Herbivore avoidance of digitalis extracts is not mediated by cardiac glycosides.
This study was conducted to determine whether avoidance of digitalis (Digitalis purpurea) by mountain beaver (Aplodontia rufa) is induced by toxic cardiac glycosides. High-performance liquid chromatography and behavioral assays were used to relate animal responses with the presence of common cardiac glycosides in several digitalis extracts. Statistical analyses of multiple-choice tests showed no correlation between cardiac glycoside content and mountain beaver avoidance of apple cubes treated with digitalis extracts. Therefore, we concluded that known toxic cardiac glycosides were not responsible for chemosensory cues that inhibited intake of food treated with digitalis extracts. These results suggest that digitalis is a source of an effective nontoxic herbivore repellent.
United States Department of Argiculture Animal and Plant Health Inspection Service, Denver Wildlife Research Center, 9701 Blombreg Street, 98512, Olympia, Washington.
D L
DL
Nolte
K L
KL
Kelly
B A
BA
Kimball
J J
JJ
Johnston