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 a 1 ,240-bp fragment of the elongation factor-1 alpha (EF-1 alpha) gene wa s examined in 49 moth species representing the major groups of the sup erfamily Noctuoidea. Both parsimony and distance analyses supported th e monophyly of nearly all groups for which there are clear morphologic al synapomorphies. Clades of subfamily rank and lower, probably mid-Te rtiary and younger, were strongly supported. The third codon position contains 88% of variable sites, and approaches saturation at similar t o 20% sequence divergence, possibly due to among-site rate heterogenei ty and composition bias; higher divergences occur only in association with shifts in composition. Surprisingly, the few nonsynonymous change s appear no more phylogenetically reliable than synonymous changes. Si gnal strength for basal divergences is weak and fails to improve with character weighting; thus, dense taxon sampling is probably needed for strong inference from EF-1 alpha regarding deeper splits in Noctuoide a (probably early Tertiary). EF-1 alpha synonymous changes show promis e for phylogeny reconstruction within Noctuidae and other groups of Te rtiary age.