Argentine stem weevil Listronotus bonariensis genetic variation in New Zealand and the possible effects on genetic composition of selection pressure by the parasitoid Microctonus hyperodae

Abstract

This contribution describes an ongoing investigation into Argentine stem weevil Listronotus bonariensis genetic variation in New Zealand and possible impacts on genetic composition arising from selection pressure exerted by the parasitoid wasp Microtonus hyperodae. Molecular methodologies initially included comparison of amplified anonymous regions (RAPDs), nuclear, mitochondrial and intron sequences (28S, COI, ITS1, ITS2, CytB) and high resolution melt (HRM) profiles. These approaches showed very limited genetic variation within populations across New Zealand. Most recently a genotyping by sequencing (GBS) approach was used to take advantage of emerging next generation sequencing technology. Very preliminary results using this method showed quite distinct regional differences in weevil DNA with an apparent convergence where high parasitoid selection pressure has been maintained for up to 40 weevil generations. The evolutionary implications of this are discussed in terms of possible weevil resistance to the parasitoid.