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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Animal Parasitic Diseases Laboratory » Research » Publications at this Location » Publication #321211
Title: Understanding host switching through ecological fitting

Author
item ARAUJO, SABRINA - Universidade Federal Do Parana
item BRAGA, MARIANA - Universidade Federal Do Parana
item BROOKS, DANIEL - Universidade Federal Do Parana
item AGOSTA, SALVATORE - Virginia Commonwealth University
item Hoberg, Eric
item VON HATHENTAL, FRANCISCO - Universidade Federal Do Parana
item BOEGER, WALTER - Universidade Federal Do Parana

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/11/2015
Publication Date: 10/7/2015
Citation: Araujo, S.B., Braga, M.P., Brooks, D.R., Agosta, S., Hoberg, E.P., Von Hathental, F., Boeger, W.A. 2015. Understanding host switching through ecological fitting. PLoS One. 10(10):e0139225.

Interpretive Summary: Concepts about the origin and evolution of host-parasite systems have been strongly tied to expectations about a central role for cospeciation or association by descent despite deep empirical evidence that indicates predominance of host switching over evolutionary and ecological time. Despite the observation that parasites are highly specialized, extensive field-based observations demonstrate that host-switching rather than cospeciation is the most important factor influencing the origin of these complex associations. A process termed ecological fitting has been proposed as the mechanism that allows host colonization to readily occur, and has implications for understanding the complexity of invasion and emergence of diseases caused by parasites. International collaborators including ARS scientists developed a simulations model to explore the process of host switching for parasites relative to multiple host resources. The model is consistent with a process for host range expansion which can occur readily and without prior evolution of novel genetic resources. The outcomes of the basic model as presented has considerable implications for understanding the potential for emerging disease in the context of ecological disruption. The model and interpretations for complex host-parasite systems will be significant for disease ecologists and epidemiologists in developing a nuanced understanding of the factors that serve to influence the distribution of pathogens and infection processes.

Technical Abstract: Despite the fact that parasites are highly specialized to their hosts, extensive empirical evidence demonstrates that host switching rather than co-speciation is the most important factor influencing the origin of host-parasite associations. Ecological fitting in sloppy fitness space has been proposed as a mechanism allowing host switching to occur readily. The causality of ecological fitting is tested herein using an individual based model of host-switching. The model considers a parasite species exposed to multiple host resources. Through time this population can evolve and switch among the exposed hosts. The model shows that host range expansion can occur readily and without the prior evolution of novel genetic capacities. It also produces variation in the size of the fitness space. The capacity for host colonization is strongly influenced by both fitness space and propagule pressure, but in different evolutionary stages. The simulations suggest that the process of co-adaptation may be accompanied initially by the temporary loss of less fit phenotypes. Further, parasites can persist for extended periods in sub-optimal hosts, and may colonize distantly related hosts mediated by a "stepping-stone" process.