Honey Bee Pollination of Camellia oleifera and Mitigation of Toxic Crop Nectar

Tea oil tree (Camellia oleifera), a woody oil crop native to Southern China, relies on insect pollination for fruit and seed production. However, its nectar is toxic to honey bees (Apis spp.) due to their inability to digest the oligosaccharide present in the nectar. This toxicity raises concerns about the trade-off between the benefits of pollination and the risks posed by exposures to toxic nectar. We aimed to investigate whether tea oil tree yield is enhanced by honey bee pollination, while also examining the impact of nectar toxicity and exploring potential mitigation methods. We evaluated the fruit set, seed yield, and oil quality of the crop with or without eastern honey bee (A. cerana) pollination during 2019-2022. We also characterized nectar oligosaccharide compositions collected from both flowers and bee hives. We administered α-galactosidase (an enzyme to promote oligosaccharide digestion) onto bee larvae fed with crop nectar. We found that A. cerana could significantly enhance fruit set and seed yield. The administration of α-galactosidase could enhance larval survivorship challenged by nectar toxicity. The effectiveness of honey bee pollination can vary between years, with warmer temperatures significantly enhancing honey bee pollination benefits. The results suggest that a decision to use honey bees for pollinating tea oil trees should involve consideration of the impact of local weather conditions, as low temperatures may compromise pollination benefits while increasing risks posed by toxic nectar. The administration of digestive enzymes to honey bees shows potential for mitigating natural toxins in tea oil tree nectar.