The population genetics of two orchid bees suggests high dispersal, low diploid male production and only an effect of island isolation in lowering genetic diversity
- 772 Downloads
Orchid bees (Hymenoptera, Apidae, Euglossini) are important pollinators of many plant families in Neotropical forests, habitats that have become increasingly degraded and fragmented by agricultural practices. To understand the extent to which loss of natural habitat and isolation has affected the genetic diversity and diploid male production (DMP) of two orchid bee species, Euglossa dilemma and Euglossa viridissima, we collected and genotyped 1686 males at five microsatellite loci and tested for differences in allelic richness, heterozygosity and DMP across three different types of land use (natural, agricultural and urban) and between mainland and island populations in the Yucatan Peninsula of Mexico. We also investigated the impact of land use and geographic isolation on gene flow. Euglossa dilemma and E. viridissima seemed to be particularly resilient to loss of natural habitat; in locations with human impact, we did not find reduced genetic diversity, and populations generally showed very little population genetic structure. Only on islands did E. dilemma show significantly reduced genetic diversity. Even after accounting for putative null alleles, DMP was very low (0.2–1.3%) across all sampling sites, including on islands. We therefore suggest that DMP is an insensitive measure of inbreeding and population decline in our two study species.
KeywordsEffective population size Euglossa Gene flow Habitat fragmentation Inbreeding Mexico Yucatan Peninsula
We thank the editors and referees for comments that helped improve the manuscript, Ramirez Pech, Rubén Medina and Tony Gonzalez for collecting the male individuals used in this study and Petra Leibe and Rita Radzeviciute for their assistance in the laboratory. We thank CONACyT-EU Project FONCICyT 94293 (Mutualismos y abejas en paisajes tropicales) for funding.
- Anonymous (2010) http://comey.yucatan.gob.mx/marco_files/II.6_Desarrollo_urbano_y_OT.pdf.
- Cincotta RP, Engelman R (2000) Nature’s place: human population and the future of biological diversity. Population Action International, Washington, DCGoogle Scholar
- Coulon A, Fitzpatrick JW, Bowman R, Stith BM, Makarewich CA, Stenzler LM, Lovette IJ (2008) Congruent population structure inferred from dispersal behaviour and intensive genetic surveys of the threatened Florida scrub-jay (Aphelocoma cœrulescens). Mol Ecol 17:1685–1701. doi: 10.1111/j.1365-294X.2008.03705.x PubMedCrossRefGoogle Scholar
- Crozier RH, Pamilo P (1996) Evolution of social insect colonies. Sex allocation and Kin selection. Oxford University Press, OxfordGoogle Scholar
- Eltz T, Fritzsch F, Pech JR, Zimmermann Y, RamÍRez SR, Quezada-Euan JJG, BembÉ B (2011) Characterization of the orchid bee Euglossa viridissima (Apidae: Euglossini) and a novel cryptic sibling species, by morphological, chemical, and genetic characters. Zool J Linn Soc 163:1064–1076. doi: 10.1111/j.1096-3642.2011.00740.x CrossRefGoogle Scholar
- Gilpin ME, Soulé ME (1986) Minimum viable populations: process of species extinction. In: Soulé ME (ed) Conservation biology: the science of scarcity and diversity. Sinauer, Sunderland, pp 19–34Google Scholar
- Husemann M, Cousseau L, Callens T, Matthysen E, Vangestel C, Hallmann C, Lens L (2015) Post-fragmentation population structure in a cooperative breeding Afrotropical cloud forest bird: emergence of a source-sink population network. Mol Ecol 24:1172–1187. doi: 10.1111/mec.13105 PubMedCrossRefGoogle Scholar
- Landaverde-González P, Enríquez E, Ariza MA, Murray T, Paxton RJ, Husemann M (2016) Habitat fragmentation and the population genetics of the native bee species Partamona bilineata (Hymenoptera: Apidae: Meliponini) in the cloud forest of Guatemala. In review, this special issueGoogle Scholar
- Lechner S, Ferretti L, Schöning C, Kinuthia W, Willemsen D, Hasselmann M (2014) Nucleotide variability at its limit? Insights into the number and evolutionary dynamics of the sex-determining specificities of the honey bee Apis mellifera. Mol Biol Evol 31:272–287. doi: 10.1093/molbev/mst207 PubMedCrossRefGoogle Scholar
- Maebe K, Meeus I, Ganne M, De Meulemeester T, Biesmeijer K, Smagghe G (2015) Microsatellite analysis of museum specimens reveals historical differences in genetic diversity between declining and more stable Bombus species. PLoS ONE 10:e0127870. doi: 10.1371/journal.pone.0127870 PubMedPubMedCentralCrossRefGoogle Scholar
- Nei M (1987) Molecular evolutionary genetics. Columbia University Press, New YorkGoogle Scholar
- Roubik DW, Hanson PE (2004) Orchid bees of tropical America. Instituto Nacional de Biodiversidad, Costa RicaGoogle Scholar
- Suni SS (2016) Population genetics of Euglossa imperialis reveals low genetic diversity and restricted dispersal over a fragmented area. In review, this special issueGoogle Scholar