RELATIONSHIPS AMONG BODY SIZE, CLUTCH SIZE, AND EGG SIZE IN THREE SPECIES OF OVIPAROUS SNAKES

Abstract

Many species of reptiles exhibit complex interrelationships among maternal body size, clutch size, and offspring size. Although female size and clutch size are often positively correlated, the effects of female size and clutch size on offspring size are still poorly understood. In this study, we examined these interrelationships for three species of oviparous snakes (Elaphe guttata, Trimeresurus flavoviridis, and T. okinavensis). Our data showed that increasing female body length was generally associated with higher clutch size and wider eggs. When adjusted for female length, increasing clutch size was negatively correlated with egg length (all species) and egg mass (except in E. guttata). Our data support portions of a model proposed to explain offspring size variation in lizards. Our data also support the prediction of optimal offspring size theory that clutch size and offspring size should be negatively correlated. The failure of many previous studies of reptiles to support this prediction may be the result of not controlling for female size when examining the relationship between clutch size and offspring size.