effects of another species on a shared host, represent a common type of species interaction in natural communities, yet it is still unclear what ecological conditions might favor their emergence. Studies suggest that the initial evolution of protective mutualists might involve closely related pathogenic variants with similar life histories, but different competitive abilities and impacts on host fitness. We derive a model to evaluate this hypothesis and show that, in general, a protective variant cannot spread from rarity or exclude a more pathogenic strain. While the conditions allowing mutualist invasion are more likely with increased environmental productivity, they still depend on initial densities in the invaded patch exceeding a threshold, highlighting the likely importance of spatial structure and demographic stochasticity. Using a numerical simulation approach, we show that regional coexistence is in fact possible in an explicitly spatial system and that, under some circumstances, the mutualist population can exclude the enemy. More broadly, the establishment of protective mutualists may be favored when there are other life-history differences from more pathogenic symbionts, such as vertical transmission or additional direct benefits to hosts.

【 授权许可】

CC BY   
© 2014 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.

Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.