Invasive species are a major threat to biodiversity and ecosystem function, and are of increasing economic concern. Yet, ecologists have struggled to explain why some species succeed while others do not. One hypothesis is that a population with high genetic diversity should be able to adapt quickly to new environments, thus enhancing invasion success. The Mayan cichlid (Cichlasoma urophthalmus) is native to the Atlantic slope of Central America. It was first recorded in Everglades National Park in 1983 and is now well established throughout most of south Florida. I examined genetic structure of introduced and native populations of Mayan cichlids by examining the cytochrome b gene to evaluate the source and number of introductions.
Results/Conclusions
To date, we have collected 504 fish from within the Everglades, Mexico, Belize, Honduras and Guatemala. Travel to Belize and Nicaragua are planned to collect additional samples from the native range. Preliminary results indicated six cytochrome b haplotypes that can distinguish between samples from Mexico, Belize and Honduras (native range), and the Everglades (introduced range). Mexico and Belize displayed shared and unique haplotypes while South Florida haplotypes are completely distinct. Genetic variation within Mexico, Belize, and within sites of south Florida, significantly contributed to total genetic variation of Mayan cichlids. Variation between the native and introduced ranges was highest accounting for most of the total genetic variation. Preliminary results indicate that Mayan cichlids may have been introduced from a single or small number of sites in the native range, suggesting a population bottleneck upon introduction. These results show that cytochrome b can help to identify source populations for Mayan cichlid introductions in south Florida and determine genetic relationships within and between the native and introduced ranges.