Influence of X‐rays on incubation in tuatara, Sphenodon punctatus

Abstract

Eggs and hatchlings from female tuatara, Sphenodon punctatus, that were X‐rayed immediately before oviposition were compared with eggs and hatchlings from non‐X‐rayed females. Eggs were incubated at 18, 20 or 22°C, ‐230 or ‐400 kPa water potential, and either half buried or completely buried in the incubation substratum. Incubation times and water fluxes of eggs were recorded. Hatchlings were weighed and measured. Total oxygen consumption of eggs incubating on the surface of substrata at ‐230 kPa and 18, 20 and 22°C was measured. At 20cC and buried at ‐230 kPa, X‐rayed eggs absorbed more water than non‐X‐rayed eggs, although the resulting hatchlings were not significantly different in size and mass. No other egg or hatchling parameter was significantly influenced by X‐rays. The only deformed hatchlings emerged from eggs that had not been X‐rayed. Thus, with the exception of possible germ cell damage, which could not be assessed in this study, we conclude that radiography of females with oviductal eggs had no affect on embryonic development.