Fecundity in Captivity of the Green Anoles, Anolis carolinensis, Established on the Ogasawara Islands

The iguanid lizard, green anole Anolis carolinensis, has currently established breeding colonies on several tropical and subtropical Pacific islands. In the Ogasawara Islands, predation by the green anole has collapsed the endemic insect community. Now that the Ogasawara Islands have been inscribed on the World Heritage List as a natural heritage by UNESCO, it is necessary to study the current status and ecological aspects of the green anole there to improve the effectiveness of control efforts. When planning population management for an alien species, information regarding its fecundity (number of eggs laid per female per year) is essential. This species lays only one egg at a time, but lays multiple times during an extensive reproductive season each year. It is therefore difficult to estimate fecundity by ordinary methods, such as gonadal examination by necropsy. In the present study, we maintained 10 female anoles from Chichijima Island in indoor captivity under conditions similar to those of the Ogasawara Islands to record their egg-laying conditions. Egg-laying occurred from April to October with a peak in August, during which each female laid 0.95 eggs/week on an average. The average number of eggs laid by a female in a year was 13.7. Sites selected for laying were spaces between the leaves of ferns and in hollows on the ground. We consider that for efficient control of this species, we should intensively hunt females in April, before their egg-laying frequency begins to increase.