Q: What’s the broader significance of all this?
A: It’s multifold. We have good support for the evolution of egg-protective cloacal microbes in one lizard species. But this mechanism of egg-protection could potentially be very wide-spread among oviparous, or egg-laying, animals. If so, it will open up new ways to think about the role of microbes on their hosts. The field of microbial ecology is rapidly advancing, and we’re learning so much about host-microbe coevolutionary relationships. Since I’m trained as a behavioral ecologist, I’m very interested in investigating how my microbial work intersects with theory about the evolution of parental care—or lack thereof—and of female sexual signaling. For instance, might females advertise their high quality, egg-protective microbiome to potential mates? It’s also critical to our field that we’re studying a diversity of host species, environmental pressures, and adaptations—and, so far, lizards tend to be underrepresented in microbial ecology. So even the basic descriptive components of our work are important.
Q: Is there conceivably any relevance to humans?
A: Yes. Since we’re looking at antifungal properties of cloacal bacteria, our work could potentially identify new antifungal agents. That aspect isn’t what drives my intellectually curiosity, but it’s the only time in my career when my research could have direct impacts on human health.
Q: How does one measure bacteria and fungus on lizard eggs, anyway?
A: It’s actually pretty fun. To catch the lizards, we use a lasso slipknot—a fishing line at the end of an extendable fishing pole—and we get a loop around the lizards’ neck and flick up. Then we pull them out of the loop and take a swab and gently twirl it around in the cloaca to collect a microbial sample. While the lizard is in hand, we also take basic measurements—sex, mass, length—and one of our undergraduates, Alexi Ebersole, takes a little snip of their tail tissue, so we can learn about their diets using stable isotope analyses. Then we put a small dab of paint on their back and release them. Then in the lab, we can culture the material from the swab in a petri dish, see what grows, isolate it, extract and sequence the DNA, and use databases to find its identity. We also use high-throughput sequencing to identify all the microbes in the sample; this requires advanced bioinformatics to give us measures of microbial diversity and composition.