Abstract/Summary

Previous laboratory studies have shown that diesel exhaust can differentially degrade the volatile organic compounds (VOCs) that constitute floral odors. Furthermore, in proboscis extension response studies honey bees have been shown to have reduced recognition to these degraded floral odors. In this study, we investigated whether flower odors exposed to diesel exhaust reduce foraging in free-flying bees and if flower color influences bees’ behavior. Therefore, we conducted a field study in which honey bees were trained to visit the locations of two arrays of artificial flowers. From the artificial flowers, honey bees were presented with floral VOCs combined with either fresh air or diesel exhaust, through different colored flowers (black, blue, red, and yellow). Honey bee visitation rate did not differ between volatiles delivered with fresh air or with diesel exhaust, suggesting that revisitation of previously rewarding flower patches may be unaffected by air pollution. We also observed a significant interaction between treatment and color: blue flowers were more attractive when volatiles were delivered with diesel exhaust, which was the other way around for red and black and played no role in yellow flowers. Generally, honey bee foraging behavior seemed to be influenced by their previous experiences.