title: Insect herbivory on C3and C4grasses.
abstract: This study tested the hypothesis that grasses with the C4photosynthetic pathway are avoided as a food source by insect herbivores in natural communities. Insects were sampled from ten pairs of C3-C4grasses and their distributions analyzed by paired comparisons tests. Results showed no statistically significant differences in herbivore utilization of C3-C4species. However, there was a trend towards heavier utilization of C3species when means for both plant groups were compared. In particular, Homoptera and Diptera showed heavier usage of C3plants. Significant correlations between insect abundances and plant protein levels suggest that herbivores respond to the higher protein content of C3grasses. δ13C values for six of the most common grasshopper species in the study area indicated that three species fed on C3plants, two species fed on C4plants, and one species consumed a mixture of C3and C4tissue.
authors.affiliation: Department of Botany and Range Science, Brigham Young University, 84602, UT, Provo, USA.
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Boutton
authors.affiliation: Program in Population Biology, Department of Biology, University of Houston, 77004, Houston, TX, USA.
authors.forename: Guy N
authors.initials: GN
authors.lastname: Cameron
authors.affiliation: Department of Botany and Range Science, Brigham Young University, 84602, UT, Provo, USA.
authors.forename: Bruce N
authors.initials: BN
authors.lastname: Smith