Faculty Advisor

Stacey, Weiss

Area of Study

Science and Mathematics

Publication Date

Summer 2015


Eggs laid by the Sceloporus virgatus lizard are exposed to a variety of potentially protective microorganisms when passed through the cloaca, the opening at the end of both the reproductive and digestive tracts. Past data have indicated that eggs dissected out of the female before passing through the cloaca often have decreased hatching success, potentially due to the lack of protective bacteria on the dissected eggshell surface. This study examined the microorganisms found on both laid and dissected eggs at 0 weeks of incubation, as well as microbial and fungal content on the eggshells after 3 weeks of incubation in a non-sterile environment. The eggshells were swabbed and plated onto media to observe any visible growth at 0 and 3 weeks of incubation. The morphology of the eggshells was also studied with scanning electron microscopy to determine visual differences in microbial and fungal content between the eggs. A lesser proportion of dissected eggs exhibited microbial growth at 0 weeks of incubation, while at 3 weeks of incubation fungal growth was found on mainly dissected eggs. The results support the claim that laid eggs passed through the cloaca may be exposed to microorganisms that are protective against fungi in the incubation environment.


University of Puget Sound