Effects of Varied Electrophoretic Conditions on Detection of Evolutionary Patterns in the Laridae

Abstract

The extent and effects of hidden variation on detecting evolutionary patterns in the family Laridae were examined using sequential starch-gel electrophoresis of proteins. To determine whether more alleles were hidden at higher taxonomic levels than within species, 25 individuals of Sternaforsteri and 20 species in the family Laridae were analyzed. Varied conditions detected two hidden alleles in the 25 S. forsteri, whereas 26 alleles were hidden across the 20 larid species. These alleles were hidden using buffer conditions not commonly employed in avian electrophoretic surveys and had no effect on phylogenetic reconstruction. Distance-Wagner analysis showed the following to be distinct groups: (1) Rynchopinae, (2) Stercorariinae, (3) Anous stolidus, (4) Larinae, and (5) Sterninae. Within the Sterninae, S. antillarum and Chlidonias niger are the most divergent. Sterna maxima and S. forsteri are sister taxa, as are S. nilotica and Phaetusa simplex. Sterna hirundo and S. vittata show no differences at the 23 loci examined, which does not support the hypothesis that S. vittata arose from a migrant population of S. paradisaea that remained in the Antarctic. Cladistic analysis provides evidence that A. stolidus, placed with the Sterninae under all classification schemes, is indeed a tern, but may be evolving faster than other terns. The results of this study agree generally with a morphometric analysis of the Laridae by Schnell (1970a, 1970b).