Seasonal changes of B-chromosome frequencies within the population of Apodemus flavicollis (Rodentia) on Cer mountain in Yugoslavia

Abstract

A change of B-chromosome frequencies in the populationof Apodemus flavicollis (Melchior, 1834) from Cer mountain inYugoslavia was studied. Five samples were collected during 1989.Specimens with Bs were present in all samples with frequenciesranging from 0.22 to 0.39. Differences between frequencies ofanimals with Bs in successive samples were not statisticallysignificant. The change in the population size (n) was positivelycorrelated with variation in frequency of animals with Bs (r-P =0.81), but negatively with frequency of Bs per B carrying animals(r-P = -0.65). A analysis of variance of external body measures andsome cranial characters showed no significant differences betweenanimals with and without Bs.