Species Recognition, Dewlap Function and Faunal Size

Abstract

synopsis. Although having a number of functions in reproductive, territorial and aggres? sive behavior, Anolis dewlaps are only one means of intraspecific signaling and they are always present in small anole faunas (e.g., those of one or two species islands) but here, in contrast to the situation in large faunas, their color and pattern appear usually very similar and appear to be unimportant for species (or population) recognition. The latter function is then performed by such characteristics as adult size and body color and pattern. Where, however, numerous species abut or overlap, dewlap color and pattern tend to be diverse and diagnostic (particularly between overlapping forms). Even here, however, adult size, body shape and body color often redundandy reinforce the species and population recognition function of even marked dewlap difference. In certain cases in complex faunas, size and/or body pattern substitute for the species recognition function of reduced or absent dewlaps. In Rand and Williams (1970) we argued that species recognition in anoline lizards is not based on a single sign stimulus or releaser but on a complex of stimuli, re? dundant to each other, which separately and in various combinations identify the display animal. Because natural selection insists that mates be recognizable under a variety of conditions, we have argued that selection must favor a system in which species identity is encoded redundantly. In the specific case analyzed by us in 1970?species recognition in the eight species sympatric at a single locality, La Palma, on the Greater Antillean island of Hispaniola?we found that each of the eight species differed from the rest in several (average 2-*/2) characteristics ofthe dewlap. Thus the dewlap alone sufHced to