Heat stress alters Drosophila locomotor behaviors in a sex-specific manner: a machine learning analysis.

Global warming is increasing extreme heat events posing a serious threat to insect populations the cornerstone of terrestrial ecosystems. While studies focus on heat stress effects on reproduction its immediate and sex specific effects on locomotor behavior a key determinant of survival remain poorly understood. This study investigated behavioral responses in the model organism Drosophila melanogaster under simulated heat wave conditions. Flies were exposed to acute sublethal heat stress at 37 ℃ for 30–60 min. Using the deep learning framework SLEAP to track body parts, we precisely quantified kinematic parameters. Analysis revealed distinct sex-specific patterns. Male Drosophila showed transient hyperactivity to short-term heat followed by significant gait impairment evidenced by reduced step length after prolonged exposure. Females showed greater initial tolerance and their activity declined significantly only after extended exposure. These findings indicate that even brief acute heat stress profoundly affects Drosophila locomotor performance in a sex-dependent manner. This sex difference suggests heat waves may de-synchronize male and female behaviors, such as courtship and foraging, thereby increasing the risk of reproductive failure. Using Drosophila, this study demonstrates that climate warming may alter insect population dynamics by disrupting fundamental behavioral patterns. The machine learning based gait quantification offers a novel approach to assess the sublethal effects of climate change providing key insights into how rising temperatures threaten biodiversity.