Behavioral thermoregulation of caterpillars is altered by temperature, but not parasitism: An empirical field study

Laboratory assays show that parasites often have lower heat tolerance than their hosts. But how physiological tolerances and behavioral responses of hosts combine to affect ecological interactions in heterogeneous field environments is largely unknown. We addressed this challenge using the model insect system braconid wasp parasitoid, Cotesia congregata, its caterpillar host, Manduca sexta. used experimental manipulations microclimate determine elevated daytime temperatures altered behavior, performance, survival host parasite. Our manipulation increased daily maximum on plants, but had negligible effects overall mean temperature. These resulted subtle, biologically relevant, changes physiology behavior parasitoid. found parasitism by did not significantly alter thermoregulatory while experimentally both parasitized unparasitized caterpillars be more frequently cooler microhabitats. Overall, we observe complete parasitoid mortality seen at extreme laboratory studies, gained insight into sublethal physiology. Climate change will biotic abiotic organisms face, here empirical experiments are important for understanding organismal response these new environments.