Isoelectric focusing electrophoresis and RFLP analysis: Two methods for immature Orius spp. identification

Two techniques were used to discriminate between second instar Orius minutu s (L) and Orius sauteri (Poppius) which occur sympatrically in eggplant fie lds of Japan. Isoelectric focusing (IEF) was used to discriminate between t he two species utilizing the enzyme isocitrate dehydrogenase (IDH). Moreove r, IEF was also shown to detect the presence of the prey Thrips palmi Karny in O. sauteri nymphs immediately after feeding by using phosphogluco-isome rase (PGI). PCR generated internal transcribed spacer 1 (ITS-1) regions for nymphs of both species were also diagnostic as the O. minutus PCR product was much larger than the O. sauteri PCR product (900 vs. 600 bp). Moreover, by comparing ITS-1 PCR product sizes and using the restriction enzyme Hinf I on ITS-I products of similar size to produce restriction fragment length polymorphisms (RFLPs), consistent differences among five Japanese Orius spe cies were also demonstrated.