Published online by Cambridge University Press: 10 July 2009
The mid-winter development, reproduction and survival of field-acclimatized viviparae of Sitobion avenae (F.) and Rhopalosiphum padi (L.) on leaves of tillering wheat and perennial ryegrass (Lolium perenne) plants at similar growth stages were compared by monitoring batches of aphids in clip-cages in field plots in southern England. For both aphid species, survival, total fecundity and reproductive rate were much higher on wheat than on L. perenne, and on both host-plants they were much higher for S. avenae than for R. padi. Development times (in day-degrees) were longer on L. perenne than on wheat, and on both host-plants were longer for R. padi than for S. avenae, though these differences were less marked. Comparison of the results with those of earlier studies suggests that large changes in cereal aphid performance occur between summer and winter and that these are both aphid-specific and host-plant-specific.