Sexual Dimorphism and Female Reproductive Characteristics in the Oriental Garden Lizard, Calotes versicolor, from Hainan, Southern China

Abstract

Males and females of the oriental garden lizard (Calotes versicolor) from a population in Hainan, southern China, differed in head size at hatching: males had larger heads than females. This dimorphism was slightly more pronounced in adults than in hatchlings. Hatchlings had larger heads but shorter tails relative to snout–vent length (SVL) than subadults and adults. When SVL was held constant, tail length of subadults and adults of the same sex was similar. Adult lizards were not sexually dimorphic in body size (SVL), but males possessed longer tails than females at the same SVL throughout their size range. The smallest and largest reproductive females in our sample were 78.9 and 103.8 mm SVL, respectively. Females in our laboratory (Hangzhou, eastern China) laid multiple clutches from April to June. Clutch size, clutch mass, and egg mass varied from 3 to 14 (mean = 9.0) eggs, 1.58 to 6.47 (mean = 4.65) g, and 0.45 to 0.61 (mean = 0.52) g, respectively. Clutch size and clutch mass were both positively correlated with female SVL. Egg mass was not correlated with female SVL even when clutch size was held constant using a partial correlation analysis. Clutch size was not correlated with female condition when female SVL was held constant. Egg length, egg width, and clutch size were not correlated with each other when the remaining variable was held constant. Egg mass was not correlated with clutch size when female SVL was kept constant. Larger-sized C. versicolor females increased reproductive output primarily through production of more eggs (and hence heavier clutches).