Intra-specific variation of behavioral signals in suppressing plant defenses in the green peach aphid Myzus persicae, feeding on the resistant wild peach Prunus davidiana

The green peach aphid, Myzus persicae (Sulzer), is a generalist insect herbivore capable of using a wide range of cultivated plants and weeds. In this laboratory study, we examined the inter-clonal variation in M. persicae’s ability to exploit the wild peach Prunus davidiana, a source of genetic resistance to aphids used by peach breeding programs. An initial screening of a set of sexually reproducing clones collected from commercial orchards planted with susceptible varieties found significant genetic variation in aphid survival on P. davidiana. Comparison of two clones (Fr2 and Fr12) found marked differences in colony sizes achieved. A detailed analysis of probing and feeding behavior showed that the clone exhibiting the highest performance on P. davidiana (Fr2) initiated probing earlier than the lower performing clone (Fr12). Periods of non-probing were also significantly shorter for this clone. Finally, Fr2 produced more and longer events of watery saliva injection into sieve elements. We discuss these results in terms of host plant adaptation by aphids and their capacity to overcome plant-resistance genes.