Document Type
Article
Journal/Book Title/Conference
American Naturalist
Volume
136
Issue
6
Publisher
University of Chicago Press
Publication Date
1990
Recommended Citation
F. D. Provenza; E. A. Burritt; T. P. Clausen; J. P. Bryant; P. B. Reichardt; R. A. Distel. The American Naturalist, Vol. 136, No.6 (Dec., 1990), 810-828.
First Page
810
Last Page
828
Abstract
It has been hypothesized that herbivores instinctively avoid tannin-containing plant parts in response to the adverse effects of tannins on forage digestion. However, we found that goats learned to avoid condensed tannins (CTs) from blackbrush current season's growth by associating the flavor of foods containing CTs with aversive postingestive consequences. The aversive consequences experienced by goats apparently are not related to digestion inhibition and may depend on the structure of CTs and on how CTs are bound with other cell constituents. These observations suggest several areas of inquiry related to the interaction between CTs and herbivores. A better understanding of the physiological effects of CTs and how herbivores perceive these effects is essential to our knowledge of chemically mediated interactions between plants and mammalian herbivores. With few exceptions, the effects of food flavor have not been separated from those associated with postingestive consequences, even though our data show that postingestive consequences strongly influence palatability. We also need to know how herbivores learn which plant species to eat and which to avoid while foraging in areas that contain a variety of plant species and parts with different kinds and concentrations of CTs. Condensed tannins are pervasive in nature and can defend plants from herbivory, but since many important forages contain high levels of tannins, the presence or absence of tannins per se does not reliably indicate food quality. To predict the ability of a tannin-producing plant to deter herbivores requires a full understanding of how changes in CT structure and binding affect herbivores.
Comments
Originally published by the University of Chicago Press on behalf of the American Society of Naturalists. Publisher's PDF available online through the American Naturalist.