Research Interests
Natural selection and genetic drift are expected to reduce the amount of genetic (and phenotypic) variation in natural populations – how variation is maintained in natural populations is therefore an evolutionary puzzle. I examine hypotheses that address this problem using the green swordtail, Xiphophorus helleri, which shows remarkable, inherited variation in many phenotypic traits (see photos!). Together with undergraduate students, I measure phenotypic variation in several morphological traits, examine the genetic basis of this variation, and test hypotheses about their adaptive value in the context of the swordtails' behavior and ecology.
My current main project focuses on exhaustively quantifying reproductive success and its phenotypic correlates of male and female green swordtails in a natural population in Belize. This project is conducted in collaboration with Drs Andrey Tatarenkov and John Avise (UC Irvine) and utilizes microsatellite markers to estimate parentage of the lab-reared offspring of wild-caught males and females.
Photos
 |
 |
| The Bladen Branch River. Swordtails inhabit both the main river and its many small tributaries. | Rainforest view from the satellite tower at the Belize Foundation for Research and Environmental Education (BFREE), where most of my research is conducted. |
 |
 |
A female green swordtail (Xiphophorus helleri) with black melanin-based spots. |
A female green swordtail (Xiphophorus helleri) without spots. |
 |
| Two green swordtail males that illustrate the variation in body size found in natural populations. (Females do not have the sword-like extension of the tail fin.) |