Nectar—but not for parasites

Abstract

Pollination Bumble bees are vulnerable to parasitism by a flagellated trypanosome (some species of which are important human pathogens). The parasite Crithidia bombi , in combination with environmental stresses, can promote declines in bumble bee populations by reducing foraging and reproductive success. Koch et al. developed a chromatographic pipeline to efficiently search for natural products in single-species honey that might protect pollinators. Of the four most bioactive species the authors found, nectar from Calluna vulgaris , an iconic moorland plant in the United Kingdom, contains a compound called callunene, which promotes flagella shedding by the parasite, eliminating its ability to attach to the bumble bees' gut epithelial cells and cause infection. If bees ingest C. vulgaris nectar in high amounts, they are protected from infection, but if they are already infected, there is no curative effect. Curr. Biol. 29 , 3494 (2019).