Post-association barrier to host switching maintained despite strong selection in a novel mutualism.

ABSTRACT: Following a host shift, repeated co-passaging of a mutualistic pair is expected to increase fitness over time in one or both species. Without adaptation, a novel association may be evolutionarily short-lived as it is likely to be outcompeted by native pairings. Here, we test whether experimental evolution can rescue a low-fitness novel pairing between two sympatric species of Steinernema nematodes and their symbiotic Xenorhabdus bacteria. Despite low mean fitness in the novel association, considerable variation in nematode reproduction was observed across replicate populations. We selected the most productive infections, co-passaging this novel mutualism nine times to determine whether selection could improve the fitness of either or both partners. We found that neither partn

SUBMITTER: Dinges ZM 

PROVIDER: S-EPMC9204852 | biostudies-literature | 2022 Jul

REPOSITORIES: biostudies-literature