Prey feeding increases water stress in the omnivorous predator Dicyphus hesperus

The effects of water stress (produced by water deprivation and prey feeding) on plant feeding were investigated in the omnivorous predator Dicyphus hesperus Knight (Hemiptera: Miridae). The objective was to determine if prey feeding aggravated water deficits and thus increased plant feeding. We measured plant feeding in a factorial experiment where female D. hesperus were prepared for experiments by providing or withholding water and/or prey for 24 h. We then evaluated the amount of plant feeding on Nicotiana tabacum seedlings by the direct observation of insects at three different densities of the prey, Ephestia kuehniella eggs. The amount of plant feeding, as measured by frequency of plant feeding bouts and time spent plant feeding during observation, was significantly greater for water-deprived individuals than for those that had been provided with water. Individuals that had been provided with prey fed on plants at a significantly higher frequency than prey-deprived individuals at two of the prey densities used in the experiment. These results support the hypothesis that plant feeding in zoophytophagous Hemiptera facilitates prey feeding by providing water that is essential for predation. [ABSTRACT FROM AUTHOR]