A new study of possible self-medicating behavior in bumble bees conducted by researchers at the University of Massachusetts Amherst reports that a once-promising finding was not supported by further experiments and analysis.
Doctoral candidate Evan Palmer-Young and his advisor, evolutionary ecologist Lynn Adler, had reported in 2015 that a common parasitic infection of bumble bees was reduced when the bees fed on anabasine in sugar water. Anabasine is a natural alkaloid, nicotine-like chemical found in plant nectar. The researchers had hoped their finding was evidence that bees may use “nature’s medicine cabinet” to rid themselves of the intestinal parasite Crithidia bombi, which can decrease the survival of queen bees over the winter and hamper the success of young colonies in the spring.
But as they report in the current issue of PLOS ONE, those results were not borne out with further investigation. “Although uninfected bees in our experiments were not adversely affected by alkaloid-containing diets, anabasine had deleterious effects on infected bees. This is the first report of exacerbation of floral alkaloids’ negative effects by Crithidia infection,” they write.
Further, “This exacerbation is consistent with a growing body of work that suggests the negative effects of combined stressors – including infection, diet quality, and consumption of pesticides – on pollinator health and that widespread infection could have consequences for bees’ ability to tolerate phytochemicals.”