Effect of the sesquiterpene lactone, helenin, on feeding rates and survival of the tundra redback vole Clethrionomys rutilus

The sesquiterpene lactone, helenin, acts as a feeding deterrent to redback voles, Clethrionomys rutilus . Animals avoided food containing at least 0.05% of helenin, and feeding rate and body weight of voles were sharply reduced when the helenin concentration was 1.5% or higher. Voles given food containing 3.0-7.0% of helenin died in 3-5 days. It is suggested that these effects of helenin are the result of its antifeedant property and subsequent starvation of animals as well as its interference with digestive processes. Helenin and other sesquiterpene lactones may play an important role in the defence of plants against herbivorous mammalian predators.