INTRASPECIFIC VARIATION IN HOST-PLANT QUALITY - THE APHID CINARA-CUPRESSI ON THE MEXICAN CYPRESS, CUPRESSUS-LUSITANICA

1. In Kenya, the aphid Cinara cupressi (Buckton) has an aggregated dis tribution across individuals of its host plant, the Mexican cypress, C upressus lusitanica (Mill). 2. There are significant differences in ho st plant quality: C.cupressi nymphs transplanted onto cypress trees wi th low aphid infestations are significantly less likely to establish t han aphids transplanted onto trees with high aphid infestations. 3. Gi ven that some transplanted nymphs establish, the previous level of inf estation does not influence aphid survival. 4. Evidence for local adap tation to individual plants was not found: nymphs transplanted to the trees from which their parents were collected neither established more readily nor showed lower mortality than those transplanted to other t rees with similar levels of infestation. Therefore the variation in ho st plant quality has not led to the development of local adaptation to particular host plants.