Mechanisms responsible for assembly of aquatic communities by condition-dependent dispersal

Abstract

Dispersal is a process that determines ecological and evolutionary patterns, and it is intimately associated with habitat selection. The movement behaviour and dispersal of individuals is a condition-dependent and, informed processes, in which the dispersers respond to habitat quality and resources availability of the natal site and environment. Yet, the use of informations such as density, chemicals or abiotic conditions is highly advantageous during all three stages of dispersal (emigration, transition, immigration) and can be used to trigger dispersal and movement decisions. Although many studies have shown that the dispersal is a condition-dependent process, the responsible triggers for dispersing individuals between their birthplace and a new habitat are still not well understood. Therefore, we aim to investigate the triggers involved in the dispersal dynamics and habitat selection using a host-parasite system as a model and, focusing on free-swimming ciliated larvae (i.e. oncomiracidia) as a dispersing stage of the ectoparasite species. Our prediction is that the variation in the total abundance, richness, and dissimilarity of ectoparasite species among the parasitized and non-parasitized hosts can be explained and estimated by the measurable characteristics of the host, such as size, density, and nutritional status. Our ideas are based on the hypothesis of host heterogeneity that the individual host within a species can vary in relation to the resources and risks that they offer during the colonization of the new parasites in adult and larval form. In this case, the host quality (i.e., analogous to habitat patches for parasites) can be used as a key feature in predicting the dynamics of ectoparasite dispersal among hosts. Thus, we will use a tilapia-monogenoidea system as our experimental model to test the hypothesis that the dispersal of oncomiracidia is condition-dependent and, to bring new ideas to light on the role of dispersal in the assembly of aquatic communities with strong interaction between species. (AU)