Meeting Abstract
Global environmental change can influence the interactions between hosts and parasites, with consequences for parasite development, transmission and life cycle completion rates. Here we present results from recent experimental studies examining how increased temperature alters host-parasite interactions across the life cycle of the parasitic cestode Schistocephalus solidus. The effects of temperature on the growth of larval parasites in stickleback hosts were dramatic. Over a 16-week post-infection period, a 5C temperature increase generated a fourfold increase in plerocercoid growth rate in experimentally infected fish, with all parasites reared in fish held at 20C developing infective worms, compared to none held at 15C. Furthermore, infected fish exhibited behavioural preferences for warmer temperatures, potentially generating a feedback loop accelerating parasite growth. Following the in vitro culture of adult worms, individual copepods (the 1st intermediate hosts of the parasite) were exposed to a controlled dose of S. solidus parasites and held under controlled temperatures. Infectivity of the parasite was quantified, and the subsequent growth rates of procercoids in host copepods was tracked over 6 weeks post-infection. Our results provide detailed information on the role of temperature dependent development of key developmental life stages of this parasite life cycle, and give insight into how life cycle completion rates might be altered under environmental warming. Our studies on this experimentally amenable model system demonstrate that anthropogenic global changes have considerable potential to influence the outcome of host-parasite interactions, with significant consequences for disease phenotypes and for life cycle completion rates under perturbed environments.
