Functional significance of posthatching residual yolk in the lizard, Calotes versicolor

Abstract

A study was undertaken to find the role of residual yolk in maintenance and growth in newborn hatchlings of the lizard Calotes versicolor. Hatchlings (N = 90) of C. versicolor were obtained by incubating eggs (from six lizards) on moist sand at ambient temperature in the laboratory. Equal number of hatchlings from each clutch was assigned to each of the three groups. One group of hatchlings was fed daily for 10 days, whereas another group was not fed for the same period. Hatchlings that were fed grew significantly larger, both in snout-vent length (SVL) and body mass compared to the unfed individuals. Unfed hatchlings lost body mass although their SVL increased over the course of experiment. Residual yolk mass declined significantly in both fed and unfed hatchlings compared to the initial controls. Interestingly, fed hatchlings possessed less residual yolk than the unfed counterparts at the end of the experiment. Faster use of residual yolk in the fed hatchlings may be associated with higher metabolic rate/SDA after feeding. It is suggested that, in C. versicolor, residual yolk promotes growth of hatchlings, and it is also used as an energy source for sustenance under situations of scarcity of food or starvation.