Behavioral and molecular mechanisms associated with the differential susceptibility of selected clonal lines of Myzus persicae (Sulz.)(Hemiptera: Aphididae) to parasitization by Aphelinus asychis (Walker)(Hymenoptera: Aphelinidae)

Abstract

During their evolution insects acquired a number of defensive strategies as their co-evolved with their natural enemies, which included morphological, behavioral and/or physiological adaptations. Moreover, insects also gained new features by associating with microbial symbionts. Many studies focused on the understanding of the immune response pathways of insects to natural enemies, but few have attempt to investigate the molecular basis of the immune response involved in host resistance to parasitism. In our previous studies, we identified intra and interpopulational differences in the parasitism rates of clonal lines of two populations of Myzus persicae. The selection of lines with different susceptibility to parasitization by Aphelinus asychis for comparative biology studies revealed the existence of adaptive costs associated with lines that are less susceptible to parasitism. The verification of the association with symbionts did not indicate the existence of defensive symbionts, with the exception of Spiroplasma, which infected all clonal lines investigated, showing this symbiont did not have a defensive role in this aphid - parasitoid association. The aim of this project is to identify the molecular and/or behavioral mechanisms involved in the lower susceptibility of clonal lines of the aphid to parasitism by A. asychis, through comparisons of differential gene expression and host/parasitoid behavioral patterns which would explain the differences found among the selected clonal lines of M. persicae.