Detection of Rhopalosiphum insertum (apple-grass aphid) predation by the predatory mite Anystis baccarum using molecular gut analysis

1 A simple, yet sensitive polymerase chain reaction based technique was developed for the detection of the apple-grass aphid Rhopalosiphum insertum in the gut of Anystis baccarum, a predatory mite. 2 A range of conserved polymerase chain reaction primers for insect mitochondrial and ribosomal DNA were tested in order to amplify R. insertum DNA. The mitochondrial DNA primers LrRNAR2+N1F1, amplified a region between the ND1 and large subunit RNA genes. 3 DNA sequencing of the R. insertum ND1-LRNA polymerase chain reaction product allowed aphid-specific polymerase chain reaction primers to be designed. These amplified a 283-bp product from individual aphids. No polymerase chain reaction product was amplified from individual A. baccarum. 4 Using the aphid-specific primers against A. baccarum fed on R. insertum, the diagnostic 283-bp product was amplified. 5 Two restriction enzymes (RsaI and AluI) produced patterns that allowed unambiguous identification of R. insertum DNA from that of Macrosiphum euphorbiae and Myzus persicae.