Intraspecific Geographic Variation of Fragrances Acquired by Orchid Bees in Native and Introduced Populations

Male orchid bees collect volatiles, from both floral and non-floral sources, that they expose as pheromone analogues (perfumes) during courtship display. The chemical profile of these perfumes, which includes terpenes and aromatic compounds, is both species-specific and divergent among closely related lineages. Thus, fragrance composition is thought to play an important role in prezygotic reproductive isolation in euglossine bees. However, because orchid bees acquire fragrances entirely from exogenous sources, the chemical composition of male perfumes is prone to variation due to environmental heterogeneity across habitats. We used Gas Chromatography/Mass Spectrometry (GC/MS) to characterize the perfumes of 114 individuals of the green orchid bee (Euglossa aff. viridissima) sampled from five native populations in Mesoamerica and two naturalized populations in the southeastern United States. We recorded a total of 292 fragrance compounds from hind-leg extracts, and found that overall perfume composition was different for each population. We detected a pronounced chemical dissimilarity between native (Mesoamerica) and naturalized (U.S.) populations that was driven both by proportional differences of common compounds as well as the presence of a few chemicals unique to each population group. Despite these differences, our data also revealed remarkable qualitative consistency in the presence of several major fragrance compounds across distant populations from dissimilar habitats. In addition, we demonstrate that naturalized bees are attracted to and collect large quantities of triclopyr 2-butoxyethyl ester, the active ingredient of several commercially available herbicides. By comparing incidence values and consistency indices across populations, we identify putative functional compounds that may play an important role in courtship signaling in this species of orchid bee

Figure 7 in Characterization of the orchid bee Euglossa viridissima (Apidae: Euglossini) and a novel cryptic sibling species, by morphological, chemical, and genetic characters

Figure 7. Geographical distribution of tridentate Euglossa dilemma sp. nov. (black) and predominantly bidentate Euglossa viridissima (white) as inferred from recent baiting assays (circles) as well as museum material (diamonds). Note lack of E. viridissima in the south-eastern part (Costa Rica) of the range. Museum material included paratypes of E. dilemma and additional specimens of one or both species in the collections of D. W. Roubik, T. Eltz (CTE), G. Gerlach (CGG), the Zoologische Staatssammlung München (ZSM), the Smithsonian Institution (SI), and the Snow Entomological Collection (SEC). Only unambiguous and non-redundant localities were plotted. Localities of baiting assays are (from west to east): Chamela (Jalisco, Mexico), El Chote (Veracruz, Mexico), Ayozinthepec (Oaxaca, Mexico), Monte Pio and Poza Azul (both Veracruz, Mexico), Tuxtla Gutiérrez, Esquintla, Tapachula, Ocosingo and Palenque (all Chiapas, Mexico), Atasta (Campeche, Mexico), Retalhuleu (Guatemala), Lacanjá (Chiapas, Mexico), Escarcega (Campeche, Mexico), El Remate (Campeche, Mexico), Chablekal, Xmatkuil (Yucatán, Mexico), Tikal (Guatemala), San Crisanto (Yucatán, Mexico), Chetumal and Coba (both Quintana Roo, Mexico), Chinandega, Chacocente, Escameca Grande, Jinotega, Ometepe and Las Pampas (all Nicaragua), and Area de Conservación Guanacaste (Costa Rica).Published as part of <i>Eltz, Thomas, Fritzsch, Falko, Pech, Jorge Ramírez, Zimmermann, Yvonne, Ramírez, Santiago R., Quezada-Euan, J. Javier G. & Bembé, Benjamin, 2011, Characterization of the orchid bee Euglossa viridissima (Apidae: Euglossini) and a novel cryptic sibling species, by morphological, chemical, and genetic characters, pp. 1064-1076 in Zoological Journal of the Linnean Society 163 (4)</i> on page 1074, DOI: 10.1111/j.1096-3642.2011.00740.x, <a href="http://zenodo.org/record/10114764">http://zenodo.org/record/10114764</a&gt

Figure 6 in Characterization of the orchid bee Euglossa viridissima (Apidae: Euglossini) and a novel cryptic sibling species, by morphological, chemical, and genetic characters

Figure 6. Chronogram showing divergence times and phylogenetic relationships of selected lineages in the genus Euglossa and the sibling species Euglossa dilemma sp. nov. and E. viridissima. The tree topology corresponds to that obtained via Bayesian methods. Bayesian posterior probabilities and parsimony bootstrap values are shown for the sister species only. Divergence times were obtained via penalized likelihood using the fossil-calibrated molecular clock procedures described in Ramírez et al. (2010b). The maximum and minimum age estimates for the MRCA of E. dilemma and E. viridissima correspond to the molecular clock analyses in which the MRCA of the genus Euglossa was assigned a fossil calibration of 20 and 15 Myr, respectively.Published as part of <i>Eltz, Thomas, Fritzsch, Falko, Pech, Jorge Ramírez, Zimmermann, Yvonne, Ramírez, Santiago R., Quezada-Euan, J. Javier G. & Bembé, Benjamin, 2011, Characterization of the orchid bee Euglossa viridissima (Apidae: Euglossini) and a novel cryptic sibling species, by morphological, chemical, and genetic characters, pp. 1064-1076 in Zoological Journal of the Linnean Society 163 (4)</i> on page 1073, DOI: 10.1111/j.1096-3642.2011.00740.x, <a href="http://zenodo.org/record/10114764">http://zenodo.org/record/10114764</a&gt

Figure 4 in Characterization of the orchid bee Euglossa viridissima (Apidae: Euglossini) and a novel cryptic sibling species, by morphological, chemical, and genetic characters

Figure 4. Results of a PCA of 15 morphological variables measured in male Euglossa viridissima and Euglossa dilemma sp. nov. Components 1 and 3, which showed significant differences between the species, are used for this two-dimensional representation. Note that E. dilemma shows slightly less variability and is essentially nested within E. viridissima morphospace. Centroids of distributions are shown.Published as part of <i>Eltz, Thomas, Fritzsch, Falko, Pech, Jorge Ramírez, Zimmermann, Yvonne, Ramírez, Santiago R., Quezada-Euan, J. Javier G. & Bembé, Benjamin, 2011, Characterization of the orchid bee Euglossa viridissima (Apidae: Euglossini) and a novel cryptic sibling species, by morphological, chemical, and genetic characters, pp. 1064-1076 in Zoological Journal of the Linnean Society 163 (4)</i> on page 1070, DOI: 10.1111/j.1096-3642.2011.00740.x, <a href="http://zenodo.org/record/10114764">http://zenodo.org/record/10114764</a&gt

Figure 1 in Characterization of the orchid bee Euglossa viridissima (Apidae: Euglossini) and a novel cryptic sibling species, by morphological, chemical, and genetic characters

Figure 1. Differences in the chemical composition of tibial perfumes between tridentate (black circles) and bidentate (grey circles) Euglossa viridissima-like males as revealed by a multidimensional scaling (MDS) analysis. Only tridentate males contained HNDB. Tridentate males without HNDB are highlighted (red symbols).Published as part of <i>Eltz, Thomas, Fritzsch, Falko, Pech, Jorge Ramírez, Zimmermann, Yvonne, Ramírez, Santiago R., Quezada-Euan, J. Javier G. & Bembé, Benjamin, 2011, Characterization of the orchid bee Euglossa viridissima (Apidae: Euglossini) and a novel cryptic sibling species, by morphological, chemical, and genetic characters, pp. 1064-1076 in Zoological Journal of the Linnean Society 163 (4)</i> on page 1067, DOI: 10.1111/j.1096-3642.2011.00740.x, <a href="http://zenodo.org/record/10114764">http://zenodo.org/record/10114764</a&gt

Figure 2 in Characterization of the orchid bee Euglossa viridissima (Apidae: Euglossini) and a novel cryptic sibling species, by morphological, chemical, and genetic characters

Figure 2. Allele size distribution of Euglossa viridissima- like males from the Yucatán peninsula, Mexico, at the microsatellite locus ann02. Overall, bidentate males (grey bars) had significantly smaller allele sizes than tridentate individuals (black bars), and there was little overlap in allele size. The seven individuals indicated as red circles were also tridentate, but had been clustered with bidentate males in the analysis of perfume similarity (see Fig. 1), lacking HNDB. These seven individuals had the third (central) mandibular tooth significantly displaced towards the tip of the mandible (nearer to the distal tooth, see Fig. 3B), unlike in other tridentate males. Their ann02 allele size suggests that they in fact belong to the bidentate lineage. See text for further explanation.Published as part of <i>Eltz, Thomas, Fritzsch, Falko, Pech, Jorge Ramírez, Zimmermann, Yvonne, Ramírez, Santiago R., Quezada-Euan, J. Javier G. & Bembé, Benjamin, 2011, Characterization of the orchid bee Euglossa viridissima (Apidae: Euglossini) and a novel cryptic sibling species, by morphological, chemical, and genetic characters, pp. 1064-1076 in Zoological Journal of the Linnean Society 163 (4)</i> on page 1068, DOI: 10.1111/j.1096-3642.2011.00740.x, <a href="http://zenodo.org/record/10114764">http://zenodo.org/record/10114764</a&gt