Authors

Discussion

The effects of anthropogenic global warming on host-parasite interactions can have considerable ecological implication and have gained much attention. In addition, the consequences of multiple stressors associated with global temperature change has also been subject to recent study. However, far less is known about the interaction between temperature change and altered food availability on subsequent host-parasite biology. Here, we outline a study designed to examine the effects of interaction between global warming and altered ration of the three-spined stickleback fish host - Gasterosteus aculeatus on the fitness of a cestode parasite – Schistocephalus solidus. Sticklebacks were either parasite-exposed or sham exposed by feeding with infected or non-infected copepods respectively and held at either 15˚C or 20˚C for eight weeks. During this period fish were fed either 8% or 16% body weight per day. Every two-week fish was weighed to recalculate food ration. At the end of study, the infection status of all fish was determined, and mass of plerocercoids was quantified and indices of fish health and immune status calculated. The plerocercoids of S. solidus recovered from infected fish were cultured by using in vitro techniques to measure parasite fecundity. Our results show host’s growth and body condition were enhanced at cooler temperature, whereas warmer temperature favours accelerated growth of S. solidus plerocercoids and bigger worms have produced more eggs. The effects of host ration found to be non-significant on host parasite biology, thus suggesting that 8% body weight was adequate to sustain parasite growth even at the warmer/higher temperatures. Furthermore, our results indicate that the effects of warmer temperatures on parasite growth may be unlikely to be diminished even if available food is reduced. In this talk I will discuss the possible implications of these findings on the ecology of host-parasite interactions in changing environment.