Fig 2. Bumblebees were subjected to 5 day exposure to Imidacloprid and/or/none twice daily 670 nm.

Haemolymph was collected from antenna base and transferred to a haemocytometer as shown in the schematic (lower left). Haemocyte counts were used as a metric of immune health. Bumblebees were either exposed to Imidacloprid and or 670nm light. Exposures were for 5 days. Imidacloprid reduced haemocyte numbers (A), which was corrected with twice daily exposure to 670nm light (A). As with respiration we then asked what 670nm duration was needed for correction B. Bumblebees (≥ 20 bees per group) maintained on Imidacloprid were exposed to 670nm light for 0.5, 1, 5, 15 or 60mins. Controls (0) were unexposed. Exposure for 0.5 min had no impact, but 1 min exposure significantly increased haemocyte numbers. Longer exposures were similar. Bumblebees (≥ 22 bees per group) were exposed to a single 670nm for 1 min (C) and haemocytes counted at 24h intervals to determine duration of effect (C). (≥ 20 bees per group); 1 min exposures again restored haemocyte counts (D) over 48h (E), however, a decrease was observed from 96h post exposure (E), with no significance difference from the control observed afterwards. Abbreviations: *; p < 0.05. **; p < 0.01, ***; p < 0.005, ns; no significance, Imid; Imidacloprid.