Nicotine a medicine for parasitized bumblebees

A medicine for ill bumblebees (Bombus terrestris) but a poison for healthy ones, researchers from Queen Mary University of London and Royal Holloway, University of London found that bumblebees infected with the trypanosome gut parasite Crithidia bombi preferred nicotine-laced nectar.  The nicotine had a benefit for infect bees: antimicrobial secondary metabolites which delayed the infection by a few days, though it didn't clear the infection entirely nor extend the overall life expectancy.  When healthy bees consumed nicotine-laced nectar for long periods reduced their life expectancy, an effect not observed in infected bees.

large earth humble bee (Bombus terrestris) by Whitney Cranshaw, Bugwood.org

To read about the research: Bumblebees use nicotine to fight off parasites
Images of Bombus terrestris: Bombus terrestris