Pest population dynamics are related to a continental overwintering gradient

Authors: LAWTON, DOUGLAS - North Carolina State University; HUSETH, ANDERS - North Carolina State University; KENNEDY, GEORGE - North Carolina State University; MOREY, AMY - University Of Minnesota; HUTCHISON, WILLIAM - University Of Minnesota; REISIG, DOMINIC - North Carolina State University; Dorman, Seth; DILLARD, DESHAE - North Carolina State University; VENETTE, ROBERT - Us Forest Service (FS); GROVES, RUSSELL - University Of Wisconsin; Adamczyk, John; BARBOSA DOS SANTOS, I - University Of Florida; BAUTE, TRACEY - Omafra (ONTARIO MINISTRY OF AGRICULTURE & FOOD/RURAL AFFAIRS); BROWN, SEBE - University Of Tennessee; BURKNESS, ERIC - University Of Minnesota; DEAN, ASHLEY - Iowa State University; DIVELY, GALEN - University Of Maryland; DOUGHTY, HELENE - Virginia Tech; FLEISCHER, SHELBY - Pennsylvania State University; GREEN, JESSICA - Oregon State University; GREENE, JEREMY - Clemson University; HAMILTON, KRISTA - Wisconsin Department Of Agriculture; HODGSON, ERIN - Iowa State University; HUNT, THOMAS - University Of Nebraska; KERNS, DAVID - Texas A&M University; LEONARD, B - Louisiana State University Agcenter; MALONE, SEAN - Virginia Tech; MUSSER, FRED - Mississippi State University; OWENS, DAVID - University Of Delaware; PALUMBO, JOHN - University Of Arizona; PAULA-MORAES, SILVANA - University Of Florida; PETERSON, JULIE - University Of Nebraska; RAMIREZ, RICARDO - Utah State University; RONDON, SILVIA - Hermiston Agricultural & Extension Center; SCHILDER, TRACY - Wisconsin Department Of Agriculture; SEAMAN, ABBY - Cornell University; SPEARS, LORI - Utah State University; STEWART, SCOTT - University Of Tennessee; TAYLOR, SALLY - Virginia Tech; TOWLES, TYLER - Louisiana State University; WELTY, CELESTE - The Ohio State University; WHALEN, JOANNE - University Of Delaware; WRIGHT, ROBERT - University Of Nebraska; ZUEFLE, MARION - Cornell University

Submitted to: Proceedings of the National Academy of Sciences (PNAS)
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/6/2022
Publication Date: 9/6/2022
Citation: Lawton, D., Huseth, A., Kennedy, G., Morey, A., Hutchison, W., Reisig, D., Dorman, S.J., Dillard, D., Venette, R., Groves, R., Adamczyk Jr., J.J., Barbosa Dos Santos, I., Baute, T., Brown, S., Burkness, E., Dean, A., Dively, G., Doughty, H., Fleischer, S., Green, J., Greene, J., Hamilton, K., Hodgson, E., Hunt, T., Kerns, D., Leonard, B., Malone, S., Musser, F., Owens, D., Palumbo, J., Paula-Moraes, S., Peterson, J., Ramirez, R., Rondon, S.I., Schilder, T., Seaman, A., Spears, L., Stewart, S., Taylor, S., Towles, T., Welty, C., Whalen, J., Wright, R., Zuefle, M. 2022. Pest population dynamics are related to a continental overwintering gradient. Proceedings of the National Academy of Sciences (PNAS). 119(37). Article e2203230119. https://doi.org/10.1073/pnas.2203230119.
DOI: https://doi.org/10.1073/pnas.2203230119

Interpretive Summary: Climate change-driven expansion of pest distributions will threaten agriculture on a global scale. Winter soil temperature is a known limiting factor for pest persistence in higher latitudes. However, few studies have connected the overwintering success of soil-dwelling insects with long-term population datasets to investigate how climate change may affect future pest distributions and populations. Here, we present models demonstrating how greater overwintering survival will likely expand the range of a serious insect pest, the corn earworm (Helicoverpa zea Boddie), an economic pest in field crop systems across North America. Using a long-term monitoring database, we demonstrate corn earworm populations are driven by one of three overwintering zones (Southern Range, Transitional Zone, Northern Limits). Seasonal populations were initially detected in the Southern Range, where they experienced multiple population peaks. All three zones experienced a final peak between late July (Southern Range) and mid-August to mid-September (Transitional Zone and Northern Limits). The Transitional Zone and Northern Limits experienced smaller and fewer peaks since 1995. The Southern Range expanded by 3% since 1981 and is projected to increase twofold by 2099, whereas other zones have and likely will continue to decrease in area. These changes suggest larger populations may persist at higher latitudes in the future due to reduced low-temperature lethal events during winter. Because corn earworm is a highly migratory pest, predicting when populations accumulate in one region can inform lagged population development in other regions. We also highlight the need for projected soil temperature data based on climate change scenarios. To ensure stable crop production without substantial increases in chemical inputs, insect pest range shifts must be anticipated to allow the development of management solutions that mitigate crop loss in expansion areas.

Technical Abstract: Overwintering success is an important determinant of arthropod populations that must be considered as climate change continues to influence the spatiotemporal population dynamics of agricultural pests. Using a long-term monitoring database and biologically relevant overwintering zones, we modeled the annual and seasonal population dynamics of a common pest, Helicoverpa zea (Boddie), based on three overwintering suitability zones throughout North America using four decades of soil temperatures: the southern range (able to persist through winter), transitional zone (uncertain overwintering survivorship), and northern limits (unable to survive winter). Our model indicates H. zea population dynamics are hierarchically structured with continental-level effects that are partitioned into three geographic zones. Seasonal populations were initially detected in the southern range, where they experienced multiple large population peaks. All three zones experienced a final peak between late July (southern range) and mid-August to mid-September (transitional zone and northern limits). The southern range expanded by 3% since 1981 and is projected to increase by twofold by 2099 but the areas of other zones are expected to decrease in the future. These changes suggest larger populations may persist at higher latitudes in the future due to reduced low-temperature lethal events during winter. Because H. zea is a highly migratory pest, predicting when populations accumulate in one region can inform synchronous or lagged population development in other regions. We show the value of combining long-term datasets, remotely sensed data, and laboratory findings to inform forecasting of insect pests.