Allometry of clutch and neonate sizes in monitor lizards (Varanidae : Varanus)

This paper analyzes data from the published literature with the addition of some new information to explore the relationship between varanid body size and reproductive biology. Incubation time for varanid eggs is positively c orrelated with egg mass, neonate snout-vent length (SVL), and maximum adult snout-vent length (SVLmax). Incubation period of heavier eggs is proportio nally less than for smaller eggs at 30 C. SVLmax is positively correlated w ith egg mass, clutch size, clutch mass, neonate body mass, and neonate SVL, Neonates of larger species have longer sVL but are smaller as a proportion of SVLmax than for smaller species. Clutch sizes are larger and more varia ble for larger species; however, clutch sizes for larger species relative t o SVLmax are smaller than for smaller species. The intraspecific influence of maternal SVL on clutch size is greater than the interspecific influence of SVLmax on clutch size. These results suggest there are greater fitness a dvantages for smaller species having relatively larger offspring than for l arger species, which concurs with results for snakes and other genera of li zards, as wed as optimal offspring size theory. Reproductive output also ap pears to be influenced by maternal abdominal volume. Analysis of phylogenet ically corrected data generally concurs with patterns evident in the nonphy logenetically corrected data. Body size has a much greater influence on rep roductive output of Varanus than phylogeny.