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 distribution across individuals of its host plant, the Mexican cypress, Cupressus lusitanica (Mill).

2. There are significant differences in host plant quality: C.cupressi nymphs transplanted onto cypress trees with low aphid infestations are significantly less likely to establish than aphids transplanted onto trees with high aphid infestations.

3. Given that some transplanted nymphs establish, the previous level of infestation does not influence aphid survival.

4. Evidence for local adaptation 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 trees with similar levels of infestation. Therefore the variation in host plant quality has not led to the development of local adaptation to particular host plants.