EVAPORATIVE WATER-LOSS IN 9 INSULAR POPULATIONS OF THE LIZARD ANOLIS-CRISTATELLUS GROUP IN THE BRITISH-VIRGIN-ISLANDS

We studied water loss in eight insular populations of the lizard Anoli s cristatellus wileyae and in one population of A. ernestwilliamsi in the British Virgin Islands. We found a strong negative correlation bet ween habitat aridity and coral and cutaneous water loss rare (ranging from 1.5-10.3 mg g(-1) h(-1)) and a strong positive correlation betwee n habitat aridity and integument resistance to water loss (28.5-199.0 s cm(-1)). Water loss and integumentary resistance of A. ernestwilliam si were similar to what would be predicted for A. cristatellus living in the same habitat. The Guana Island population of A. cristatellus wa s significantly different from all other populations. We believe two p rocesses are responsible; phenotypic plasticity explains most of the o bserved variability, but genetic differentiation may be responsible fo r the distinction of lizards from Guana.