Microbiomes, plausible players or not in alteration of host behavior.

Ã˜Yvind Ã˜Verli,Marianne Coulon,Ludovic Bonhomme,David G Biron

doi:10.3389/fmicb.2014.00775

Abstract

Many parasites can affect the physiology and behavior of their hosts in ways that seem to improve the parasites' chances of completing their life cycle (Biron and Loxdale, 2013; Lafferty and Shaw, 2013; Webster et al., 2013). These parasite species are so-called “manipulative parasites.” Common habitats of manipulative parasites are the host's body cavity, muscles and brain (Lafferty and Shaw, 2013). Typically the host's neural, endocrine, neuromodulatory, and immunomodulatory systems are targeted (Adamo, 2013; Lafferty and Shaw, 2013). In evolutionary biology, manipulation of host behavior by parasites is considered to be an example of the “extended phenotype” concept (Dawkins, 1982; Libersat et al., 2009). There are numerous fascinating cases of alteration of host behavior induced by a parasite; for instance, the suicidal behavior of crickets induced by hairworms (Thomas et al., 2002; Biron and Loxdale, 2013). Many studies on strategies used by manipulative parasites assume that only two organisms are involved in crosstalk based on Dawkins' assumption: the host and a manipulative parasite. However, hosts are frequently invaded by more than one species of parasite (Ferrari and Vavre, 2011; Cezilly et al., 2014). The interests of different parasitic species may conflict; for example, two parasites may share an intermediate host but require a different definitive host. Parasite-parasite interactions in the intermediate host can result in perturbation of the parasite infection process for each parasite species (Lafferty and Shaw, 2013; Cezilly et al., 2014). As far as we know, microbiomes are not considered to be taking part in crosstalk between an aquatic host and a manipulative parasite. Therefore, we first briefly present the background for microbiomes as plausible and underestimated players in the crosstalk in host-manipulative parasite associations in aquatic ecosystems, and secondly we discuss concepts and -omics methods to determine whether or not host microbiomes can influence host behavior in aquatic models. Finally, we discuss the importance of considering context-dependent changes in the analysis of -omics data to decode and understand the role of a host microbiome in the alteration of host behavior in aquatic ecosystems.

Highlights

Laboratoire “MicroorganismesEdited by: Jonathan P. Zehr, University of California, Santa Cruz, USA Reviewed by: Peter R. Girguis, Harvard University, USA Marja Annika Tiirola, University of Jyväskylä, Finland Keywords: alteration of host behavior, manipulative parasite, microbiome, micro-organisms, host-parasite cross-talk
Many parasites can affect the physiology and behavior of their hosts in ways that seem to improve the parasites’ chances of completing their life cycle (Biron and Loxdale, 2013; Lafferty and Shaw, 2013; Webster et al, 2013)
Pioneer studies on microbiomes were done on animal models and humans (i) to identify microbiomes in healthy individuals; (ii) to decipher microbiome responses to host pathology, parasite invasion, host nutrition and host stress; and (iii) to determine plausible impacts of microbiomes on animal behavior (Smith et al, 2007; Ezenwa et al, 2012; Fagundes et al, 2012; Louis and Flint, 2013; De Palma et al, 2014; Llewellyn et al, 2014; Sison-Mangus et al, 2014; Stilling et al, 2014)

Summary

Laboratoire “Microorganismes

Edited by: Jonathan P. Zehr, University of California, Santa Cruz, USA Reviewed by: Peter R. Girguis, Harvard University, USA Marja Annika Tiirola, University of Jyväskylä, Finland Keywords: alteration of host behavior, manipulative parasite, microbiome, micro-organisms, host-parasite cross-talk

INTRODUCTION

BACKGROUND