Domestic composters as winter reservoirs for the invasive pest Drosophila suzukii in temperate climates
Romain Georges, Théo Laguilliez, Damien Gourmelon, Hervé ColinetAbstract
BACKGROUND
Drosophila suzukii is an invasive pest established worldwide, including in temperate regions with harsh winters. As a chill‐susceptible species, its overwintering success relies on migration to favorable microhabitats and phenotypic plasticity. Overwintering forms are more chilling tolerant and exploit suboptimal resources like decomposing matter, while non‐overwintering forms prefer ripe fruits. The rise of domestic composting has increased compost sites in urban and residential areas, yet their role as winter refuges for D. suzukii remains unexplored. We monitored nine experimental composters over 2 years using emergence traps and continuous temperature recording.
RESULTS
A total of 7377 D. suzukii adults emerged year‐round, confirming sustained colonization and development even in winter. Abundance showed a bimodal pattern, peaking in spring and late autumn‐early winter. Composter composition influenced D. suzukii fly numbers, but all treatments supported populations throughout the year. Minimum ambient temperature was the main predictor of abundance, with higher temperatures leading to an increase in the number of emerging flies; internal thermal buffering likely protected immature stages from lethal cold. Critically, newly emerged D. suzukii adults were collected during winter, providing evidence of pre‐imaginal development during winter. This supports the idea that D. suzukii uses a mixed overwintering strategy involving both adult dormancy and slow immature development.
CONCLUSION
Our findings reveal that domestic composters act as effective microhabitats and potential overwintering reservoirs for D. suzukii . As composting policies expand across Europe and US, these anthropogenic environments may facilitate pest persistence and reinfestation in nearby crops. Thus, integrating pest risk considerations into waste management policies is crucial for developing effective and sustainable control measures against D. suzukii . © 2026 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.