Horizontal transfer of facultative endosymbionts is limited by host relatedness

Piotr Łukasik, Huifang Guo, Margriet van Asch, Lee M Henry, H Charles J Godfray, Julia Ferrari

Research output: Contribution to journalArticlepeer-review


Heritable microbial symbionts can have important effects on many aspects of their hosts' biology. Acquisition of a novel symbiont strain can provide fitness benefits to the host, with significant ecological and evolutionary consequences. We measured barriers to horizontal transmission by artificially transferring facultative symbionts from the grain aphid, Sitobion avenae, and five other aphid species into two clonal genotypes of S. avenae. We found the symbiont Hamiltonella defensa establishes infections more easily following a transfer from the same host species and that such infections are more stable. Infection success was also higher when the introduced symbiont strain was more closely related to the strain that was originally present in the host (but which had previously been removed). There were no differences among successfully established symbiont strains in their effect on aphid fecundity. Hamiltonella defensa did not confer protection against parasitoids in our S. avenae clones, although it often does in other aphid hosts. However, strains of the symbiont Regiella insecticola originating from two host species protected grain aphids against the pathogenic fungus Pandora neoaphidis. This study helps describe the extent to which facultative symbionts can act as a pool of adaptations that can be sampled by their eukaryote hosts.

Original languageEnglish
Pages (from-to)2757-2766
Number of pages10
JournalEvolution: international journal of organic evolution
Issue number10
Publication statusPublished - Oct 2015

Bibliographical note

© 2015 The Author(s).

Cite this