Bill Nelson, Queen’s University
Host: Marty Krkosek
The schedules of development, survival and fecundity that define life history are well described for a good number of organisms. We can often anticipate how life histories respond to changes in the environment, such as temperature or competition for food, which provides the building blocks to understand how populations may respond to real-world environmental changes. However, scaling up these life-history schedules to predict ecological dynamics has proven comparatively difficult. In this talk, I will present our recent work studying the mechanisms that generate outbreak cycles in the tea tortrix (Adoxophyes honmai), which is an agricultural pest of tea plantations. Starting with a remarkable set of time-series data that spans over 51yrs and 200 outbreaks, the talk will look at insight gained from statistical approaches, laboratory life-history experiments and development of population model. Unexpectedly, the model predicts that insect populations will cross a Hopf bifurcation from stability to sustained cycles as temperature increases. To test these predictions, I will show results from a laboratory-based population experiment across a gradient of temperature, and some preliminary results from a field-based experiment looking at one of the classic hypotheses about seasonal outbreaks. Our results reveal that temperature alters system stability in this multivoltine insect, and suggest a different approach to pest control.