Equal thermal opportunity does not result in equal gestation length in a cool-climate skink and gecko

Published source details Cree A. & Hare K.M. (2010) Equal thermal opportunity does not result in equal gestation length in a cool-climate skink and gecko. Herpetological Conservation and Biology, 5, 271-282.
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This study is summarised as evidence for the following.

	Action	Category
	Maintain wild-caught, gravid females in captivity during gestation Action Link
	Use hormones and/or other drugs during captive-breeding programmes to induce reproduction/birth Action Link

Maintain wild-caught, gravid females in captivity during gestation

A study in 2005–2008 in rocky grassland and laboratory conditions in South Island, New Zealand (Cree & Hare 2010) found that most wild pregnant McCann’s skinks Oligosoma maccanni and common geckos Hoplodactylus maculatus kept in captivity gave birth, although gestation success in skinks depended on the basking regime that they were exposed to in captivity. Female McCann’s skinks exposed to basking temperatures for 3.5 days/week had lower gestation success (53% success) than skinks exposed to basking temperatures for 5 or 7 days/week (78–83% success). Similar numbers of female common geckos developed at least one viable offspring regardless of basking regime (3.5 days/week: 80% success; 5 days/week: 90% success; 7 days/week: 80% success). Most geckos that developed full-term embryos required inducement (see original paper for details). Clutch sizes were similar between different basking regimes for both skinks and geckos (see original paper for details). Pregnant female McCann’s skinks and common geckos were collected from the wild in November 2005 and October 2007 and kept in one of three basking regimes, with heat provided for: 8 hours/day for 3.5 days/week (17 skinks, 10 geckos), 5 days/week (18 skinks, 10 geckos) or 7 days/week (23 skinks, 10 geckos). Lizards were monitored until they gave birth and some lizards were induced when over-gestation was apparent using the hormone arginine vasotocin (see original paper for details). Gestation was considered a success when at least one viable offspring was delivered.

(Summarised by: Katie Sainsbury)
Use hormones and/or other drugs during captive-breeding programmes to induce reproduction/birth

A replicated study in 2005–2008 in laboratory conditions in South Island, New Zealand (Cree & Hare 2010) found that most wild pregnant common geckos Hoplodactylus maculatus brought into captivity were successfully induced after receiving the hormone arginine vasotocin (AVT). Most (number not given) of the 22 female geckos that received AVT delivered fully developed, viable offspring within 6 h of hormone injection. Pregnant common geckos were collected from the wild in November 2005 and October 2007. Initially, two females that were carrying fully developed embryos well beyond the expected term were induced with AVT (dissolved in 0.8% saline to deliver 150 ng/g of the hormone). A further 20 females that went beyond their expected term were induced.

(Summarised by: Katie Sainsbury)