The Research On Speciation And Intra-specific Differentiation Of Miniopterus Fuligionsus

Speciation is the essential question of evolution, and species differentiation is the premise and foundation to form a new species. The research on the process and driving force of phenotype and genetic differentiation will help to reveal the reason and mechanism for speciation. Most classic speciation studies applied historical retrospection to study the speciation of the species have been formed. This ‘spyglass’ usually can not reveal the early process of speciation. Recently, a novel comprehensive theory which combined ‘spyglass’ and ‘magnifying glass’ to study speciation has been developed, the latter reveal the initial species differentiation through the research on the lower taxonomic category, such as population differentiation. This theory will contribute to reveal process and mechanism of speciation preferably.The taxonomic status of Miniopterus fuligionsus(Chiroptera: Miniopterinae) has been confirmed recently, but the reasons of species differentiation between Miniopterus fuligionsus and its sibling species, the differentiation level of intra-species and evolutionary drive are not clear. In this study, we combined ‘restrospective spyglass approch’ and ‘magnifying glass’ to study speciation of Miniopterus fuligionsus and including the analysis of genetic, morphology, echolocation, environment and geography data to aim at: 1) explained the genetic differentiation status quo and species differentiation history of Miniopterus fuligionsus and its sibling species Miniopterus magnater; 2) determined the differentiated level of morphological character and echolocation of M. fuligionsus and M. magnater; 3) revealed the polulation genetic structure and evolutionary history of M. fuligionsus; 4) revealed the differentiation level and driving force of morphological character and echolocation between different population of M. fuligionsus; 5) combined the results of differentiation between M. fuligionsus and M. magnater and within M. fuligionsus explained whether the species evolution conform to the theory of allopatric speciation or ecological choice hypothesis or sensory driving hypothesis.Mitochondrial DNA gene genealogies revealed that the two species are sister species and formed a monophyletic lineage, the most recent common ancestor was dated to the early stage of the Quaternary glacial period(ca. 1.69–2.37 Ma), and population expansion event was inferred for populations of M. fuliginosus and M. magnater at the early stage of the last interglacial period(0.14 Ma and 0.12 Ma, respectively). Strong genetic structure was obtained from mtDNA data but not microsatellite data, nuclear DNA introgression/hybridization may take place between two species. The analysis of population genetic data of M. fuligionsus indicated that four lineages exist in M. fuligionsus, but with low bootstrap and posterior probability support. And every lineages is not corresponding to any geographic population. The data of mtDNA and microsatellite indicated that there is no significant genetic structure. The genetic distance based on the two markers has no significant correlation with geographical distance.The differentiation results of morphology and echolocation between M. fuligionsus and M. magnater indicated that the most morphological and echolocation parameter showed significant difference and the analysis of multidimensional scaling revealed two distinct groups,, which was consistent with the classification of mtDNA marker. But obvious overlaps exist in morphological parameters and echolocation parameters between the two species. Simultaneously, Nested analysis of variance show that some of the external morphological and echolocation parameters and most of the skull parameters result from individual whthin population. These suggest that weaker differentiation level between the two species.The differentiation results of morphology and echolocation among different population of M. fuligionsus indicated that the most morphological character and the start frequency and peak frequency of echolocation parameter showed significant difference, but exist obvious overlaps, the significant difference only find between few populations. These results indicated that though significant difference was observed between different populations, but only show small difference. Simultaneously, the variation of external morphology and skull are not associated with microsatellite genetic distance, mtDNA genetic distance, geographic distance and climate distance, and the body size are not associated with latitude and altitude. Simultaneously, the variation of echolocation calls is not associated with body, annual rainfall, relative humidity, geographic distance and mtDNA genetic distance, only correlative with microsatellite genetic distance.In this study, the genetic differentiation results of M. fuligionsus and M. magnater indicated that the geographical isolation caused by Quaternary glacial period may contribute to the genetic differentiation between the two species. The M. fuligionsus in China did not have significant genetic structure indicated that this species have long-range migratory and dispersal abilities, and suggested that the geographical isolation which caused speciation of M. fuligionsus should be at large geographic scales. The morphological and echolocation parameter showed significant difference between M. fuligionsus and M. magnater, but with large overlap. And variation of morphology and echolocation of M. fuligionsus are not associated with environmental factors. The differentiation of echolocation within species is the result of genetic differentiation but not origin. All these results suggested that ecological selectivity and sensory drive may not be the reason of speciation of M. fuligionsus. The strong dispersal abilities is the main reason of low differentiation level of intra-species heredity and morphology. Our study support the theory of allopatric speciation, but not conform to ecological choice hypothesis and sensory driving hypothesis.