Locomotor endurance predicts differences in realized dispersal between sympatric sexual and unisexual salamanders

Dispersal is the central mechanism that determines connectivity between populations yet few studies connect the mechanisms of movement with realized dispersal in natural populations. To make such a link, we assessed how physiological variation among individuals predicted dispersal in natural populations of unisexual (all-female) and sexual Ambystoma salamanders on the same fragmented landscape in Ohio.
Specifically, we assessed variation in a trait that influences long-distance animal movement (locomotor endurance) and determined whether variation in endurance matched patterns of realized dispersal assessed using genetic assignment tests. A possible mechanism for why unisexuals would have lower locomotor endurance than a sympatric sexual species (Ambystoma texanum) is the potential energetic cost of evolutionarily mismatched mitochondrial and nuclear genomes within polyploid unisexuals.
We found that sexuals walked four times farther than unisexuals during treadmill endurance trials t...