Influence of incubation temperature and substrate on eggs and embryos of the garden lizard, Calotes versicolor (Daud.)

Published source details Radder R.S., Shanbhag B.A. & Saidapur S.K. (2002) Influence of incubation temperature and substrate on eggs and embryos of the garden lizard, Calotes versicolor (Daud.). Amphibia-Reptilia, 23, 71-82.
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This study is summarised as evidence for the following.

	Action	Category
	Relocate nests/eggs for artificial incubation: Lizards Action Link
	Relocate nests/eggs for artificial incubation: Lizards Action Link

Relocate nests/eggs for artificial incubation: Lizards

A replicated, randomized, controlled study in 1997–1998 in Karnataka, southwest India (Radder et al. 2002) found that when eggs from wild-caught garden lizards Calotes versicolor were artificially incubated, hatching success was lower at higher incubation temperatures but was not affected by short exposures to high temperatures. Hatching success was lower at 35°C (33 of 59, 53%) and 33°C (36 of 61, 59%) than it was at 30°C (49 of 55, 89%) and at ambient temperatures of 27°C (138 of 148, 93%). Hatching success remained similar when eggs were exposed to short periods at 35°C (1 h/day: 15 of 16, 94%; 3 h/day: 14 of 15, 93%) compared to when eggs were incubated at ambient temperatures of 27°C (15 of 15, 100%). In 1997–1998, gravid female lizards were caught (number not given) and when they reached late gravidity eggs were removed from the oviduct (method not given). Eggs from 15 clutches were split between the treatment temperatures (55 eggs at 30°C, 61 at 33°C and 59 at 35°C) and ambient temperatures (148 eggs at 27°C). A further 46 eggs from three clutches were incubated at 27°C and exposed to 35°C for 1 h/day (16 eggs), 3 h/day (15 eggs) or kept at ambient temperatures (15 eggs). All eggs were incubated in black clay soil, and moisture levels were topped up every two days.

(Summarised by: William Morgan)
Relocate nests/eggs for artificial incubation: Lizards

A replicated, randomized study in 1998 in Karnataka, southwest India (Radder et al. 2002) found that when eggs from wild-caught garden lizards Calotes versicolor were artificially incubated, eggs incubated in cotton wool had lower hatching success than those incubated in soil or sand. Hatching success was lower for eggs incubated in cotton wool (59 of 68, 84%) compared to those incubated in soil (59 of 61, 95%) or sand (84 of 87, 96%). Across all treatments, the average incubation period stayed the same (69 days), and three measures of hatchling size did not differ significantly (body mass, snout-vent length and tail length). In 1997–1998, gravid female lizards were caught (number not given) and when they reached late gravidity eggs were removed from the oviduct (method not given). In 1998, eggs from 15 clutches were incubated in either cotton wool (68 eggs), wet black clay soil (61 eggs) or sand (87 eggs). Eggs were incubated at ambient temperatures of 27°C. Every two days, moisture levels were topped up and new cotton wool was provided.

(Summarised by: William Morgan)