Background. The common vampire bat Desmodus rotundus is an excellent model organism for studying ecological vicariance in the Neotropics due to its broad geographic range and its preference for forested areas as roosting sites. With the objective of testing for Pleistocene ecological vicariance, we sequenced a mitocondrial DNA (mtDNA) marker and two nuclear markers (RAG2 and DRB) to try to understand how Pleistocene glaciations affected the distribution of intraspecific lineages in this bat. Results. Five reciprocally monophyletic clades were evident in the mitochondrial gene tree, and in most cases with high bootstrap support: Central America (CA), Amazon and Cerrado (AMC), Pantanal (PAN), Northern Atlantic Forest (NAF) and Southern Atlantic Forest (SAF). The Atlantic forest clades formed a monophyletic clade with high bootstrap support, creating an east/west division for this species in South America. On the one hand, all coalescent and non-coalescent estimates point to a Pleistocene time of divergence between the clades. On the other hand, the nuclear markers showed extensive sharing of haplotypes between distant localities, a result compatible with male-biased gene flow. In order to test if the disparity between the mitochondrial and nuclear markers was due to the difference in mutation rate and effective size, we performed a coalescent simulation to examine the feasibility that, given the time of separation between the observed lineages, even with a gene flow rate close to zero, there would not be reciprocal monophyly for a neutral nuclear marker. We used the observed values of theta and an estimated mutation rate for the nuclear marker gene to perform 1000 iterations of the simulation. The results of this simulation were inconclusive: the number of iterations with and without reciprocal monophyly of one or more clades are similar. Conclusions. We therefore conclude that the pattern exhibited by the common vampire bat, with marked geographical structure for a mitochondrial marker and no phylogeographic structure for nuclear markers is compatible with a historical scenario of complete isolation of refuge-like populations during the Pleistocene. The results on demographic history on this species is compatible with the Carnaval-Moritz model of Pleistocene vicariance, with demographic expansions in the southern Atlantic forest.
Bibliographical noteFunding Information:
The authors thank the following researchers and/or institutions for collaborating with samples for this study: the Royal Ontario Museum (ROM) and Burton Lim; the American Museum of Natural History (AMNH) and Nancy simmons; Susi Pacheco; Ana Carolina Martins; Caroline Aires; Ives Arnone; Sérgio Althoff; and the agriculture offices of the states of São Paulo, Mato Grosso and Tocantins. We also would like to thank Dr. Fernando Marques for making the simulation analysis using TNT possible by developing the LINUX script; and thank Steven Woolley for assistance with computer-based analyses. Thanks for Adalberto Cesari, Leon Franciatto, Verônica Bueno, Mauro Cardoso Jr. and Paulo Noffs for help with figures. Also thanks for Adalberto Cesari for english revisions. Part of this work was carried out by using the resources of the Computational Biology Service Unit from Cornell University which is partially funded by Microsoft Corporation. We would like to thank two anonymous reviewers for detailed and helpful suggestions. This work became possible through finacial aid from FAPESP grants number 03/01583 -3 and 04/08682-4 and CAPES grant number BEX4687/06-0.
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics