AMPLIFIED MITOCHONDRIAL DNA AS A DIAGNOSTIC MARKER FOR SPECIES OF CONIFER-FEEDINGCHORISTONEURA(LEPIDOPTERA: TORTRICIDAE)

Abstract

AbstractWe describe a method for identifying conifer-feeding species and lineages ofChoristoneuraLederer in Canada and Alaska. The method relies on amplification of mitochondrial (mt) DNA by the polymerase chain reaction (PCR); amplified DNA is then digested with restriction enzymes to give characteristic DNA fragment patterns. We used the cytochrome oxidase I and II genes of mtDNA, which were previously shown to contain numerous nucleotide differences at the level of species. Ten restriction enzymes were surveyed and a combination of two of these (EcoR V +Hinf I) was sufficient to distinguish the major mtDNA lineages.Choristoneura fumiferana(Clemens),C.pinusFreeman, andC.rosaceana(Harris) were readily distinguished from each other and from an assemblage of three putative western species (C.occidentalisFreeman.C.oraeFreeman, andC.biennisFreeman). The three western species have the same mtDNA marker pattern in most individuals and, although ecologically differentiated, their populations may actually be conspecific. At one locality in Alaska, pheromone traps bailed with lures forC.fumiferanaattract moths withC.fumiferanamtDNA, and lures forC.oraeattract moths with mtDNA that is characteristic of the western assemblage. This demonstrates geographic overlap of genetically distinct species in Alaska. The same two separate mtDNA lineages co-occur at two localities in Alberta, but pheromone attraction is unknown. In British Columbia, populations identified asC.biennisandC.occidentaliscontain a few individuals with divergent mtDNA genotypes, the significance of which remains unclear. Amplified mtDNA thus provides a convenient, reliable marker for surveying genetic variation within species and for studying interactions among species of theC.fumiferanagroup.