CHARACTER DISPLACEMENT IN THE PSAMMOPHILE GERBILLIDAE OF ISRAEL

The possibility that community-wide character displacement exists among the gerbiline rodents that live in the sand dunes of the Mediterranean coastal plain, the northern Negev and the Arava (southern Negev), Israel, was examined. This was done by searching for equal size ratios in the greatest length of the skull (GTL) and the length of the upper tooth row (UT) of museum specimens of mine species of gerbils which live in these communities. Barton-David tests show that unusual equality of size ratios of UT exist for the northern Negev community and for the GTL for the coastal dunes. It is suggested that the above results are an outcome of competition over food: the smaller species, which have shorter tooth row, specialize in feeding on seeds and the larger species, with longer UT, eat more vegetation. The possible reasons for the difference in the number of species in each community are discussed.