Flight activity of Rhyzopertha dominica (Coleoptera : Bostrichidae) in response to feeding damage and accumulation of waste

The effects of insect-damaged wheat (Triticum aestivum, L.) kernels, frass, and uric acid on night initiation by the lesser grain borer, Rhyzopertha d ominica (F.),reared in crowded and uncrowded cultures were determined. In a ll 3 treatments, beetles reared in uncrowded cultures had a significantly l ower flight initiation rate than beetles reared in crowded cultures. Beetle s reared in crowded cultures and exposed to insect-damaged wheat kernels ha d a significantly higher night initiation rate than beetles exposed to whol e or mechanically damaged wheat kernels. Although beetles in uncrowded cult ures had a low night response, the number of beetles initiating night incre ased with exposure to increased concentrations of frass or uric acid. These results indicate that the high night initiation rate of R. dominica reared in crowded cultures can be explained partially by greater insect-feeding d amage and accumulation of waste in crowded compared with uncrowded cultures .