Complexity in Dioryctria zimmermani species group: Incongruence between species limits and molecular diversity

Dioryctria (Zeller 1846) (Lepidoptera: Pyralidae: Phycitinae) moths, commonly known as coneworms, are a group of important coniferous pests. Interspecific overlap of molecular, morphological, and behavioral traits has made identification and delimitation of these species problematic, impeding their management and control. In particular, delimitation of members of the Dioryctria zimmermani species group, a diverse group of Nearctic species, is notoriously difficult. To clarify the species boundaries in this species group we examined two independent molecular markers (cytochrome c oxidase I and II and elongation factor 1α), larval host plant association, geographic distribution, and pheromone attraction in an integrated taxonomic framework. Congruence between these diagnostic traits and established species limits in the zimmermani group was variable. Some species showed well-supported congruence between established taxonomic limits and mitochondrial DNA gene tree topology, whereas other species showed little phylogenetic resolution, little correspondence with diagnostic traits, and incongruence with previously described species limits. Gene tree-species tree discordance may be caused by several evolutionary processes, such as imperfect taxonomy, incomplete lineage sorting, or introgression. Additional information, such as highly variable molecular markers, morphometrics, and larval host information, is needed to effectively evaluate and differentiate among these alternative hypotheses and fully resolve the species limits among D. zimmermani species group members.