SENSORY STIMULI INVOLVED IN THE LOCATION AND SELECTION OF SAWFLY COCOONS BY SMALL MAMMALS

Abstract

The stimuli responsible for the location and selection of healthy vs. parasitized and diseased sawfly prepupae by Peromyscus maniculalus bairdii Hoy and Kenicott, Sorex cinereus cinereus Kerr, and Blarina brevicauda talpoides Gapper were determined in all phases of the search for buried food. Only olfactory stimuli were involved in the digging, removing, and opening phases, while gustatory stimuli played a part in selection in the eating phase. There were innate preferences and a versions to the gustatory stimuli, but not to the olfactory stimuli. It was only with experience that the animals were able to associate odors from cocoons with the taste of the cocoon contents.The selection of healthy male vs. female cocooned prepupae was also studied. In the digging phase all species dug more holes over the larger female cocoons than over the smaller male cocoons. This selection was not affected by experience and was caused by differences in degree and not kind of odor. In the removing and opening phases S. c. cinereus and P. m. bairdii removed and opened more male than female cocoons, while B. b. talpoides removed and opened more female cocoons. This selection was affected by experience and probably resulted from differences in visual or tactile stimuli. The larger the mammal the greater was the selection for female cocoons.