A Comparative Display Analysis of the Anolis brevirostris Complex in Haiti

The stereotyped head bob displays of three Anolis sibling species, formerly recog- nized only as A. brevirostris, were quantitatively analyzed from 736 filmed displays by 46 subjects. The three species are sequentially distributed along the west coast of Haiti, with A. websteri in the north, A. caudalis in the middle, and A. brevirostris in the south. It has been hypothesized that a behavioral isolating mechanism, such as the head bob displays, was serving to separate the species. Our data support this possibility. Each species' behavioral repertoire contained two categories of homologous and species-unique displays: the Type A and B displays. A single Type A display pattern was found in each repertoire, and it served as the species' signature display. The Type B displays were more complex than the A displays, and in A. brevirostris and A. websteri were represented by two and three different vari- ations, respectively. Each species' A display resembled that of its siblings; however, discriminant analysis procedure clearly discriminated between the three A display patterns. Likewise, the B display patterns of the combined sibling repertoires were also clearly separated by the discriminant analysis procedure, confirming their species uniqueness. Interspecific comparisons showed the larg- est differences in homologous displays to occur among geographically adjacent species, especially between the displays of A. websteri and A. caudalis. Character displacement may have enhanced these differences.