Intraspecific comparison of population structure, genetic diversity, and dispersal among three subspecies of Townsend’s big-eared bats, Corynorhinus townsendii townsendii, C. t. pallescens, and the endangered C. t. virginianus (original) (raw)
Related papers
Migration and dispersal patterns of bats and their influence on genetic structure
Mammal Review, 2013
Bats are important ecosystems service providers, make a significant contribution to biodiversity and can be important pests and disease vectors. In spite of this, information on their migration and dispersal patterns is limited. 2. In temperate bats, migration is most evident in females. This reflects seasonal differences in their habitat requirements, and the fact that seasonally suitable sites can be geographically distant. Tropical bats mainly migrate to track variation in food availability. 3. Little direct information is available on the patterns and drivers of bat dispersal, although drivers may include mate competition and inbreeding avoidance. In many temperate species, differential energy requirements and local resource competition among the sexes drive sexual segregation in the summer: females remain philopatric to their natal region, and frequently to their natal colony, while males disperse. In contrast, many tropical Pteropodidae form single-male/multifemale groups in which local resource defence contributes to female-biased or all-offspring dispersal from the natal site. 4. Population genetic studies are the most common source of evidence used to infer the spatial dynamics of bats. As expected, migratory species tend to have less genetically structured populations over large geographical scales due to mating outside of breeding areas, weak migratory connectivity and long-distance movements. In contrast and as expected, populations of sedentary species tend to be more differentiated at smaller geographical scales. 5. Despite this general pattern, a range of factors, including historical events, dispersal capabilities, and behavioural, ecological and geographical barriers, are implicated in the genetic partitioning of bat populations, irrespective of movement patterns. These factors limit the study of bat movements using only genetic methods. 6. Combining population genetics with other methods, such as mark-recapture, tracking or stable isotope analysis, should provide more insight into the movements of these ecologically and economically important species. bs_bs_banner
Exploring population genetic structure in three species of Lesser Antillean bats
2004
We explore population genetic structure in phyllostomid bats ( Ardops nichollsi , Brachyphylla cavernarum and Artibeus jamaicensis ) from the northern Lesser Antilles by investigating the degree to which island populations are genetically differentiated. Our hypothesis, that the island populations are genetically distinct because of a combination of founding events, limited migration and genetic drift exacerbated by catastrophe-induced fluctuations in population size, is derived from a priori hypotheses erected in the literature. The first prediction of this hypothesis, that within each species island populations are monophyletic, was tested using a parametric bootstrap approach. Island monophyly could not be rejected in Ardops nichollsi ( P = 0.718), but could be rejected in B. cavernarum ( P < 0.001) and Artibeus jamaicensis ( P < 0.001). A second prediction, that molecular variance is partitioned among islands, was tested using an AMOVA and was rejected in each species [ Ardops nichollsi ( P = 0.697); B. cavernarum ( P = 0.598); Artibeus jamaicensis ( P = 0.763)]. In B. cavernarum and Artibeus jamaicensis , the admixture in mitochondrial haplotypes from islands separated by > 100 km of ocean can be explained either by interisland migration or by incomplete lineage sorting of ancestral polymorphism in the source population. As an a posteriori test of lineage sorting, we used simulations of gene trees within a population tree to suggest that lineage sorting is an unlikely explanation for the observed pattern of nonmonophyly in Artibeus jamaicensis ( P W < 0.01; P SE = 0.04), but cannot be rejected in B. cavernarum ( P W = 0.81; P SE = 0.79). A conservative interpretation of the molecular data is that island populations of Artibeus jamaicensis , although isolated geographically, are not isolated genetically.
2010
a bstract. The azorean bat (Nyctalus azoreum), the only endemic mammal of the azores archipelago (Portugal), diverged recently from its mainland relative, the leisler's bat (N. leisleri). although the two species are phenotypically very different, mtDNa studies detected very low genetic divergence between them, which could question the validity of the species status of N. azoreum. in order to assess the genetic variability in each species and check for present levels of gene flow between the two taxa, eight microsatellite loci were genotyped and analysed. The results indicated lower genetic diversity in the insular species. Many unshared alleles were found between the two species and no evidence of migrants, which provides strong support against any contemporary gene flow between them. The species status of the azorean bat is discussed in the light of the cohesion species concept, and we conclude that it is an isolated species with a high conservation value.
Genetic diversity, historic population size, and population structure in 2 North American tree bats
Journal of Mammalogy, 2015
Migratory tree bats comprise the majority of casualties at wind energy facilities across North America and some species, like Lasiurus borealis, are suspected to be in decline. We took advantage of the large numbers of L. borealis and L. cinereus salvaged during fall migration at 1 wind farm in Texas and 3 wind farms in Minnesota to evaluate the ability of current genetic methods to estimate population size and detect genetic bottlenecks in these species. Using DNA extracted from wing membrane tissue samples, we genotyped 439 L. borealis and 246 L. cinereus at 6 microsatellite loci and a 550 bp segment of the mitochondrial COI gene. Both microsatellite loci and mitochondrial haplotypes showed high levels of genetic diversity in each species. Historical estimates of N e were large for both species. Estimates of N Ef from the COI gene were almost 2 times higher for L. borealis than L. cinereus, whereas estimates utilizing microsatellite heterozygosity were higher for L. cinereus. We found a strong signal of rapid historical population growth and range expansion in L. borealis, but not in L. cinereus. The majority of our estimates of current N e had upper 95% confidence intervals that encompassed infinity. There is some indication from contemporary estimates of N e that L. borealis may have a lower current N e than historical estimates and that L. cinereus may currently have a very large N e. We found no genetic evidence of recent population declines and no evidence of population structure in either species. Genetic monitoring of migratory tree bats, specifically for the purpose of detecting population declines caused by wind turbine mortality, may be impractical due to the large effective population sizes and high levels of gene flow in these species. Future efforts should focus on developing genomic resources for these species, obtaining better estimates of mutation rates, and conducting range-wide population genetic studies in order to better estimate historical and current population sizes.
PLoS ONE, 2011
Observed patterns of genetic structure result from the interactions of demographic, physical, and historical influences on gene flow. The particular strength of various factors in governing gene flow, however, may differ between species in biologically relevant ways. We investigated the role of demographic factors (population size and sex-biased dispersal) and physical features (geographic distance, island size and climatological winds) on patterns of genetic structure and gene flow for two lineages of Greater Antillean bats. We used microsatellite genetic data to estimate demographic characteristics, infer population genetic structure, and estimate gene flow among island populations of Erophylla sezekorni/E. bombifrons and Macrotus waterhousii (Chiroptera: Phyllostomidae). Using a landscape genetics approach, we asked if geographic distance, island size, or climatological winds mediate historical gene flow in this system. Samples from 13 islands spanning Erophylla's range clustered into five genetically distinct populations. Samples of M. waterhousii from eight islands represented eight genetically distinct populations. While we found evidence that a majority of historical gene flow between genetic populations was asymmetric for both lineages, we were not able to entirely rule out incomplete lineage sorting in generating this pattern. We found no evidence of contemporary gene flow except between two genetic populations of Erophylla. Both lineages exhibited significant isolation by geographic distance. Patterns of genetic structure and gene flow, however, were not explained by differences in relative effective population sizes, island area, sex-biased dispersal (tested only for Erophylla), or surface-level climatological winds. Gene flow among islands appears to be highly restricted, particularly for M. waterhousii, and we suggest that this species deserves increased taxonomic attention and conservation concern.
Molecular Phylogenetics and Evolution, 2007
Migratory divides are thought to facilitate behavioral, ecological, and genetic divergence among populations with different migratory routes. However, it is currently contentious how much genetic divergence is needed to maintain distinct migratory behavior across migratory divides. Here we investigate patterns of neutral genetic differentiation among Blackcap (Sylvia atricapilla) populations with different migratory strategies across Europe. We compare the level of genetic divergence of populations migrating to southwestern (SW) or southeastern (SE) wintering areas with birds wintering in the British Isles following a recently established northwesterly (NW) migration route. The migratory divide between SW and SE wintering areas can be interpreted as a result of a re-colonization process after the last glaciation. Thus we predicted greater levels of genetic differentiation among the SW/SE populations. However, a lack of genetic differentiation was found between SW and SE populations, suggesting that interbreeding likely occurs among Blackcaps with different migratory orientations across a large area; therefore the SW/SE migratory divide can be seen as diffuse, broad band and is, at best, a weak isolating barrier. Conversely, weak, albeit significant genetic differentiation was evident between NW and SW migrants breeding sympatrically in southern Germany, suggesting a stronger isolating mechanism may be acting in this population. Populations located within/near the SW/SE contact zone were the least genetically divergent from NW migrants, confirming NW migrants likely originated from within the contact zone. Significant isolation-by-distance was found among eastern Blackcap populations (i.e. SE migrants), but not among western populations (i.e. NW and SW migrants), revealing different patterns of genetic divergence among Blackcap populations in Europe. We discuss possible explanations for the genetic structure of European Blackcaps and how gene flow influences the persistence of divergent migratory behaviors.