MITOCHONDRIAL-DNA SEQUENCE VARIATION AMONG PHEROMOTYPES OF THE DINGY CUTWORM, FELTIA-JACULIFERA (GN) (LEPIDOPTERA, NOCTUIDAE)

The dingy cutworm, Feltia jaculifera, is a complex of at least four ph eromonal races (pheromotypes). We examined mitochondrial DNA (mtDNA) s equence and restriction-site variation in the cytochrome oxidase subun it I and II genes. Among 74 specimens representing the four pheromotyp es, we found three discrete mitochondrial lineages. The most divergent mtDNA within F. jaculifera, the gamma lineage, was associated with ph eromotype C. This result confirms an earlier allozyme survey, which al so found that pheromotype C was the most genetically distinct race. Th us, pheromotype C probably represents a classic sibling species. Of th e two most similar mitochondrial lineages, the alpha lineage was dispr oportionately associated with pheromotype A and the beta lineage was d isproportionately associated with pheromotypes B and D. Although the c orrespondence between mitochondrial lineages and pheromotypes was inco mplete, mtDNA variation provides strong nonbehavioral evidence for gen etic divergence between pheromotypes A and B + D. Allozymes revealed m ore minor differentiation among the A, B, and D races. For pheromotype s A and B, the presence of distinct mtDNA lineages within populations without perfect correspondence to pheromone polymorphism has several p ossible explanations. It may be due to retained ancestral mtDNA polymo rphism, whether initial divergence of pheromone races occurred in allo patry or sympatry, or to divergence in isolation with introgression fo llowing secondary contact. The greater differences in allele frequenci es of mtDNA than of allozymes may be due either to the susceptibility of mtDNA to bottleneck effects or to asymmetric selection against hybr id females.