@article {JRN53927, title = {Is differential use of Juniperus monosperma by small ruminants driven by terpenoid concentration}, journal = {Journal of Chemical Ecology}, volume = {40}, year = {2014}, month = {02/2014}, pages = {285-293}, chapter = {285}, abstract = {

We examined the relationship between volatile plant secondary metabolite concentrations and Juniperus monosperma herbivory by small ruminants. Two groups of animals (10 goats or 5 goats plus 4 sheep) browsed 16 paddocks (20 x 30 m) containing one-seed juniper for six days during two seasons. Juniper leaves were sampled from 311 saplings on the same day they were browsed. Saplings were categorized by size (short [\< 0.5 m], medium [0.5-1.0 m] or tall [\> 1.0 m]) and browsing intensity (light [\< 33\%], moderate [33-66\%] or heavy [\> 66\%]). Juniper bark was also collected from 12 saplings during spring. Total estimated terpenoid concentrations in leaves and bark were 18.3 \± 0.3 and 8.9 \± 0.8 mg/g, respectively, and the dominant terpene in both tissues was a-pinene (11.1 \± 0.2 and 7.6 \± 0.7 mg/g, respectively). Total terpenoid concentration was greater (P \< 0.001) in spring than summer (20.6 \± 0.5 vs. 16.7 \± 0.3 mg/g, respectively) and lower (P \< 0.001) in short saplings than medium or tall saplings (16.5 \± 0.6 vs. 19.8 \± 0.4 and 19.5 \± 0.4 mg/g, respectively). Total concentration also differed (P \< 0.001) among the three defoliation categories (16.1 \± 0.4, 18.7 \± 0.5, and 21.2 \± 0.6 mg/g for heavy, moderate, and light, respectively). The smallest subset of terpenes able to discriminate (P \< 0.001) between heavy and light browsing intensity categories included eight compounds ([E]-\ß-farnesene, bornyl acetate, \&$\#$39;-eudesmol, endo-fenchyl acetate, y-cadinene, a-pinene, cis-piperitol, and cis-p-menth-2-en-1-ol).

}, keywords = {goats, herbivory, one-seed juniper, Oxygenated terpenes, Resource availability hypothesis, sheep, targeted grazing, terpenes}, doi = {10.1007/s10886-014-0389-1}, url = {/files/bibliography/14-006.pdf}, author = {Richard E. Estell and S. A. Utsumi and Andr{\'e}s F. Cibils and D.M. Anderson} }