Effects of Weevil Larvae on Acorn Use by Blue Jays

Document Type

Article

Publication Date

7-1997

Keywords

Blue Jay, Tri-trophic interactions; Oaks; Tannins; Weevils

Abstract

Blue jays (Cyanocitta cristata L.) are important consumers and dispersers of the nuts of oaks and other fagaceous trees in eastern North America. Acorns compose much of the jay diet, especially during the autumn when jays may consume or cache a significant portion of an acorn crop. However, jays do not appear to possess physiological adaptations for countering the protein-binding properties of secondary compounds (tannins) found in acorns. We offered captive blue jays a mixture of infested and uninfested pin oak (Quercus palustris Muenchh.) acorns to see if the birds would selectively consume nuts containing weevil larvae (Coleoptera: Curculionidae) as a protein supplement to a high-tannin, all-acorn diet. Acorns were X-rayed to determine infestation status and then offered to individual jays in an outdoor aviary. Jays handled, opened, and consumed uninfested nuts significantly more often than infested nuts, and use of infested nuts did not increase during continued exposure to a high-tannin diet.

Publication Title

Oecologia

Volume

111

Issue

2

First Page

201

Last Page

208

Pages

8

DOI of Published Version

10.1007/s004420050226

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