The Flight Activity and Movements of Myzus persicae (Sulzer) and Brevicoryne brassicae (L.) in a Field Cage

Abstract

Previous work on the behavioural and ecological aspects of aphid migration has not provided a completely satisfactory account of the number and duration of aphid flights (C. G. Johnson 1969; Kring 1972). Myzus persicae Sulz. is an extremely restless aphid, staying on a host long enough to deposit one or two larvae and then moving on (Broadbent & Martini 1959; Kennedy, Booth & Kershaw 1959; van Emden et al. 1969). B. Johnson (1958) suggested that this behaviour might be typical of aphids with wide host ranges since they would frequently land on many plants, on which they could feed, and perhaps deposit a few larvae without being stimulated sufficiently to settle permanently. Kennedy et al. (1959) suggested that 'repeated alighting, brief probing and re-take-off from hosts and non-hosts is a common pattern among migrant Aphididae'. Conversely, other evidence suggests that aphids that have made long migratory first flights would be unlikely to fly again. Although alate Aphisfabae Scop. have been induced to fly again after being flown, tethered on pins, to apparent exhaustion (Cockbain 1961), all the A. fabae tested in other experiments settled permanently on beans, with autolysis of the flight muscles, after tethered flights of 1 h (Cockbain, Gibbs & Heathcote 1963). As Kring (1972) suggests, the flight duration of aphids in the field may be far less than their potential flight duration determined in the laboratory. The close relationship in time between the density of aphids at crop level and the integrated total number of aphids in the air, suggested that flight is rather limited in duration and that most of the aphids caught in traps were making their first flight (C. G. Johnson 1956). This view was supported by the observation that most A. fabae caught in the suction trap at Rothamsted seemed to be young (Taylor 1957). A possible solution to these two conflicting views of the significance of subsequent flights lies in the duration of the first flight. Aphids seen to take off shortly after landing may have been flying only a few minutes (Taylor 1965), but little is known about the extent to which they move after the initial flight in spite of the fact that it is this behaviour that makes alate aphids well suited for spreading viruses in the field (Kennedy 1960). The aim of this paper is to determine the importance of subsequent flights in aphids which had either made long initial flights or been stimulated to settle by long periods of starvation.