Multidimensional behavioral profiling uncovers centrifugal hyperactivity induced by the neonicotinoid dinotefuran in Drosophila melanogaster.

Dinotefuran is a widely used third-generation neonicotinoid insecticide, yet its sublethal effects on non-target insect behavior remain poorly resolved. We used the deep-learning tracking framework SLEAP to quantify locomotor and spatial responses of Drosophila melanogaster larvae after 72 h of exposure to nominal dinotefuran concentrations of 0, 10, 50, and 100 μM. Kinematics, velocity distributions, trajectory geometry, spatial redistribution, inter-individual spacing, and principal component analysis (PCA) were integrated. Compared with control larvae, larvae exposed to 50 and 100 μM dinotefuran showed increases in mean linear velocity, respectively, spent a greater proportion of the recording time in the high-speed range, and explored a larger area. Although mean angular velocity did not differ significantly among groups, exposed larvae spent more time at low angular velocities and less time at medium-to-high angular velocities. Exposure increased trajectory straightness, radius of gyration, mean squared displacement, outward redistribution, and inter-individual spacing. PCA supported this multivariate response: PC1 and PC2 explained 52.1% and 16.6% of the variance, and the higher-concentration groups shifted toward higher PC1 scores associated with locomotor activity and spatial exploration. These findings show that dinotefuran alters multiple dimensions of larval behavior and support high-resolution behavioral profiling for assessing sublethal pesticide effects.