Pea aphid (Homoptera : Aphididae) fecundity, rate of increase, and within-plant distribution unaffected by plant morphology

Plant morphology has been shown to influence the biology of herbivores thro ugh changes in oviposition behavior, feeding preferences, and plant tenure times. The goal of the work herein was to establish whether or not differen ces in plant morphology can affect the performance and distribution of the pea aphid. Acyrthosiphon pisum (Harris), on peas, Pisum sativum L. Fecundit y and intrinsic rate of increase were the selected parameters to measure th e aphid's performance. Genetic near-isolines of the garden pea were used to determine the effect of plant morphology on the pea aphid. The use of gene tic near-isolines eliminates as much as possible confounding effects, such as phytochemicals, that could occur when comparing different plant species or cultivars. Four plant lines differing in leaf morphology (Normal, af; tl , and aftl) and two lines with normal and reduced stipules (Normal and st) were tested. Changes in plant morphology did not have a significant effect on pea aphid total fecundity or intrinsic rate of increase. Although there were no changes in fecundity caused by plant morphology, longevity was sign ificantly influenced both by leaf type and stipule size. The morphology of the leaf did not affect the within-plant distribution of the pea aphid on t hree plant lines tested.