Speciation by Symbiosis: the Microbiome and Behavior

Abstract

Species are fundamental units of comparison in biology. The newly discovered importance and ubiquity of host-associated microorganisms are now stimulating work on the roles that microbes can play in animal speciation. We previously synthesized the literature and advanced concepts of speciation by symbiosis with notable attention to hybrid sterility and lethality. Here, we review recent studies and relevant data on microbes as players in host behavior and behavioral isolation, emphasizing the patterns seen in these analyses and highlighting areas worthy of additional exploration. We conclude that the role of microbial symbionts in behavior and speciation is gaining exciting traction and that the holobiont and hologenome concepts afford an evolving intellectual framework to promote research and intellectual exchange between disciplines such as behavior, microbiology, genetics, symbiosis, and speciation. Given the increasing centrality of microbiology in macroscopic life, microbial symbiosis is arguably the most neglected aspect of animal and plant speciation, and studying it should yield a better understanding of the origin of species.

Delta Hemolysin and Phenol-Soluble Modulins, but Not Alpha Hemolysin or Panton-Valentine Leukocidin, Induce Mast Cell Activation

“…Microorganisms are increasingly being recognized to have profound effects on the host they invade (Shropshire and Bordenstein, 2016). In many cases, host behaviors are altered upon infection by diverse pathogens, including bacteria (Cameron and Sperandio, 2015).…”

Prophage WO genes recapitulate and enhance Wolbachia-induced cytoplasmic incompatibility

“…Females infected with the same Wolbachia strain rescue this lethality. Despite more than 40 years of research 1 and relevance to symbiont-induced speciation 2,3 , as well as control of arbovirus vectors 4,5,6 and agricultural pests 7 , the bacterial genes underlying CI remain unknown. Here, we use comparative and transgenic approaches to demonstrate that two differentially transcribed, codiverging genes in the eukaryotic association module of prophage WO 8 from Wolbachia strain w Mel recapitulate and enhance CI.…”

Diet, Gut Microbes and Host Mate Choice

“…The growing interest in the effects of symbionts, and in particular of acquired gut bacteria, on the mating behavior of their hosts is stimulating much discussion into the significance of the resulting outcomes for driving divergence in host reproductive traits . It is also contributing to a broader consideration of the extent to which the host and its microbiome can act as a selectable “individual” or holobiont . Key to understanding the strength of selection at this level is to understand the fitness effects of any manipulations by microbes of their hosts and specifically which parties benefit.…”

“…[4,24,86] It is also contributing to a broader consideration of the extent to which the host and its microbiome can act as a selectable "individual" or holobiont. [88] Key to understanding the strength of selection at this level is to understand the fitness effects of any manipulations by microbes of their hosts and specifically which parties benefit. Along with this, the way in which microbes are inherited or re-exposed to their hosts in each generation is also key in ascertaining the relative potential for selection at the level of the holobiont.…”