Scientists study Anolis lizards

Honolulu -- A U.S. study suggests morphological differences between male and female Anolis lizards of the Greater Antilles are linked with increased biodiversity.

The Anolis lizards of Puerto Rico, Jamaica, Cuba and Hispaniola evolved independently on their respective islands into species that occupy specific niches. But males and females of the same species can be very different -- in some species the sexes are the same size, while in others adult males can be three times larger than females.

Marguerite Butler and colleagues at the University of Hawaii studied five sexually dimorphic characteristics from male and female adults of different niche specialists living on two of the islands. They found sexual dimorphism contributes substantially to biodiversity, helping fuel the bursts of "adaptive radiation" that produced the different niche-adapted species.

Most studies of adaptive radiation ignore sexually dimorphic traits, the researchers noted, but said its place in evolutionary ecology should not be underestimated.

The research appears in the journal Nature.

Copyright 2007 United Press International.