Meeting Abstract
Triops longicaudatus and Streptocephalus mackini are two crustaceans which cohabitate ephemeral freshwater pools throughout the arid Southwestern USA. They both lay desiccation-resistant eggs that disperse passively to new hydrologically isolated environments. The extent of genetic differentiation among the regions is of perennial interest in animals that live in such isolated habitats. This study estimated the amount of gene flow these two species undergo within and between regions. Populations in six natural ephemeral pools located in two different regions of the Sonoran Desert were sampled. Three of the pools are located in central Arizona near the Phoenix metropolitan area, whereas the remaining three are located roughly 250 kilometers away in southeastern Arizona near the city of Willcox. The extent of gene flow was assessed through the use of neutral markers to estimate genetic variability within and among pools. The outcome of this work has implications for the potential for local adaptations in these species. One implication that the outcome will inform our understanding of the extent to which opsin expression in the eyes of these crustaceans is developmentally plastic versus regionally adapted. In other animals with multiple spectral classes of opsins, opsin expression patterns may covary with the properties of the light environment in which they develop. Light environments in the ephemeral pools studied exhibit a high degree of regional variation. Potential links between the observed patterns of genetic differentiation among pools and the properties of their opsins will be discussed.
