Global warming modifies long-distance migration of an agricultural insect pest

Abstract

Global warming has pronounced impacts on the physiology, development and behavior of multiple organisms and affects the geographical distribution of arthropods. Yet, little is known about how a heightened ambient temperature influences migratory insects that are globally relevant to agriculture. Here, we quantified the extent to which increases in surface temperature, over the span of 3 decades, impact long-distance migration processes of the globally important cutworm Agrotis ipsilon (Lepidoptera: Noctuidae). Multi-year monitoring in China indicated how high-altitude migrants of A. ipsilon annually attain two distinct seasonal peaks, i.e., during spring and summer. Stable isotope analyses of field-caught individuals further showed a gradually shifting origin of migrant populations, with ground-level A. ipsilon abundance partially reflecting population levels of high-altitude migrants. Over a 27-year time period, respective population peaks for overwintering and the first-generation A. ipsilon adults were reached 17 and 8 days earlier in the year. Also, the northern border of the A. ipsilon potential overwintering area progressed northward by 58–232 km, and its migration range expanded by 708 km. Our work reveals how a progressively increasing surface temperature affects long-distance migration of a cosmopolitan agricultural pest and alters the population phenology and geographical distribution of A. ipsilon in eastern Asia. Global warming thus influences ecological dynamics in temperate agro-ecosystems and can magnify the economic impacts of long-distance migratory pests.