Analysis of asymmetries in the African fruit bats Eidolon helvum and Rousettus egyptiacus (Mammalia : Megachiroptera) from the islands of the Gulf ofGuinea. II. Integration and levels of multivariate fluctuating asymmetry across a geographical range

Using a set of cranial morphometric characters, trends of variation in mult ivariate fluctuating asymmetry were evaluated and compared in populations o f African fruit bats Rousettus egyptiacus and Eidolon helvum from the Gulf of Guinea islands, and the adjacent mainland. Levels of asymmetry were comp ared across populations and species, and significant differences were found in both comparisons. Differences coincided with species-specific patterns of morphological and genetic differentiation. Concordance of correlation ma trices of asymmetry was also compared. Results were significant; concordanc e is hypothesized to be a by-product of developmental processes that produc e the 'fox-like' morphology shared by these species. Consistency of asymmet ry patterns suggests that the developmental pathway producing it is highly canalized. A prediction of the above hypothesis is that a radical change in the 'fox-like' structural pattern would result in breakage of the asymmetr y parameter associated with it.