The sensory drive theory of speciation predicts that populations of the same species inhabiting different environments can differ in sensory traits, and that this sensory difference can ultimately drive speciation. However, even in the best-known examples of sensory ecology driven speciation, it is uncertain whether the variation in sensory traits is the cause or the consequence of a reduction in levels of gene flow. Here we show strong genetic differentiation, no gene flow and large echolocation differences between the allopatric Myanmar and Thai populations of the world's smallest mammal, Craseonycteris thonglongyai, and suggest that geographic isolation most likely preceded sensory divergence. Within the geographically continuous Thai population, we show that geographic distance has a primary role in limiting gene flow rather than echolocation divergence. In line with sensory-driven speciation models, we suggest that in C. thonglongyai, limited gene flow creates the suitable conditions that favour the evolution of sensory divergence via local adaptation.

The population size, distribution, threats and conservation status of 2 bat species included as 'endangered' in the IUCN Red List were assessed in Thailand and Myanmar. Craseonycteris thonglongyai Hill, 1974 and Hipposideros turpis Bangs, 1901 are both rare and poorly known cave-dwelling species, which have restricted distributions and small population sizes. Surveys of the 2 species were conducted in a large number of locations including previously reported sites and potential new locations. Colony size was counted at currently known localities, and population size was estimated. The known distribution and population are larger than in previous estimates, but both species still remain threatened by roost disturbance and the destruction of foraging habitat. Clarification of the taxonomic status of allopatric populations within each species is urgently required.

No abstract

No abstract

The bumble-bee bat (Craseonycteris thonglongyai) is an endangered species with a limited distribution range and a suspected declining population. Of the 30 microsatellites developed and tested in C. thonglongyai, 16 were amplified in two multiplex polymerase chain reactions (PCRs). Based on genotypes of 64 individuals from two populations, expected heterozygosities, averaged 0.50 in Myanmar and 0.61 in Thailand. Only one pair of loci showed linkage disequilibrium in one population and no deviation from Hardy-Weinberg equilibrium was detected. This set of 16 microsatellites will be useful to study population structure and gene flow in C. thonglongyai.