The core of this project focuses on monitoring the phenotypic and genotypic evolution of experimental and natural hybrid populations of swordtails for ten generations. To get a clear understanding of how evolution shapes genome wide ancestry and the distribution of species-specific alleles at functional loci during early generations of hybridization, it's important to monitor these populations using experimental crosses. Eight replicate 2000 L mesocosm stock tanks were built at high (1514 m), intermediate (980 m), and low (186 m) elevations near the CICHAZ field site were seeded with Xiphophorus birchmanni – X. malinche F1 hybrids.
The F1s were generated by crossing X. malinche females with X. birchmanni malesin stock tanks at CICHAZ, a research station in Calnali, Mexico. Tanks at higher elevations experience cooler water temperatures. Our experimental design thereby allows us to characterize how ecological selection shapes genotypic and phenotypic differences in thermal tolerance across hybrid populations exposed to different temperature regimes.
The data contained in these files include recorded water temperature (in Celsius), taken every six hours from three stock tanks at low (186 m: STL), medium (980 m: STM), and high (1514 m: STH) elevations, along with three natural river sites. File Natural.csv contains the natural sites and the file Stock Tanks.csv contains the corresponding natural sites. Acuapa (ACUA) is paired with STL, Aguazarca (AGZC) is paired with STM, and Tlatemaco (TLMC) is paired with STH.