DIET OF SOREX-CINEREUS, THE MASKED SHREW, IN RELATION TO THE ABUNDANCE OF LEPIDOPTERA LARVAE IN NORTHERN ONTARIO

We examined the diet of Sorex cinereus (masked shrew) and abundance of Lepidoptera larvae over 3 yr. Shrews and Lepidoptera larvae were samp led in a 40-yr-old jack pine (Pinus banksiana) plantation near Gogama, Ontario, Canada. Shrews consumed a high-er proportion of Lepidoptera larvae when Lepidoptera larvae were more abundant on low shrubs, herbs , and ground level. Sorex cinereus showed a functional response to cha nges in the abundance of Lepidoptera larvae. These larvae were the pri mary food of shrews, and juveniles consumed higher proportions than ad ults. This may explain the high abundance, large litter size and juven ile recruitment of shrews reported previously for the same plantation during 1985.