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. 2013 May 31;8(5):e64920. doi: 10.1371/journal.pone.0064920

Figure 1. Survival plot of time to loss of righting reflex, and barplot of amount of locomotion for bees acutely and repeatedly treated with cocaine.

Figure 1

Numbers indicate sample size per group. A. Survival plot of time to loss of righting reflex after acute treatment with vehicle control, 10 µg of cocaine, or 20 µg cocaine. The loss of righting reflex to cocaine administration occurred significantly earlier in cocaine treated groups than controls (Survival analysis: Kaplan-meier log-rank test: χ 2 = 32.2, p<0.001, n = 10 per cocaine group; n = 30 for vehicle control). Pair-wise comparison showed that all groups differed from each another (10 µg vs DMF: χ 2 = 10.5, p = 0.0012; 20 µg vs DMF: χ 2 = 30.1, p<0.0001; 10 µg vs 20 µg: χ 2 = 4.9, p = 0.0262). B. Survival plot of time to loss of righting reflex after being treated with 10 µg of cocaine following seven pretreatments with either 3 µg of cocaine, vehicle- or sham control. Time to loss of the righting reflex after administration of 10 µg cocaine was delayed in bees repeatedly pretreated with 3 µg of cocaine, compared to controls never treated with cocaine prior to the challenge dose (Survival analysis: Kaplain-meier log-rank test: χ 2 = 18.4, p = 0.0001, n = 26 per group). Pair-wise comparison showed that both controls differed from cocaine treated bees (Sham: χ 2 = 7.5, p = 0.0060; DMF: χ 2 = 18.9, p<0.0001). Control groups did not differ from each other (Sham vs DMF: χ 2 = 2.5, p = 0.1110). C. Amount of locomotion twenty mins after administration of vehicle control or 10 µg cocaine. Locomotion is reduced by a large cocaine dose (Mann-Whitney test: U = 22, p = 0.037). D. Amount of locomotion twenty min after administration of 10 µg cocaine after seven repeated treatments with 3 µg cocaine, or sham or vehicle control. The bees pretreated with 3 µg moved significantly after treatment with a 10 µg cocaine dose than the controls never treated with cocaine (ANOVA: F2,85 = 4.834, p = 0.011; Tukey’s multiple comparison between controls and cocaine: p = 0.012, between controls: p = 0.969).