RESOURCE PARTITIONING AND TOLERANCE OF MONOTERPENES IN 4 SPECIES OF SPRUCE APHID

The tolerance of four species of aphids to myrcene was assessed by mea suring the mortality of aphids exposed to different amounts of this mo noterpene. Each species was found to exhibit significantly different l evels of tolerance to myrcene, which is explicable in terms of the lik ely concentration of myrcene at the feeding site of each species. Tole rance to monoterpenes maybe specific only to those encountered in high concentrations at the feeding site, whereas others are found to be to xic. This suggests that each species has become physiologically adapte d to tolerate different levels of the specific monoterpenes that occur in the microhabitats they occupy.