Sexual reproduction is an evolutionary puzzle, and the persistence of males in particular can be perplexing.

 

Males do not directly contribute offspring, thus reducing the number of potential offspring by half as opposed to asexual reproduction. However, some organisms in the natural world are self-fertilizing hermaphrodites, meaning that they can fertilize their own eggs with their own sperm ("selfing"). While this provides reproductive assurance, there are other costs to this strategy, including higher susceptibility to parasites.

​

Some organisms have evolved an androdiecious system where selfing hermaphrodites and males co-exist with one another. At first, this may seem like an ideal solution, but one question still remains: "Why males?" If hermaphrodites can mate with themselves, why outcross (mate with a male)?

​

I am exploring these questions through a particularly unique fish species: the mangrove rivulus (Kryptolebias marmoratus). Native to the mangrove forests of Florida, the Caribbean, and Belize, the seemingly unassuming rivulus has a fascinating life history and suite of adaptations. Capable of surviving for two months out of water and tolerating various ranges of salinities, the rivulus is equipped for surviving the fluctuations that come with living in the mangrove forests. They have an androdiecious reproductive system, and typically the males only account for up to 2% of the population. So, why do these males persist? How do they convince hermaphrodites to mate with them?

​

My PhD research will use several approaches to investigate proximate and ultimate mechanisms of outcrossing in this unique system, including field surveys, behavioral studies, and microsatellite genotyping.

​

​