Heritable symbionts in a world of varying temperature

Abstract

Heritable microbes represent an important component of the biology, ecology and evolution of many plants, animals and fungi, acting as both parasites and partners. In this review, we examine how heritable symbiont-host interactions may alter host thermal tolerance, and how the dynamics of these interactions may more generally be altered by thermal environment. Obligate symbionts, those required by their host, are considered to represent a thermally sensitive weak point for their host, associated with accumulation of deleterious mutations. As such, these symbionts may represent an important determinant of host thermal envelope and spatial distribution. We then examine the varied relationship between thermal environment and the frequency of facultative symbionts that provide ecologically contingent benefits or act as parasites. We note that some facultative symbionts directly alter host thermotolerance. We outline how thermal environment will alter the benefits/costs of infection more widely, and additionally modulate vertical transmission efficiency. Multiple patterns are observed, with symbionts being cold sensitive in some species and heat sensitive in others, with varying and non-coincident thresholds at which phenotype and transmission are ablated. Nevertheless, it is clear that studies aiming to predict ecological and evolutionary dynamics of symbiont-host interactions need to examine the interaction across a range of thermal environments. Finally, we discuss the importance of thermal sensitivity in predicting the success/failure of symbionts to spread into novel species following natural/engineered introduction.

Independent cytoplasmic incompatibility induced byCardiniumandWolbachiamaintains endosymbiont coinfections in haplodiploid thrips populations

“…In combination with the different CI types in our study, this matches previous predictions about the relationships of CI types and transmission efficiency; that is FM will select for increased transmission efficiency, while MD may favor incomplete transmission . Furthermore, temperature effects on a wider diversity of heritable symbionts have recently been reviewed by Corbin et al (2017). However, the endosymbiont transmission efficiencies measured in the laboratory experiments contradicted field findings that demonstrated repeated loss of Wolbachia but not Cardinium in invasive populations.…”

Mechanisms structuring host–parasitoid networks in a global warming context: a review

“…from a mother to its offspring) is reduced at high temperatures for Wolbachia (Hurst et al, 2000). Thus, variation in natural infection rates and symbiont prevalence in a focal species depend on interactions between the endosymbiont and the prevailing thermal conditions (Watts et al, 2009;Corbin et al, 2017). Thus, variation in natural infection rates and symbiont prevalence in a focal species depend on interactions between the endosymbiont and the prevailing thermal conditions (Watts et al, 2009;Corbin et al, 2017).…”

Metacommunity theory for transmission of heritable symbionts within insect communities

“…In this review, our use of the term “symbiont” refers broadly to commensal, mutualistic, or parasitic bacteria that exist in close physical association with their host. We focus on insect–bacteria associations because insects are often a model system for both community ecology and symbiosis studies, and bacteria are common members of microbiomes that have a well‐documented history of affecting insect host ecology (Bourtzis et al, ; Corbin, Heyworth, Ferrari, & Hurst, ; Crotti et al, ; Ross et al, ) and are relatively easy to identify with modern molecular methods. More specifically, we focus on the heritable bacteria that contextually transition between being beneficial and detrimental for their host.…”