Meeting Abstract
Climate change is expected to increase average temperatures and alter precipitation across the world, which should have disproportionate impacts on ectothermic animals. If metabolic rates increase with temperature, multiple cascading alterations can occur in addition to increased food consumption such as elevated movement rates and distances, growth, and fecundity. However, most ectotherms have an optimal temperature above which they suffer physiological stress unless they can shift their thermal tolerance range. We observed the effects of temperature on the feeding rate of two terrestrial slug species: Ariolimax columbianus (banana slug, native to Pacific Northwest) and Arion rufus (invasive slug, native to Europe). Individuals of both of these nocturnal species were exposed to 5°C (average spring night temperature), 10°C (average summer night temperature), and 20°C to determine the impact of temperature on consumption rates. We conducted these experiments in two summers: one with aberrantly high temperatures and drought, another with more typical temperatures and mild drought. We also investigated whether short term (7 day) exposure to either 5°C or 20°C before testing allowed the animals to acclimate and elevate their experimental feeding rates. Additionally, we tested the effect of humidity and soil moisture level on feeding rates. Because slugs are extremely sensitive to desiccation and regulate most moisture gain/loss through the foot, we expected feeding rate to increase with humidity and soil moisture content. Comparing results across two species of slugs, especially as one is an invader and the other is a native species with a highly restricted range in terms of biogeography and microhabitat, will provide insight as to how anticipated climate changes will impact the local molluscan fauna, as well as perhaps local ectotherms in general.
