Flight Activity of Rhyzopertha dominica (Coleoptera: Bostrichidae) in Response to Feeding Damage and Accumulation of Waste

Abstract

The effects of insect-damaged wheat ( Triticum aestivum L.) kernels, frass, and uric acid on flight initiation by the lesser grain borer, Rhyzopertha dominica (F.), reared in crowded and uncrowded cultures were determined. In all 3 treatments, beetles reared in uncrowded cultures had a significantly lower flight initiation rate than beetles reared in crowded cultures. Beetles reared in crowded cultures and exposed to insect-damaged wheat kernels had a significantly higher flight initiation rate than beetles exposed to whole or mechanically damaged wheat kernels. Although beetles in uncrowded cultures had a low flight response, the number of beetles initiating flight increased with exposure to increased concentrations of frass or uric acid. These results indicate that the high flight initiation rate of R. dominica reared in crowded cultures can be explained partially by greater insect-feeding damage and accumulation of waste in crowded compared with uncrowded cultures.