Effect of Host-plant Genotype and Neighboring Plants on Strawberry Aphid Movement in the Greenhouse and Field

Abstract

Abstract Herbivore movement behavior is a key mediator of how host-plant populations affect herbivore populations. We examined the effects of host-plant genotype and variance among host-plant genotypes on movement rates of apterous strawberry aphids, Chaetosiphon fragaefolii (Cockerell) (Homoptera: Aphididae), on Fragaria chiloensis (L.) P. Mill. In the field we estimated aphid movement rates over several years on experimental populations of five different plant genotypes. In the greenhouse, we followed the movement of individual aphids in plant arrays of a single genotype or three different genotypes. In both cases, aphid apterae movement differed among host plant genotypes, with more movement on higher quality genotypes. Movement rate in the field was also influenced by aphid population size. In the greenhouse, aphids showed no taxis toward particular plant genotypes but left different plant genotypes at different rates. Aphids also tended to move more often among plants in three genotype arrays (with a...