Meeting Abstract
Temperature has predictable, often non-linear, effects on many biological processes. Parasites of ectothermic hosts may have similar non-linear responses to temperature, however the effects of temperature on parasites are less well understood compared to that of free-living animals. We conducted lab experiments developing thermal optimum curves for reproduction and mortality in the parasitic castrator Loxothylacus panopaei in its mud crab host Eurypanopeus depressus. Parasitized and unparasitized hosts were exposed for 209 days to a range of temperatures (5 to 35° C in increments of 5° C) commonly experienced in the field. All parasitic larvae released from crabs were collected, quantified and measured; survival was recorded for both hosts and parasites. Reproductive output of the parasite was maximized at 20° C, with frequency of larval release occurring approximately every 7 days at 20° C and above. Time between releases was longer for temperatures below 20° C. Survival of uninfected hosts was maximized at 20° C, whereas survival of parasitized hosts was maximized at 10° C, creating an offset in the optimum between uninfected and infected hosts. This work reveals that temperature has a non-linear effect on parasite rates of survival and reproduction, and will need to be explicitly included in future models to obtain accurate predictions of infection as a response to ecosystem change.
