GENETIC-STRUCTURE IN MIGRATORY AND NONMIGRATORY POPULATIONS OF BRAZILIAN FREE-TAILED BATS

The genetic compositions of a migratory population of Tudarida brasili ensis mexicana from Texas, two populations of this subspecies from Cal ifornia, one or both of which are nonmigratory, and three populations of T. b. cynocephala from Florida and Arkansas were compared using dat a from 22 allozymic loci. There were no statistically significant diff erences in allelic frequencies among the T. b. mexicana from Texas and California; the average genetic similarity among these populations wa s high ((I) over bar = 1.000, (S) over bar = 0.986), and standardized genetic variances calculated from the five most variable loci were low ((F) over bar(st) = 0.014). Despite their behavioral differences, mig ratory and nonmigratory T. b. mexicana appear to share a common gene p ool. The same loci showed close similarity ((I) over bar = 0.996, (S) over bar = 0.967), but apparently greater structure ((F) over bar(st) = 0.038) among the populations of T. b. cynocephala. The average genet ic similarity between the two subspecies ((I) over bar = 0.978, (S) ov er bar = 0.942) was within the range typically seen between geographic populations of the same subspecies. Frequencies of alleles in the sin gle population of T. b. cynocephala from Florida or in T. b. mexicana, suggest gene flow between these subspecies.