How temperature shifts affect parasite production: testing the roles of thermal stress and acclimation

1. Changes in the magnitude and frequency of temperature shifts with climate change will influence species interactions if species have differential acclimation responses. For example, if parasites acclimate to temperature shifts faster than their hosts, as might be expected due to their smaller sizes and faster metabolisms, temperature variability could lead to increased infection. However, this assumption might not hold if benefits of acclimation are counteracted by energetic costs or thermal stress, underscoring the need for empirical efforts to assess how temperature variability will influence host-parasite interactions. 2. We used an array of replicate incubators to test how temperature shifts from five acclimation temperatures (13-25°C) to five performance temperatures (16-28°C) influenced release of infective stages by the trematode parasite, Ribeiroia ondatrae, from its snail intermediate host (Helisoma trivolvis) at four time points after a temperature shift. 3. Initially, para...