Pest population dynamics are related to a continental overwintering gradient

Area of Science:

• Agricultural Entomology
• Climate Change Ecology
• Population Dynamics Modeling

Background:

• Overwintering success is critical for arthropod pest population dynamics, especially under climate change.
• Helicoverpa zea (Boddie) is a significant agricultural pest whose population dynamics are influenced by overwintering conditions.
• Understanding spatiotemporal population dynamics is crucial for managing agricultural pests.

Purpose of the Study:

• To model the annual and seasonal population dynamics of Helicoverpa zea across North America.
• To assess the impact of climate change on overwintering suitability zones for H. zea.
• To forecast future population trends and range expansion of H. zea.

Main Methods:

• Utilized a long-term monitoring database spanning four decades.
• Modeled population dynamics based on soil temperatures within three defined overwintering suitability zones (southern, transitional, northern).
• Integrated remotely sensed data and laboratory findings with long-term datasets.

Main Results:

• Helicoverpa zea population dynamics exhibit hierarchical structuring across continental zones.
• The southern overwintering range of H. zea has expanded by 3% since 1981 and is projected to double by 2099.
• Warmer winters are associated with reduced low-temperature lethal events, suggesting potential for increased H. zea populations at higher latitudes.

Conclusions:

• Climate change is altering the overwintering suitability zones for Helicoverpa zea, leading to range expansion.
• Future climate scenarios predict a decrease in transitional and northern overwintering zones but an increase in the southern zone.
• Forecasting pest populations requires integrating long-term ecological data, climate information, and biological insights.