T. Yamashita et Ga. Polis, A TEST OF THE CENTRAL-MARGINAL MODEL USING SAND SCORPION POPULATIONS (PARUROCTONUS-MESAENSIS, VAEJOVIDAE), The Journal of arachnology, 23(2), 1995, pp. 60-64
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.