Microbiomes, plausible players or not in alteration of host behaviour

Abstract

Recent surveys of microbiomes indicate that the communities of commensal and symbiotic micro-organisms living in guts are involved in maturation and functioning of animal nervous systems. Therefore, when a manipulative parasite colonizes a host tissue to ensure its growth and the completion of its life cycle, a plausible assumption is that the molecular crosstalk taking place between the manipulative parasite and the invaded host could be promoted or disturbed via the neuroactive molecules synthesized by the gut microbiome. These molecules can pass through the enteric nervous system to interact with the host nervous system. As a consequence, the gut microbiome of living organisms is likely to have additive effects on the host's central nervous system, altering its behaviour or, alternatively, the effector molecules of the manipulative parasite could be modulated by the neuroactive molecules of the gut microbiome. Understanding and such crosstalks and interactions involved in temporal sharing of host niches by gut microbiomes and manipulative parasites is an important research focus. Here, we present recent studies on the effects of gut microbiomes on host behaviours. Finally, focusing on organisms living in aquatic ecosystems, we discuss the concepts and methods needed to decipher the role of gut microbiomes on the manipulation of host behaviours by parasites in aquatic ecosystems.