Ecology, epidemiology and evolution in a gut trypanosomatid parasite of bumble bees with multiple host species

Abstract

I have empirically explored the impact of different factors on the coevolution of a multihost-parasite system consisting of a gut trypanosomatid and its bumble bee host species assemblage. I have studied the potential impact of different factors on the epidemiology of the parasite, and thus, I have explored both the within host and among host species dynamics: host heterogeneity (host nutrition, host sex, host caste, host species), the potential for parasite intra- and inter-specific transmission, and the genetic structure of the parasite population at both geographical and temporal scales. While most of these factors have been previously suggested as determinant of the coevolutionary dynamics between host and parasites other factors were studied as a logical extension of some findings or because they are potentially important to further understand the evolution of this system. I found that: (i) the parasite has been forced to adopt a generalist strategy; (ii) the driving force in this multihost-parasite system is the host; and (iii) queens are responsible for the evolution of parasite generalism. I further discuss the consequences of my findings in other social insect systems.