Effects of larval stage and diapause status on cold hardiness of emerald ash borer (Coleoptera: Buprestidae): implications for North American distribution limits

Authors: CHANDLER, JENNIFER - University Of Massachusetts, Amherst; Duan, Jian; TROTTER III, TALBOT - Us Forest Service (FS); ELKINTON, JOSEPH - University Of Massachusetts, Amherst

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/6/2026
Publication Date: 2/15/2026
Citation: Chandler, J.L., Duan, J.J., Trotter Iii, T.R., Elkinton, J. 2026. Effects of larval stage and diapause status on cold hardiness of emerald ash borer (Coleoptera: Buprestidae): implications for North American distribution limits. Journal of Economic Entomology. https://doi.org/10.1093/jee/toag006.
DOI: https://doi.org/10.1093/jee/toag006

Interpretive Summary: The emerald ash borer (EAB), an invasive beetle from Northeast Asia, has rapidly spread across North America since its discovery in Michigan in 2002, devastating ash tree populations. This study examines the beetle’s cold hardiness, revealing that factors such as larval stage, dormancy, prior cold exposure, and geographic origin influence its ability to survive harsh temperatures. These findings enhance predictions of EAB’s potential spread, helping forestry managers, conservationists, and policymakers develop better strategies to mitigate ecological and economic damage. Additionally, the research contributes valuable insights into how invasive species adapt to different climates.

Technical Abstract: The emerald ash borer (EAB), Agrilus planipennis Fairmaire, is an invasive pest of ash trees (Fraxinus spp) outside of its native range in Asia. The pace of EAB invasion of North America and Europe suggests that this beetle possesses extraordinary tolerance for a broad range of climatic conditions. While multiple studies have measured cold tolerance of overwintering EAB stages, none consider the effect of developmental stage or diapause on cold hardiness. In the present study, EAB cold hardiness, as measured by supercooling point (SCP) of lab-reared and field-collected larvae, differed with larval stage, diapause phase, and recent exposure to cold temperatures. Mature (non-feeding, J-shaped) larvae (JLs) were more cold-tolerant than immature (feeding) stages, whereas JLs in early and deep diapause phases were more cold-tolerant than those in post-diapause. The higher susceptibility of later overwintering stages to cold-induced mortality suggests that timing of extreme temperature events may determine overwinter survival of an EAB population. Furthermore, cold hardiness of JL and prepupae (a post-diapause stage) was influenced by the minimum temperature experienced in the preceding 2 weeks, however this relationship differs among stages and populations. Together, these findings indicate that developmental stage, diapause status, prior cold exposure, geographic origin all contribute to cold hardiness and the ability of EAB larvae to acclimatize to and survive cold temperatures. Understanding the relative impact of environmental and physiological factors on overwinter survival of EAB contributes to more accurate predictions of the potential geographic extent of EAB distribution in its invasive ranges.