Behavioral Effects of Nicotine Exposure and Withdrawal on Drosophila melanogaster Larvae

Nicotine addiction has become an increasingly major problem within all age groups, especially teenagers. This study investigates the behavioral effects of nicotine on Drosophila melanogaster larvae across conditioning, exposure, and withdrawal phases. Larvae were divided into five groups: a negative control (0% nicotine), a conditioned group exposed to 0.5 mL of 0.01% nicotine for 48 hours, and a sudden exposure group subjected to acute treatment. Both conditioned and sudden groups were subdivided into high-dose (2 mL, 0.01%) and low-dose (1 mL, 0.01%) subgroups. Over a two-hour observation period, we recorded locomotion time, stillness, movement speed, feeding, sleep, and responses to light and touch. Larval size was measured before and after each phase. During conditioning, Group 2 larvae showed moderate motion and signs of tolerance. During exposure, ANOVA revealed a highly significant group effect for motion time (F(2, 9) = 192.000, p < 0.001), with Tukey HSD showing that sudden-exposure larvae moved on average 40.0 minutes longer than both conditioned and control groups (p < 0.001), and for speed (F(2, 9) = 49.024, p < 0.001) with sudden-exposure larvae significantly faster than the other groups. Withdrawal phase analyses showed significant motion reductions (F(2, 9) = 39.000, p < 0.001), with sudden-exposure larvae moving 15.0 minutes less than conditioned (p = 0.0003) and 20.0 minutes less than controls (p < 0.001), as well as slower withdrawal speeds (F(2, 9) = 15.356, p = 0.0013). These results confirm that chronic low-dose nicotine conditioning mitigates—but does not eliminate—acute behavioral disruptions and withdrawal suppression seen after sudden exposure, offering quantitative insight into the neurobehavioral dynamics of nicotine tolerance and sensitivity in Drosophila.