Diet, Gut Microbes and Host Mate Choice

• Published in: BioEssays 2018-12, Vol.40 (12), p.n/a
• Main Authors: Leftwich, Philip T., Hutchings, Matthew I., Chapman, Tracey
• Format: Article
• Language: English
• Subjects: Assortative mating; Diet; Endosymbionts; Evolution; Fruit flies; gut microbiome; holobiont; Intestinal microflora; Mate selection; Microorganisms; Reproductive isolation; selection; speciation; Symbiosis; unit of selection
• ISSN: 0265-9247; 1521-1878
• DOI: 10.1002/bies.201800053

All organisms live in close association with microbes. However, not all such associations are meaningful in an evolutionary context. Current debate concerns whether hosts and microbes are best described as communities of individuals or as holobionts (selective units of hosts plus their microbes). Recent reports that assortative mating of hosts by diet can be mediated by commensal gut microbes have attracted interest as a potential route to host reproductive isolation (RI). Here, the authors discuss logical problems with this line of argument. The authors briefly review how microbes can affect host mating preferences and evaluate recent findings from fruitflies. Endosymbionts can potentially influence host RI given stable and recurrent co‐association of hosts and microbes over evolutionary time. However, observations of co‐occurrence of microbes and hosts are ripe for misinterpretation and such associations will rarely represent a meaningful holobiont. A framework in which hosts and their microbes are independent evolutionary units provides the only satisfactory explanation for the observed range of effects and associations. All organisms live in close association with microbes. However, not all such associations are meaningful in an evolutionary context. The authors evaluate whether hosts and microbes are best described as communities of individuals or as unitary holobionts. The authors conclude that true holobionts of microbiomes and hosts will be extremely rare.