The influence of predators on the movement of apterous pea aphids between plants

TLDR: Evidence is presented which suggests fecundity is reduced the day after an aphid disperses, and the significance of dispersal by apterous aphids is discussed in the light of evidence presented.

Abstract: SUMMARY (1) This paper examines the influence of predators on the dispersal of apterous pea aphids in the laboratory and field. (2) Individual pea aphids can be placed in one of two categories, searchers and runners, depending upon the behaviour they exhibit after dropping from their host plant. (3) In field cages, pea aphids readily disperse to new host plants in the presence of predators. Dispersal of apterous aphids is rare when active predators are absent. (4) Evidence is presented which suggests fecundity is reduced the day after an aphid disperses. (5) The distance dispersed by aphid nymphs is positively correlated with the density of aphids on the plant the aphid leaves. (6) The significance of dispersal by apterous aphids is discussed in the light of evidence presented.