COMPARING PATTERNS OF GEOGRAPHIC-VARIATION IN CAVE CRICKETS BY COMBINING GEOSTATISTIC METHODS AND MANTEL TESTS

Geographic variation patterns of biological characters and environment al variables are compared by using a procedure employing multivariate analyses, production of contour maps by the kriging method with enclos ed validation of estimates, and Mantel tests to assess the significanc e of comparisons. As biological material we chose a sample of Dolichop oda cave crickets populations from Central-Southern Italy. The kriging technique provides estimates of the interpolation error for each true and estimated point. This profitable feature offers the opportunity t o use, with ascertained levels of confidence, the estimated z-scores f or further analysis and to compare data collected within the same area , but not exactly coincident in location or number. In such a way, we were able to use for subsequent comparisons by means of Mantel tests t he maximum number of data points for all data sets, which originally d iffered in sampling sites. The interpretation of the contour maps and their statistical comparison suggested that allozymes and epiphallus s hape data sets follow the phylogenetic pathways within the Dolichopoda populations, whereas variation in leg elongation is almost entirely u nder the control of an environmental gradient, synthetically described by the cave temperature.