Reproduction in a Parthenogenetic Lizard: With a Discussion of Optimal Clutch Size and a Critique of the Clutch Weight/Body Weight Ratio

Abstract

The reproductive cycle of captive parthenogenetic lizards (Cnemidophorus uniparens) was analyzed from ovulation until hatching. Variables measured were amount of yolk per oocyte, amount of water absorbed in utero and during incubation, weights of the eggs at all stages of development, weights of the female before and after laying, and clutch size and weight relative to body weight. The mean weight of oocytes at ovulation was .33 g and that of eggs at oviposition was .59 g. Mean egg weight did not differ significantly between natural clutches (.58 g) and laboratory-produced clutches (. 56 g). The mean maximum weight of eggs during incubation was 1.28 g. The weight of neonates at hatching was .59 g and that of the egg remnants was .47 g. Mean incubation period was 50.3 days. Mean egg weight was greater in small clutches than in large ones. Large females developed a larger number of eggs per clutch and heavier clutches than did small females. However, small females produced heavier clutches relative to their body weight than large females. Therefore, relative reproductive investment is greater in small animals.