Plant water deficits and insect responses: the preference of Corythucha arcuata (Heteroptera: Tingidae) for the foliage of white oak, Quercus alba

, ABSTRACT. 1. The preference of Corythucha arcuata (Say) (Heteroptera: Tingidae) for the foliage of Quercus alba L. (Fagaceae) grown under water deficit was examined. Potted Q.alba saplings were grown under controlled levels of water deficit in a glasshouse. Adult C. arcuata were exposed to excised Q.alba foliage under controlled conditions in a growth chamber, and feeding preference assessed by recording the percentage of individuals feeding on leaves from each level of water deficit. 2. Two experiments were performed. In the first, all foliage was supplemented with water (via the petiole) to alleviate physical changes in the leaves that accompany plant water deficits. In the second experiment, leaves were not supplemented with water. 3. C.arcuata had no preference when presented water supplemented leaves, but preferred leaves that were fully hydrated when presented leaves that were not supplemented with water. 4. These results suggest that plant water deficits are important in determining the feeding preference of C.arcuata because they lead to avoidance of drought grown foliage. This avoidance may be caused by an increase in the metabolic cost to the herbivore of maintaining water balance when ingesting drought grown foliage or to an increase in foliage toughness.