Phylogenetic utility of elongation factor-1 alpha in noctuoidea (Insecta: Lepidoptera): the limits of synonymous substitution

To test its phylogenetic utility, nucleotide sequence variation in a1,240-bp fragment of the elongation factor-1 alpha (EF-1 alpha) gene wasexamined in 49 moth species representing the major groups of thesuperfamily Noctuoidea. Both parsimony and distance analyses supported themonophyly of nearly all groups for which there are clear morphologicalsynapomorphies. Clades of subfamily rank and lower, probably mid-Tertiaryand younger, were strongly supported. The third codon position contains 88%of variable sites, and approaches saturation at approximately 20% sequencedivergence, possibly due to among-site rate heterogeneity and compositionbias; higher divergences occur only in association with shifts incomposition. Surprisingly, the few nonsynonymous changes appear no morephylogenetically reliable than synonymous changes. Signal strength forbasal divergences is weak and fails to improve with character weighting;thus, dense taxon sampling is probably needed for strong inference fromEF-1 alpha regarding deeper splits in Noctuoidea (probably early Tertiary).EF-1 alpha synonymous changes show promise for phylogeny reconstructionwithin Noctuidae and other groups of Tertiary age.