Data from: 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,
parasite release was higher at warm temperatures and increased temporarily
after infected snails were shifted to higher temperatures, particularly
for hosts acclimated to cooler temperatures. However, these effects were
transient, such that parasite release at warm temperatures declined
steadily over the seven days following the shift. Warmer temperatures also
increased snail mortality. 4. Parasite release was strongly influenced not
only by ambient temperature but also by the thermal history of the host.
Prior acclimation to warm temperatures reduced parasite release at warm
performance temperatures, contrary to the beneficial acclimation
hypothesis. Rather, the observed pattern was likely driven by: (1)
energetic costs of prolonged exposure to high temperatures (“thermal
stress”) or (2) parasites’ capacity to “store” infectious stages at cooler
temperatures. 5. The time-dependent nature of thermal effects on parasite
performance highlights the importance of considering the amplitude and
frequency of temperature variability for understanding future changes to
disease dynamics.