Biennial Reproduction with a Fourteen-Month Pregnancy in the Gecko Hoplodactylus maculatus from Southern New Zealand

Abstract

Hoplodactylus maculatus is a small, nocturnal and viviparous gecko that is widespread throughout New Zealand and represents a complex of several undescribed species. Common geckos in the Macraes-Middlemarch region of Central Otago in southern New Zealand have a biennial ovarian cycle with virtually continuous ovarian activity. Females begin vitellogenesis in autumn and ovulate the fol- lowing spring. Pregnant females carry full-term, viable embryos by the end of autumn about 7 mo after ovulation, but remain pregnant during the subsequent winter. Parturition occurs the following late spring or summer, about 14 mo after ovulation. In populations of this species complex in three other regions of New Zealand, annual ovarian cycles with a 3-5 mo pregnancy have been reported. Biennial reproduction in the Macraes-Middlemarch region is associated with colder temperatures during spring-autumn than in regions with annual reproduction. Common geckos from the Macraes-Middlemarch region also have larger body sizes and a smaller mean litter size than in two populations with annual reproductive cycles. Small litter size and biennial reproduction in the Macraes-Middlemarch region result in an annual reproductive output of about 0.85 young, comparable with the lowest value reported for any other lizard. These findings imply a long life-span in common geckos from this region.