Reproductive adaptations of the green iguana on a semiarid island
Copeia
1993
Journal Article
790-798
Iguana iguana
Reproductive cycle and clutch size were studied in the green iguana (Iguana iguana) on the semiarid Caribbean island of Curaçao. The reproductive cycle is correlated with seasonality in rainfall. Mating is in the first half of the dry season, egg laying in the second part of the dry season, and hatchling emergence approximately two months before the onset of the rainy season. On Curaçao, many plants produce young leaves after the first rains in summer well before the heavy rains start. Emergence appears timed to ensure that hatchlings can take advantage of a long growing period before entering the dry season, and takes place when lush foliage is available to the young iguanas. Number of eggs, clutch mass, and individual egg mass are positively related to female body mass. Relative clutch mass (RCM = 0.32) appears independent of body mass. Adult female iguanas from Curaçao are much smaller (maximal snout-vent length is 31 cm) than iguanas from Panama and other humid mainland habitats. Relative clutch mass is similar to that of mainland animals, but Curaçao iguanas produce significantly fewer, but larger, eggs that give rise to larger hatchlings. These differences probably reflect adaptations to the semiarid environment on Curaçao.