A TEST OF THE CENTRAL-MARGINAL MODEL USING SAND SCORPION POPULATIONS (PARUROCTONUS-MESAENSIS, VAEJOVIDAE)

The central-marginal model proposes marginal populations contain a low er density of individuals, lower levels of genetic variation, and are more isolated than populations in the center of a species range. Previ ous tests of the model used Drosophila, organisms capable of extended dispersal. We test the central-marginal model with scorpions, organism s with restricted dispersal abilities. We measured genetic variation t hrough allozyme analysis of eight loci (five polymorphic, three monomo rphic) to obtain estimates of heterozygosity. We compared differences between the two types of populations with a split-plot ANOVA. We also compared central and marginal populations using standard parametric te sts. We found marginal populations contain lower genetic variation tha n central populations. These populations may be important as models in conservation to study the effects of fragmentation.