1996/05/17 by M. A. Steele, Michael A. Steele, L. Z. Hadj-Chikh +1 · 4 citations
Environmental Science · Agricultural and Biological Sciences · #Animal Ecology and Behavior Studies #Plant and animal studies #Insect and Pesticide Research
paper · pdf · doi:10.2307/1382802
We tested the caching and feeding responses of gray squirrels (Sciurus carolinensis) to acorns of three species of oaks (Quercus alba, Q. palustris, and Q. rubra) infested with weevil larvae (Curculio). Experiments were designed to test the primary hypothesis that squirrels selectively cache sound acorns and the secondary hypothesis that such response may be due to increased perishability resulting from infestation. In an open, suburban oak (Quercus) forest in northeastern Pennsylvania, we presented free-ranging animals with whole, infested acorns, whole, noninfested acorns, and noninfested acorns from which the pericarp (shell) was removed to increase perishability. Squirrels cached significantly (20–35%) more of whole, intact acorns of red oak, dispersed these acorns significantly greater distances before caching them, and consumed shelled and infested acorns. Squirrels showed a similar response to acorns of pin oak, but ate significantly more of both infested and noninfested acorns of white oak. Squirrels also were observed to consume weevil larvae in >76% of all trials with infested acorns. These results indicate that squirrels can distinguish between infested and noninfested acorns, that they often selectively cache sound acorns, and that weevils represent a significant dietary supplement for squirrels. We also suggest that gray squirrels may exert a strong influence on the dispersal of oaks by selecting viable seeds for storage.