Locomotory behavior of flightless Harmonia axyridis pallas (Col., Coccinellidae)

To improve the efficiency of the ladybeetle Harmonia axyridis as a biologic al control agent against aphids, a flightless population was produced by fe eding adults with a mutagen and selecting their progeny for non-flying but otherwise morphologically normal individuals. The inability to fly could re sult from a change in their flying behavior compared with control adults. F light duration was very much shorter, wing beat frequency and more particul arly the amplitude of the wing beats were clearly lower. More time was spen t on the other components of flight behavior such as wing rotation, wing im mobility and wing folding. The sequence of these patterns differed slightly mainly due to changes in their frequency. The locomotory behavior was not modified by the mutation, which only affected the wing muscles. The searchi ng behavior of mutant adults differed from that of control adults only in t hat they took longer to encounter and ingest aphids. As this difference is not important, it should be possible to use this flightless population in b iological control programs. (C) 2000 Elsevier Science Ltd. All rights reser ved.