. Bonner zoologische Beiträge : Herausgeber: Zoologisches Forschungsinstitut und Museum Alexander Koenig, Bonn. Biology; Zoology. Geographie variation in the snow vole 131 ^"1 PRINCIPAL. PRINCIPAL COMP. 1 -2- Fig. 10: Projections of 13 samples of Austrian and Yugoslavian Microtus nivalis onto the first two principal components. Identifying numbers refer to sample areas (Fig. 1). Triangles — Alpine samples; dots — Dinaric samples; star — east Serbian sample. The relative braincase breadth (IND 2) showed no significant interpopulation variability. Since IND 2 broadly describes the skull sha
. Bonner zoologische Beiträge : Herausgeber: Zoologisches Forschungsinstitut und Museum Alexander Koenig, Bonn. Biology; Zoology. Geographie variation in the snow vole 131 ^"1 PRINCIPAL. PRINCIPAL COMP. 1 -2- Fig. 10: Projections of 13 samples of Austrian and Yugoslavian Microtus nivalis onto the first two principal components. Identifying numbers refer to sample areas (Fig. 1). Triangles — Alpine samples; dots — Dinaric samples; star — east Serbian sample. The relative braincase breadth (IND 2) showed no significant interpopulation variability. Since IND 2 broadly describes the skull shape, we can conclude from the results of univariate analysis that shape is less variable between samples than the size. Multivariate analysis Results from 13-sample principal component analysis are given in the plot of projec- tions of sample onto the first two principal components (Fig. 10). Size related characters are generally more important in determining the first principal component (Lemen 1983), and this is well obvious also from character loadings of the interlocali- ty variation in our snow vole samples. Length characters (CbL, RoL, DiL) con- tributed most to the first principal component by high positive values, while loC has a high negative loading for this component. Interorbital constriction is usually negatively correlated with age and size in voles, thus the smaller the interorbital con- striction, the larger the vole. Sample 12 had high negative loadings for the first prin- cipal component, and consequently snow voles from Galicica would be expected to be the smallest. This corresponds well with the results of univariate analyses. High positive values of the first principal component were found in geographic samples 1, 5, 6, 8, 9, and 11 which means that they are the largest. Samples 2, 3, 4, 7, 10, and 13 appeared to be intermediate in size. The second principal component is inter- preted as an indicator of shape similarity (Lemen 1983) i. e. the smaller
Size: 1939px × 1288px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookcoll, booksubjectbiology, booksubjectzoology
