Alligator mating behavior and nesting ecology

David Scott 6

Recently a group of us examined multiple paternity in gators from Rockefeller Wildlife Refuge (RWR) in south-west Louisiana. At RWR nests are surveyed on a yearly basis and we looked at over 100 nests from 1995-2005. We screened hatchlings across a panel of microsatellites (almost 2000 hatchlings!) and found multiple paternity in 51% of clutches. What was extremely fortuitous--and which demonstrated how critical long-term data are-- was that for ten females we were able to sample nests from multiple years. For some females we sampled nests from three different years. Females don’t lay eggs every year so we captured a good per cent of their nests over the time period. What really surprised us is that seven (70%) of these females exhibited long-term mate fidelity, with one female mating with the same male in 1997, 2002, and 2005. Five females exhibited partial mate fidelity---they had at least one multiple paternity nest and thus mated with the same male over multiple years, but not exclusively. Our finding of partial mate fidelity is the first for any crocodilian species. This result was surprising on many levels but partly because the area we worked in has literally 1000‘s of alligators and the males home range size is very large so it raises many questions about the mating strategy and potential for recognition and mate choice.

Now the Lance Lab is collaborating with Ben Parrott, Thomas Rainwater, and the folks at the Yawkey Wildlife Center Hertigae Preserve to look at gator mating behavior and nesting ecology there. Phil Wilkinson has been monitoring nest sites there for over years and in many cases are able to catch mom at the nest but often only have DNA samples from eggs. We have tissue samples from a lot of the adults in the area so we are using microsatellites to try and assign maternity to each nest and then also determine whether multiple paternity and/or mate fidelity occurs in this population. This project has been a struggle because the gator population here has incredibly low allelic diversity. We are developing a whole new suite of loci to try and get enough power to answer these questions. For those of you fellow Red Sox fans out there the "Yawkey" of the wildlife center is indeed the same Yawkey!

Ben Parrott Eggs

Ben Parrott collecting eggs

The content and opinions expressed on this web page do not necessarily reflect the views of nor are they endorsed by the University of Georgia or the University System of Georgia. Jason O'Bryhim & Stacey Lance 2013