Utilization of evergreen and decidous oaks by the Californian oak moth Phryganidia californica

Abstract

The deciduous oak Quercus lobata was a better quality food source than the evergreen oak Q. agrifolia for the California oak moth Phryganidia californica: it supported higher growth rates, produced higher fecundity and survivorship, and higher efficiency of conversion of ingested food (ECI), efficiency of conversion of digested food (ECD) and efficiency of nitrogen utilization (NUE). Total polyphenols and astringency were similar in both oak speices, whereas water content was lower and leaf specific weight higher in Q agrifolia than in Q lobata. Nitrogen was higher in new leaves of Q agrifolia but higher in mature leaves of Q. lobata. Contrary to most other studies, total polyphenols and astringency were higher in new than in mature leaves. These results confirmed my hypothesis that the differences in leaf quality associated with the evergreen or deciduous life form would translate into food of differing quality for herbivores.