Meeting Abstract
A primary goal in ecophysiology is to understand how temperature influences physiological traits, behavior, and species distributions. Although many studies focus on thermal performance of single species, determining responses to climate change will depend on understanding how temperature affects interactions among species. Small ectotherms, which make up the majority of Earth’s biomass, are an experimentally tractable group of organisms in which to examine the temperature-dependence of species interactions. Here, we take an insect’s-eye-view of temperature to understand i) how micro-scale temperature is related to insect thermal tolerance and ii) how thermal tolerance differs between a parasitoid wasp and its caterpillar prey. We used the aspen leaf miner-parasitoid wasp system, an emerging model for investigating the thermal ecology of parasites and hosts. We predicted that leaf miners and wasps raised on leaves exposed to the sun would have higher heat tolerance than those from shaded leaves. We also predicted that the sedentary leaf miners, which are unable to thermoregulate using behavior, would have higher heat tolerance than their free-flying predators. We tested this prediction by measuring upper lethal limits in wild-caught leaf miners and adult wasps from ‘sunny’ and ‘shaded’ aspen leaves. Our results revealed no effect of sun versus shade, but caterpillars had higher heat tolerance than their predators. We discuss these results in the context of ecological theory about predator-prey interactions and response to climate change.
