Dr. Daniel A. Hahn


Seasonal Adaptation: The changing of the seasons is a common stressor for ectotherms, including beneficial and damaging insects. Thus insects have evolved many adaptations to mitigate seasonal stress and to synchronize their lifecycles with favourable times. As global climates change, the timing of the onset and end of winter relative to growing seasons is changing and predictions call for greater climatic variability at the seasonal shoulders. Both of these factors can strongly affect ectotherm populations. As a product of climate change, some damaging insects are projected to increase their ranges, population sizes, and number of generations per year while some beneficial insects are at greater risk for extinction. We study the physiological and genetic mechanisms of adaptation in seasonal dormancy (diapause) and seasonal stress tolerance with an eye to predicting potential winners and losers in the context of climate change. 

Adaptive Radiation in Insect-Host Relationships: Phytophagous insects represent a large slice of animal diversity and host-plant specialization has been shown to increase diversification. Most work on host-plant specialization focuses on host plant chemistry, specifically nutrition and defences, but seasonal synchrony between insect herbivores and their host plants is also a critical dimension of diversification. We study how the physiological and genetic mechanisms underlying life history timing may interact with host-plant feeding and host-choice in phytophagous insects to facilitate or constrain diversification of insect herbivores.

Applications to Pest Management: We are interested in using our knowledge about the physiological and genetic mechanisms of stress hardiness and seasonal biology to improve biologically based, environmentally friendly methods of pest management. We are particularly interested in: 1) improving the performance of sterile males in the sterile insect technique, 2) improving non-pesticidal post-harvest phytosanitary treatments for commodities, 3) improving the rearing of biological control agents including enhancing storage and shelf-life to suppor the biological control industry, and 4) applying knowledge of seasonal biology to improve the selection and performance of biological control agents in the field.


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Associate Professor, Evolutionary Physiology