The relationship between foliar nitrogen content and feeding by Odontota dorsalis Thun. on Robinia pseudoacacia L.

The relationship between total foliar nitrogen content and feeding by Odontota dorsalis Thun. on Black Locust trees (Robinia pseudoacacia L.) was examined via experimental manipulation of foliar nitrogen levels. Trees with high concentrations of foliar nitrogen received more herbivory by adult O. dorsalis, but herbivory by larvae was independent of foliar nitrogen concentration. Late in the growing season, leaf abscission induced by herbivory tends to mask the dependence of herbivory by adults on foliar nitrogen concentration. The percentage of variation in herbivory attributable to foliar nitrogen concentration drops from 20% in June to 2% by August. These observations suggest that variation in the interaction between R. pseudoacacia and O. dorsalis is at least partially conditioned on variation in foliar nitrogen concentration.