Do diversification models of Madagascar’s biota explain the population structure of the endemic bat Myotis goudoti (Chiroptera: Vespertilionidae)?

Abstract

Aim Three mechanisms have been proposed to explain the adaptive radiations and species diversifications of Madagascar's biota: the ecogeographical constraint, the riverine barrier and the micro-endemism models. On the intraspecific level, each model predicts different patterns of gene flow across the island's physical and ecological features. To evaluate these models, phylogeographical analyses were conducted on a widespread and endemic species of bat, Myotis goudoti (Vespertilionidae). Location Madagascar.Methods In order to reconstruct the phylogeographical history of M. goudoti, the mitochondrial D-loop and the cytochrome b gene were sequenced for 195 bats from 41 localities. Phylogenetic reconstructions and a minimum spanning tree were used to infer haplotype relationships. The effect of barriers on gene flow was evaluated using analyses of molecular variance and pairwise population differentiation. Mismatch distribution and coalescence-based estimates were conducted to infer the demographic history of M. goudoti. ResultsThe sequenced individuals showed 159 distinct D-loop haplotypes, most of them being unique to a single location. Populations were significantly structured (F ST = 0.170, P < 0.001) across Madagascar, but only a minor part of the overall genetic variance was explained by any of the three models. Shared ancestry of lineages across most physical or ecological barriers was common, whereas the uncovered genetic differences between southern and central-northern populations were unexpected.Main conclusions Major barriers predicted by the three biogeographical models do not explain the segregation of mitochondrial lineages of M. goudoti across Madagascar. This is not simply attributable to the high dispersal ability of this species, as populations are notably structured. The genetic contrast between southern and central-northern populations, separated by a zone of admixture, suggests that these areas currently support populations that expanded during the Late Pleistocene. This latitudinal differentiation of populations has been observed in less vagile animals, such as geckos and lemurs, suggesting that climate fluctuations of the Pleistocene had an impact across several groups and resulted in northern and southern refugia in Madagascar.

Genetically and geographically isolated lineages of a tropical bat (Chiroptera: Molossidae) show demographic stability over the late Pleistocene

“…Interestingly, the control region genetic distances between populations of C. atsinanana are similar to those reported for another species of endemic Malagasy bat, Myotis goudoti (mean 4.2%; maximum 9%; Weyeneth et al ., 2011) and the relatively less mobile Australian ghost bat, Macroderma gigas (Dobson, 1887) (control region divergence up to 6%, 87% of variance among populations; Worthington‐Wilmer et al ., 1994). As is the case for Macroderma gigas , C. atsinanana fits Avise et al .…”

“…Nested clade analysis has revealed some significant latitudinal phylogeographic associations between north versus central and south versus central C. leucogaster haplotype groups (Ratrimomanarivo et al ., 2009), and provides an inference of past fragmentation followed by range expansion. Such latitudinal stratification has also been reported for the widespread endemic Malagasy bat, Myotis goudoti (Weyeneth et al ., 2011). These authors report a zone of admixture between southern and central northern lineages in a broad central band (from 20° to 23°S), located further south than the central C. leucogaster haplotypes (from 15° to 17°S).…”

“…The null model for the effect of glacial changes is concordance in historical demographic and genetic patterns across the two Malagasy Chaerephon species, C. leucogaster and C. atsinanana (Weir & Schluter, 2004). As there is evidence for expansion of populations of C. leucogaster (Ratrimomanarivo et al ., 2009), and of the broadly distributed Malagasy bat, Myotis goudoti (Smith, 1834) (Weyeneth, Goodman & Ruedi, 2011), from Pleistocene refugia, we would expect to find a similar expansion of C. atsinanana . Anticipated genetic signatures of range expansions might include star‐shaped haplotype networks, an excess of singletons, and unimodal mismatch distributions (Excoffier, Foll & Petit, 2009).…”

Resurrection of the island rule – human-driven extinctions have obscured a basic evolutionary pattern

“…Raia et al (2010) also included bats, whereas the classic studies that support the island rule focused on non-flying mammals (Lomolino 1985) or analyzed bats separately (Lomolino 2005). If supported, the island rule is likely a consequence of island isolation, and the substantially lower levels of endemism in bats than in non-flying mammals (Weyeneth et al 2011) indicates that the island bat fauna is less isolated compared to non-flying mammalian fauna. Thus, the island rule would be expected to establish a weaker pattern for bats than for non-bats.…”

An integrative approach to characterize Malagasy bats of the subfamily Vespertilioninae Gray, 1821, with the description of a new species ofHypsugo

“…Most Malagasy bat genera or species complexes have been the subject of phylogenetic and phylogeographic studies. The last taxonomic assemblage of Malagasy bats yet to be treated in the same detailed manner is the subfamily Vespertilioninae, referred to herein as vespers or pipistrelles; exceptions include Myotis goudoti (A. Smith, 1834) (Weyeneth, Goodman & Ruedi, ) and to a lesser extent members of the genus Scotophilus Leach, 1821 (Trujillo et al ., ). Even after the important advances presented in Bates et al .…”