Using museum specimens to understand distributional changes of agricultural pests

In the face of anthropogenic climate change, the challenge for pest risk assessment is in developing rigorous predictions of what climate conditions will exacerbate pest problems.  At the same time, changes in biotic interactions through time—particularly with wild and cultivated host plants—are likely to influence pest populations as well.  The analysis of historical data—linking data on pest and host distributions to climate data—may elucidate relationships between climate change, biotic interactions, and changes in pest population range.  The artichoke plume moth, Platyptilia carduidactyla [Lepidoptera: Pterophoridae], is a specialist on thistles and has historically been an important pest of artichokes (Cynara scolymus) throughout California, USA.  Through the combination of museum collections of P. carduidactyla and host plants, historical climatic and land-use data, and species distribution modelling, we are investigating how P. carduidactyla has responded to (1) historical climatic change, (2) expansion of artichoke production, and (3) introduction of exotic thistle host species Cirsium arvense and C. vulgare.  In this talk, we will present preliminary results of our analyses.  By studying the simultaneous responses of pest populations to historical climate change and changes in host plants, we aim to improve risk assessments of pest outbreaks associated with climatic and land-use change in the future.