A modified yolk biopsy technique improves survivorship of turtle eggs

Nongenetic maternal contributions, such as steroid hormones, have received much attention in recent years because they have the potential to influence offspring phenotype. Research in oviparous taxa has demonstrated that there is among-species variability in their response to these maternal contributions. However, studies in chelonians and crocodilians have been hampered by the fact that techniques involving egg manipulations that breach the eggshell routinely result in massive egg mortality. In this study, we present an improved yolk manipulation technique that resulted in increased egg survival (in excess of 70% survival) in the red-eared slider turtle (Trachemys scripta) and that may be broadly applicable to other species. By elevating survival to a level on par with other oviparous taxa, this method permits a more thorough exploration of reptilian egg physiology and allows for studies that examine traits in both the egg and the resulting hatchling.