Variation in behavioural migration in aphids

The behaviour of Aphis fabae during maiden flight in an automated flight chamber was assessed by their response to the intermittent presentation of a plant-like visual target. As shown previously, alate virginoparae were much more responsive to the target, i.e. indicating foraging flight, during the initial part of maiden flight than were gynoparae. Virginoparae initiated foraging flight after a short behavioural migratory period, i.e. the initial period of flight when the aphid remains unresponsive to the target, (on average 8 ± 5 min) while gynoparae undertook a longer migratory flight (on average 102 ± 19 min). However, if starved for 24 h, under conditions that did not allow flight, both aphid forms initiated foraging flights more readily and the period of behavioural migration was reduced (0.7 ± 0.3 vs 36 ± 11 min, virginoparae vs gynoparae). This observation indicates that the initiation of foraging flight, and thus the duration of migratory flight, can be influenced by factors other than flight per se.