The evolutionary history of bees in time and space.

Bees are the most significant pollinators of flowering plants. This partnership began ca. 120 million years ago, but the uncertainty of how and when bees spread across the planet has greatly obscured investigations of this key mutualism. We present a novel analysis of bee biogeography using extensive new genomic and fossil data to demonstrate that bees originated in Western Gondwana (Africa and South America). Bees likely originated in the Early Cretaceous, shortly before the breakup of Western Gondwana, and the early evolution of any major bee lineage is associated with either the South American or African land masses. Subsequently, bees colonized northern continents via a complex history of vicariance and dispersal. The notable early absences from large landmasses, particularly in Australia and India, have important implications for understanding the assembly of local floras and diverse modes of pollination. How bees spread around the world from their hypothesized Southern Hemisphere origin parallels the histories of numerous flowering plant clades, providing an essential step to studying the evolution of angiosperm pollination syndromes in space and time.

The evolutionary history of the cellophane bee genus Colletes Latreille (Hymenoptera: Colletidae): Molecular phylogeny, biogeography and implications for a global infrageneric classification.

Colletes Latreille (Hymenoptera: Colletidae) is a diverse genus with 518 valid species distributed in all biogeographic realms, except Australasia and Antarctica. Here we provide a comprehensive dated phylogeny for Colletes based on Bayesian and maximum likelihood-based analyses of DNA sequence data of six loci: 28S rDNA, cytochrome c oxidase subunit 1, elongation factor-1α copy F2, long-wavelength rhodopsin, RNA polymerase II and wingless. In total, our multilocus matrix consists of 4824 aligned base pairs for 143 species, including 112 Colletes species plus 31 outgroups (one stenotritid and a diverse array of colletids representing all subfamilies). Overall, analyses of each of the six single-locus datasets resulted in poorly resolved consensus trees with conflicting phylogenetic signal. However, our analyses of the multilocus matrix provided strong support for the monophyly of Colletes and show that it can be subdivided into five major clades. The implications of our phylogenetic results for future attempts at infrageneric classification for the Colletes of the world are discussed. We propose species groups for the Neotropical species of Colletes, the only major biogeographic realm for which no species groups have been proposed to date. Our dating analysis indicated that Colletes diverged from its sister taxon, Hemicotelles Toro and Cabezas, in the early Oligocene and that its extant lineages began diversifying only in the late Oligocene. According to our biogeographic reconstruction, Colletes originated in the Neotropics (most likely within South America) and then spread to the Nearctic very early in its evolutionary history. Geodispersal to the Old World occurred soon after colonization of the Northern Hemisphere. Lastly, the historical biogeography of Colletes is analyzed in light of available geological and palaeoenvironmental data.

Fifteen new species of Liphanthus Reed (Hymenoptera: Andrenidae) with two submarginal cells.

Hitherto, the panurgine genus Liphanthus Reed 1894 has been thought to have only a single species with two, as opposed to three, submarginal cells. Here we describe an additional fifteen species with two submarginal cells. These new species are: L. jenamro Mir Sharifi Packer, L. sapos Mir Sharifi Packer, L. domeykoi Packer, L. discolor Mir Sharifi Packer, L. centralis Mir Sharifi Packer, L. molavi Mir Sharifi Packer (all of the above are from Chile), L. abotorabi Mir Sharifi Packer, L. cochabambensis Mir Sharifi Packer (both from Bolivia), L. fritzi Mir Sharifi Packer, L. amblayensis Mir Sharifi Packer (both from Argentina), L. ancashensis Mir Sharifi Packer (from Peru), L. tregualemensis Packer (from Chile), L. yrigoyeni Packer, L. sparsipunctus Packer (both from Argentina) and L. aliavenus Packer (from Chile). Only L. tregualemensis readily fits within any of the previously described subgenera-Liphanthus (Leptophanthus) Ruz and Toro 1983. Liphanthus aliavenus is known from two specimens, one with three and one with two submarginal cells whereas L. molavi has one individual with two submarginal cells on one forewing and three on the other while all other specimens have two submarginal cells on each forewing. We verified that none of these new species are merely two submarginal celled variants of species with three submarginal cells (such intraspecific variation arises also in some other bees) by i) comparing each of the new species with all keys, figures and descriptions of all Liphanthus species, ii) comparisons with holotypes and/or paratypes of most of the described species and iii) surveys of the specimens of undescribed species with three submarginal cells in our collection. None of the new species seem closely related to L. (Neoliphanthis) bicellularis Ruz and Toro 1983, the only previously described Liphanthus species with two submarginal cells. It is the second submarginal crossvein that is lost in all species except L. aliavenus in which the first submarginal cross vein is lost. DNA barcode data are presented for some of the species. Some interesting morphological features associated with the penis valves are described and discussed. The genus is recorded from Bolivia for the first time.

Fifteen new species of Chilicola (Oroediscelis) (Hymenoptera: Colletidae: Xeromelissinae) with illustrated keys to the males and females of the subgenus.

Fifteen new species of Chilicola subgenus Oroediscelis are described and illustrated. The following 11 species are from Argentina recording a remarkable diversity and the first records of the subgenus in the country: Chilicola capillitas Packer and Dumesh, new species, C. abrebotellas, Packer and Dumesh, new species; C. goloboffi Packer and Dumesh, new species; C. fritzi, Packer and Dumesh, new species; C. rozeni Packer and Dumesh, new species; C. roigi Packer and Dumesh, new species; C. carpenteri Packer Dumesh, new species; C. calchaqui Packer and Dumesh, new species; C. jaguense Packer and Dumesh, new species; C. cuyense Dumesh Packer, new species; and C. huarpe Packer and Dumesh, new species. Chilicola pustulata Packer and Dumesh, new species, and Chilicola luna Dumesh, and Packer new species, are described from Peru; C. boharti Packer and Dumesh, new species, and C. ashei Dumesh and Packer, new species, are described from Bolivia, where C. carpenteri also occurs. An unusual feature of the male antennae is described: long setae on F2 and F3 (less commonly F4) that are appressed to, and occasionally longer than, the succeeding flagellomere. Additional records for previously described species are listed and a revised key to males is provided as well as a provisional complete key for all females.

DNA barcoding the bees (Hymenoptera: Apoidea) of Chile: species discovery in a reasonably well known bee fauna with the description of a new species of Lonchopria (Colletidae).

We compare the diversity of bees in the Chilean fauna as understood from traditional taxonomy-based catalogues with that currently known from DNA barcodes using the BIN system informed by ongoing morphology-based taxonomic research. While DNA barcode surveys of the Chilean bee fauna remain incomplete, it is clear that new species can readily be distinguished using this method and that morphological differentiation of distinct barcode clusters is sometimes very easy. We assess the situation in two genera in some detail. In Lonchopria Vachal one "species" is readily separable into two BINs that are easily differentiated based upon male mandibular and genitalic morphology (characters generally used in this group) as well as female hair patterns. Consequently, we describe Lonchopria (Lonchopria) heberti Packer and Ruz, new species. For Liphanthus Reed, a large number of new species has been detected using DNA barcoding and considerable additional traditional morphological work will be required to describe them. When we add the number of BINs (whether identified to named species or not) to the number of Chilean bee species that we know have not been barcoded (both described and new species under study in our laboratories) we conclude that the bee fauna of Chile is substantially greater than the 436 species currently known. Spanish language abstract available as supplementary data 1 .

DNA barcoding as a useful tool in the systematic study of wild bees of the tribe Augochlorini (Hymenoptera: Halictidae).

Special care is needed in the delimitation and identification of halictid bee species, which are renowned for being morphologically monotonous. Corynura Spinola and Halictillus Moure (Halictidae: Augochlorini) contain species that are key elements in southern South American ecosystems. These bees are very difficult to identify due to close morphological similarity among species and high sexual dimorphism. We analyzed 170 barcode-compliant COI sequences from 19 species. DNA barcodes were useful to confirm gender associations and to detect two new cryptic species. Interspecific distances were significantly higher than those reported for other bees. Maximum intraspecific divergence was less than 1% in 14 species. Barcode index numbers (BINs) were useful to identify putative species that need further study. More than one BIN was assigned to five species. The name Corynura patagonica (Cockerell) probably refers to two cryptic species. The results suggest that Corynura and Halictillus species can be identified using DNA barcodes. The sequences of the species included in this study can be used as a reference to assess the identification of unknown specimens. This study provides additional support for the use of DNA barcodes in bee taxonomy and the identification of specimens, which is particularly relevant in insects of ecological importance such as pollinators.

Revision of the Neotropical subgenera Coelioxys (Platycoelioxys) Mitchell and C. (Rhinocoelioxys) Mitchell (Hymenoptera; Megachilidae) with the description of one new species.

Two Neotropical subgenera of Coelioxys Latreille are revised. The monotypic C. (Platycoelioxys) Mitchell and C. (Rhinocoelioxys) Mitchell has seven valid species; six of them (C. agilis Smith, C. barbata Schwarz & Michener, C. clypearis Friese, C. nasidens Friese, C. paraguayensis Schrottky and C. zapoteca Cresson) previously described, and one, C. platygnatha Rocha-Filho & Packer n. sp. is new from Amazonas State, Brazil. Coelioxys nasidens, previously considered a junior synonym of C. clypeata Smith, is resurrected. Coelioxys crassiceps Friese and C. excisa Friese are synonymized under C. agilis, and C. rostrata Friese is synonymized under C. paraguayensis. Nine names (C. clypeata, C. leucochrysea Cockerell, C. angustivalva Holmberg, C. doelloi Holmberg, C. blabera Holmberg, C. mesopotamica Holmberg, C. bilobata Friese, C. bilobata schenki Friese and C. bullaticeps Friese) are synonymized with C. zapoteca. In the latter species the shape of the apical margin of the clypeus of the female varies widely and, though intermediates occur among all forms, the DNA barcode sequences for the different forms are very similar. One species formerly considered as incertae sedis, C. clypearis, and one belonging to the subgenus C. (Cyrtocoelioxys) Mitchell, C. barbata, are both assigned to the subgenus C. (Rhinocoelioxys). Keys for both sexes of C. (Rhinocoelioxys), distribution maps, host and floral records, redescriptions of species and the description of a new species are provided. In the subgenus C. (Platycoelioxys), only one species, C. alatiformis Friese, is recognized with two junior synonyms: C. crassiceps Friese syn. nov. and C. spatuliventer Cockerell.

Two new species of Geodiscelis Michener & Rozen (Hymenoptera: Apoidea: Colletidae) with a phylogenetic analysis and subgeneric classification of the genus.

Two new species of the genus Geodiscelis are described: Geodiscelis nazcalinea Packer & Dumesh, sp. nov. from Peru (the first record of the genus from that country) and G. phisquiri Packer & Dumesh, sp. nov. from northern Chile. The new species are most closely related to G. longiceps, but differ primarily in having somewhat less elongate heads and in details of the male terminalia. A key to the five known species of the genus is provided as are the results of a phylogenetic analysis based upon 68 characters, and the genus is formally divided into three subgenera: Geodiscelis s. str. Michener and Rozen, Geodiscelis (Nazcoediscelis) Packer and Dumesh, subgenus nov. and Geodiscelis (Thaumoediscelis) Packer and Dumesh, subgenus nov. The two new species described herein belong to subgenus Geodiscelis (Nazcoediscelis). Figures of the most important characters are provided. Tiquilia sp. (Boraginaceae) is the probable floral host of both new species and it is suggested that all species are ground-nesters. Sexual dimorphism in an unusual character is recorded for G. thaumaskelos Packer. 

Three new species of Neofidelia (Hymenoptera: Apoidea: Megachilidae) from Northern Chile.

Neofidelia apacheta Dumesh and Packer, sp. nov., N. camanchaca Dumesh and Packer, sp. nov., and N. submersa Dumesh and Packer, sp. nov. are described from northern Chile. Neofidelia apacheta is known from large numbers of specimens and localities at moderately high elevation (1600-3200m). Neofidelia camanchaca is only known from the ho-lotype male. Neofidelia submersa is known from the holotype male and a pair of paratypes in poor condition, all from a coastal fog oasis. Comparisons are made with the two previously described species of the genus. The collection of N. apa-cheta from so far north in Chile suggests that Neofidelia is likely to be found in southern Peru. A key for the five species of the genus is provided.

Use of diploid male frequency data as an indicator of pollinator decline.

Pollination deficits in agricultural and natural systems are suggestive of large reductions in pollinator populations. However, actual declines are difficult to demonstrate using census data. Here, we show census data to be misleading because many abundant pollinators exhibit high levels of production of sterile diploid males usually found only in small inbred hymenopteran populations; Euglossa imperialis exhibits high levels of diploid male production induced by low effective population sizes (Ne approximately 15), despite being the most abundant orchid bee in lowland tropical forests in Panama. We caution that although some pollinators appear abundant on the basis of census data, their long-term persistence may be highly tenuous based on genetic evidence. We propose the use of diploid male frequency data as a metric for assessing the sustainability of bee populations.