Factors influencing initiation of flight by Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae)

Abstract

Rhyzopertha dominica is the most important pest of stored grain in Australia, in part because of its well known, but poorly documented, ability to fly long distances and find new parcels of grain. In this paper we consider the influences of population density, starvation, age and time of day on initiation of flight of adult R. dominica. Effect of population density was investigated by collecting the progeny from cultures initiated with eggs from 7 days' oviposition by 8, 32, 125 or 500 adults in 125 ml flour. Higher population densities led to a higher proportion of the progeny flying from the cultures, at least for a period after the start of progeny emergence. The flight activity of adults of different ages that had been starved for different periods was studied at different times of day, and flight activity was most intense just before dark. Recently emerged adults were most responsive to influences stimulating flight, either density or starvation, which is typical of migratory insects.