Resource partitioning and tolerance of monoterpenes in four species of spruce aphid

The tolerance of four species of aphids to myrcene was assessed by measuring the mortality of aphids exposed to different amounts of this monoterpene.Each species was found to exhibit significantly different levels of tolerance to myrcene.which is explicable in terms of the likely concentration of myrcene at the feeding site of each species. Tolerance to monoterpenes maybe specific only to those encountered in high concentrations at the feeding site.whereas others are found to be toxic.This suggests that each species has become physiologically adapted to tolerate different levels of the specific monoterpenes that occur in the microhabitats they occupy.