Phylogeny, diversification patterns and historical biogeography of euglossine orchid bees (Hymenoptera: Apidae)

Abstract

The orchid bees constitute a clade of prominent insect pollinators distributed throughout the Neotropical region. Males of all species collect fragrances from natural sources, including flowers, decaying vegetation and fungi, and store them in specialized leg pockets to later expose during courtship display. In addition, orchid bees provide pollination services to a diverse array of Neotropical angiosperms when foraging for food and nesting materials. However, despite their ecological importance, little is known about the evolutionary history of orchid bees. Here, we present a comprehensive molecular phylogenetic analysis based on~4.0 kb of DNA from four loci [cytochrome oxidase (CO1), elongation factor 1-a (EF1-a), arginine kinase (ArgK) and RNA polymerase II (Pol-II)] across the entire tribe Euglossini, including all five genera, eight subgenera and 126 of the approximately 200 known species. We investigated lineage diversification using fossil-calibrated molecular clocks and the evolution of morphological traits using disparity-through-time plots. In addition, we inferred past biogeographical events by implementing model-based likelihood methods. Our dataset supports a new view on generic relationships and indicates that the cleptoparasitic genus Exaerete is sister to the remaining orchid bee genera. Our divergence time estimates indicate that extant orchid bee lineages shared a most recent common ancestor at 27-42 Mya. In addition, our analysis of morphology shows that tongue length and body size experienced rapid disparity bursts that coincide with the origin of diverse genera (Euglossa and Eufriesea). Finally, our analysis of historical biogeography indicates that early diversification episodes shared a history on both sides of Mesoamerica, where orchid bees dispersed across the Caribbean, and through a Panamanian connection, thus reinforcing the hypothesis that recent geological events (e.g. the formation of the isthmus of Panama) contributed to the diversification of the rich Neotropical biota.

Setting the pace of life: membrane composition of flight muscle varies with metabolic rate of hovering orchid bees

“…Both analyses were done using the phylogenetic tree obtained from RNA polymerase II (RNAP II), cytochrome oxidase subunit 1 (CO1), arginine kinase (argK) and elongation factor 1-alpha (EF-1 alpha) gene sequences. To generate the tree, we first compiled the sequences for our 22 species using GenBank based on the analysis found in Ramírez et al [41]. We included two outgroup species in the analysis (Apis cercana and Apis dorsata), as well as Aglae caerulea, the putative ancestral genus at the base of the orchid bee tribe.…”

Revision of the orchid bee subgenus <i>Euglossella</i> (Hymenoptera: Apidae), part II: The <i>viridis</i> and <i>mandibularis</i> species groups

“…Whereas Dressler (1978) had included a single species group in Euglossella (the viridis group), Hinojosa-Díaz & Engel (2011a) divided it into two groups (the viridis and decorata groups), based mainly on differences in integumental coloration. Phylogenetic evidence provided by data from morphology (Hinojosa-Díaz, 2010) and DNA sequences (Ramírez et al, 2010) set the basis for the proposal of a third species group (the mandibularis group), which is presented here. The viridis and mandibularis groups are revised here, and an updated and expanded key to all species groups in the subgenus is provided.…”

The Ecological Basis for Biogeographic Classification: an Example in Orchid Bees (Apidae: Euglossini)

“…The distribution of bees is frequently analyzed according to distinct regional or vegetation terms that are otherwise difficult to define (Roubik & Hanson 2004), and few empirical studies on the geographic distribution of euglossines have been performed (Dick et al 2004, Nemésio 2007b, Ramírez et al 2010.…”

“…It is commonly assumed that orchid bees originated between the Andean foothills and the Amazon region more than 20 my ago with a significant radiation of the group occurred in the Miocene/Pleistocene (Engel 1999, Dick et al 2004, Roubik and Hanson 2004. Recent evidence suggests that euglossines date from the Eocene and that it is not necessarily clear that they originated in South America (Ramírez et al 2010). The current distribution of euglossine bees should reflect geological, environmental, and climatic factors in addition to the occurrence of resource competition, parasites and predators (Nemésio & Silveira 2006, Roubik & Hanson 2004.…”

“…Given the relatively recent and widespread distribution of orchid bees (Dick et al 2004), the ancestors of the group should occur at the time of the uplift of the Andean cordillera and at a level of uplift that reached no greater than 40% of the current altitude of the cordillera (Ramírez et al 2010). Bee community structures did not appear in association with the uplift (Gregory-Wodzicki 2000, Dick et al 2004, Michener 2007.…”