Md. Dearing et S. Cork, Role of detoxification of plant secondary compounds on diet breadth in a mammalian herbivore, Trichosurus vulpecula, J CHEM ECOL, 25(6), 1999, pp. 1205-1219
Theory predicts that mammalian herbivores detoxify different classes of pla
nt secondary compounds via separate metabolic pathways and that generalist
herbivores maintain broad diet breadth to avoid overloading individual deto
xification pathways. We tested the hypothesis that a generalist marsupial h
erbivore, the common brushtail possum, Trichosurus vulpecula. can maintain
a higher intake of food when allowed to select from two diets containing di
fferent profiles of secondary compounds (phenolics and terpenes) than when
given access to the diets individually. Diets consisted of a fruit and vege
table mash to which was added ground leaves of either Eucalyptus melliodora
or E. radiata. E. melliodora and E. radiata differ in their concentrations
and types of secondary compounds. Brushtail possums include these eucalypt
species as parr of their natural diet. We measured food consumption and de
toxification metabolites of possums on these diets. Consistent with the hyp
othesis, animals presented with a choice of both diets consumed more food t
han animals given diets singly. One of the two indicators of detoxification
, acid load in urine, differed significantly between diets while the other,
glucuronic acid, did nor. These results provide partial support for the hy
pothesis that diet breadth is governed by detoxification abilities.