Conservation Genetics

, Volume 13, Issue 2, pp 323–332 | Cite as

Population genetics of orchid bees in a fragmented tropical landscape

  • Sevan S. SuniEmail author
  • Berry J. Brosi
Research Article


The prospects for persistence of bees living in fragmented landscapes is a topic of considerable interest due to bees’ importance as pollinators of agricultural crops and wild plants, coupled with the ubiquity of native habitat loss and evidence that bees may be declining worldwide. Population persistence in fragmented areas depends on dispersal potential and maintenance of gene flow among fragments of habitat. Here we used population genetic techniques to characterize, for two equally abundant orchid bee species that differ in their physiology and ecology, levels of genetic differentiation among fragments of tropical forest in southeastern Costa Rica in a ~200 km2 landscape. We measured population differentiation with ϕPT (an analogue to the traditional summary statistic Fst), as well as two measures that may more accurately reflect the level of differentiation when highly variable loci are used: G’st and Dest. We also calculated pairwise genetic distances among individuals and conducted Mantel tests to test the correlation of genetic and geographic distance, for each species. We found strong differences in genetic structure between the species. Contrary to our expectations, each measure of genetic structure revealed that the larger-bodied species, Eulaema bombiformis, had higher levels of differentiation than the smaller species, Euglossa championi. Furthermore, for Eulaema bombiformis there was a significant positive correlation of genetic and geographic distance while for Euglossa championi there was no significant positive correlation. Our results demonstrate that bee species can have strikingly different levels of gene flow in fragmented habitats, and that body size may not always act as a useful proxy for dispersal, even in closely related taxa.


Orchid bee Euglossine Genetic differentiation Landscape Dispersal Fragmentation 



We thank the staff at the Las Cruces Biological Station near San Vito, Costa Rica, J. Van Cleve and J. Lyons for helpful comments, M. Kaplan and the staff of University of Arizona’s genomics core facility for help with laboratory work, and T. Brookhart for fieldwork and cartographic assistance. SSS was supported by the Center for Insect Science at the University of Arizona (NIH grant 5 K12 GM000708). Original collection of the bee specimens by BJB was supported by grants to the Center for Conservation Biology at Stanford University from the Koret, McDonnell, Sherwood, and Winslow Foundations and Peter and Helen Bing. Additional fieldwork in Costa Rica by BJB was supported by the Woodruff Travel Fund of Emory University.


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Copyright information

© Springer Science+Business Media B.V. 2011

Authors and Affiliations

  1. 1.Center for Insect ScienceUniversity of ArizonaTucsonUSA
  2. 2.Department of Environmental StudiesEmory UniversityAtlantaUSA

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