DEVELOPMENTAL STABILITY AND POPULATION-DYNAMICS IN THE COMMON SHREW, SOREX-ARANEUS

We examine temporal variation in measures of developmental stability, such as the degree of fluctuating asymmetry and the number of phenotypic deviants per individual, in three populations of the common shrew Sorex araneus L. by using several characters of skeletal morphology. We compare a population from central Siberia with a high-amplitude 4-yr cycle with a population from southern Finland with noncyclic dynamics. The level of developmental stability varies significantly among the years in both populations. In the cyclic population in Siberia, developmental stability is highly correlated with population density, suggesting that in this case high density (or something related to it) is the most important negative factor affecting breeding females. In the noncyclic population in southern Finland we find no correlation between developmental stability and density. In both cyclic and noncyclic populations, developmental stability correlates positively with breeding success, indicating that breeding success is affected by the physiological condition of breeding females. Another relationship is found between developmental stability and natal dispersal (in eastern Finland), the rate of natal dispersal being highest when developmental stability is lowest. Developmental stability may be used as another population parameter, providing integrated information on the various factors that may adversely affect breeding females in natural populations.