title: Disentangling a Holobiont - Recent Advances and Perspectives inNasoniaWasps.
abstract: The parasitoid wasp genusNasonia(Hymenoptera: Chalcidoidea) is a well-established model organism for insect development, evolutionary genetics, speciation, and symbiosis. The host-microbiota assemblage which constitutes theNasoniaholobiont (a host together with all of its associated microbes) consists of viruses, two heritable bacterial symbionts and a bacterial community dominated in abundance by a few taxa in the gut. In the wild, all fourNasoniaspecies are systematically infected with the obligate intracellular bacteriumWolbachiaand can additionally be co-infected withArsenophonus nasoniae.These two reproductive parasites have different transmission modes and host manipulations (cytoplasmic incompatibility vs. male-killing, respectively). Pioneering studies onWolbachiainNasoniademonstrated that closely relatedNasoniaspecies harbor multiple and mutually incompatibleWolbachiastrains, resulting in strong symbiont-mediated reproductive barriers that evolved early in the speciation process. Moreover, research on host-symbiont interactions and speciation has recently broadened from its historical focus on heritable symbionts to the entire microbial community. In this context, eachNasoniaspecies hosts a distinguishable community of gut bacteria that experiences a temporal succession during host development and members of this bacterial community cause strong hybrid lethality during larval development. In this review, we present theNasoniaspecies complex as a model system to experimentally investigate questions regarding: (i) the impact of different microbes, including (but not limited to) heritable endosymbionts, on the extended phenotype of the holobiont, (ii) the establishment and regulation of a species-specific microbiota, (iii) the role of the microbiota in speciation, and (iv) the resilience and adaptability of the microbiota in wild populations subjected to different environmental pressures. We discuss the potential for easy microbiota manipulations inNasoniaas a promising experimental approach to address these fundamental aspects.
authors.affiliation: Rowland Institute at Harvard, Harvard University, Cambridge MA, USA.
authors.forename: Jessica
authors.initials: J
authors.lastname: Dittmer
authors.affiliation: Department of Biological Sciences, Vanderbilt University, Nashville TN, USA.
authors.forename: Edward J
authors.initials: EJ
authors.lastname: van Opstal
authors.affiliation: Department of Biological Sciences, Vanderbilt University, Nashville TN, USA.
authors.forename: J Dylan
authors.initials: JD
authors.lastname: Shropshire
authors.affiliation: Department of Biological Sciences, Vanderbilt University, NashvilleTN, USA; Department of Pathology, Microbiology, and Immunology, Vanderbilt University, NashvilleTN, USA.
authors.forename: Seth R
authors.initials: SR
authors.lastname: Bordenstein
authors.affiliation: Institute of Integrative Biology, University of Liverpool Liverpool, UK.
authors.forename: Gregory D D
authors.initials: GD
authors.lastname: Hurst
authors.affiliation: Rowland Institute at Harvard, Harvard University, Cambridge MA, USA.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Brucker
keywords: Arsenophonus; Nasonia; Wolbachia; host-symbiont interactions; microbiome; symbiosis