Cover Image:

Tea-oil pollen toxic to honeybee larvae: When honeybees forage on the flowers of Camellia oleifera, a widely planted oilseed crop, their larvae die, but what kills the larvae remains controversial. Using bagging and caging studies, the authors show that birds effectively pollinate C. oleifera flowers. In contrast to the hypothesis of nectar toxicity, Zhang et al. (pages 2313-2316) propose that C. oleifera may have evolved toxic pollen to limit overexploitation of its pollen by bees. Toxicity tests indicated that C. oleifera pollen harmed honeybee larvae significantly more than pollen from Brassica napus, another oilseed crop, and C. oleifera pollen contains the insecticidal compound theasaponin. The cover shows simultaneous pollen presentation in a C. oleifera flower.