Determining the plant-pollinator network in a culturally significant food and medicine garden in the Great Lakes region.

Understanding the interactions between plants and pollinators within a system can provide information about pollination requirements and the degree to which species contribute to floral reproductive success. Past research has focused largely on interactions within monocultured agricultural systems and only somewhat on wild pollination networks. This study focuses on the culturally significant Three Sisters Garden, which has been grown and tended by many Indigenous peoples for generations in the Great Lakes Region. Here, the plant-pollinator network of the traditional Three Sisters Garden with the inclusion of some additional culturally significant plants was mapped. Important visitors in this system included the common eastern bumble bee, Bombus impatiens Cresson (Hymenoptera: Apidae), and the hoary squash bee, Xenoglossa pruinosa (Say) (Hymenoptera: Apidae), as determined by their abundances and pollinator service index (PSI) values. Understanding the key pollinators in the Three Sisters Garden links biological diversity to cultural diversity through the pollination of culturally significant plants. Further, this information could be of use in supporting Indigenous food sovereignty by providing knowledge about which wild pollinators could be supported to increase fruit and seed set within the Three Sisters Garden. Our findings can also lead to more effective conservation of important wild pollinator species.

Establishment of the non-native horned-face bee Osmia cornifrons and the taurus mason bee Osmia taurus (Hymenoptera: Megachilidae) in Canada.

Established populations of the non-native horned-face bee, Osmia cornifrons (Radoszkowski, 1887), and the taurus mason bee, Osmia taurus Smith, 1873 (Hymenoptera: Megachilidae), have been identified from Canada for the first time. In the US, the importation of O. cornifrons, beginning in the 1970s, led to its release for agricultural crop pollination and spread across the country. In this article, we report on O. cornifrons captured while sampling wild bees in Toronto, Ontario using hand nets, bug vacuums, and vane traps, as well as established populations in trap nests, from 2017-2020. The morphologically similar O. taurus, which was accidentally introduced to the US with shipments of imported O. cornifrons, was also recorded in our samples. Recently, a few individual O. taurus specimens have been identified from Ontario and Quebec; however, the extent of our sampling included nests, indicating it is also established in Canada. Others have shown its population growth to have been associated with concordant declines in abundances of native mason bee species in the US, and similar impacts are possible in Canada if action is not taken. We propose three non-mutually exclusive possible pathways for the arrival of O. cornifrons, as well as O. taurus, in Canada: (1) natural migration northward from non-native populations in the US, (2) international importation in the 1980s-2000s to support agricultural research programs, and (3) unintentional release of mason bee cocoons purchased from non-local vendors. We argue that a focus on enhancing populations of locally occurring native bees and stronger policy on the importation and sale of non-native bees are needed.

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.

Phylogeny and biogeography of the cleptoparasitic bee genus Epeolus (Hymenoptera: Apidae) and cophylogenetic analysis with its host bee genus Colletes (Hymenoptera: Colletidae).

The bee genus Epeolus Latreille (Hymenoptera: Apidae) consists of 109 species, which are known to be exclusively cleptoparasites of polyester (or cellophane) bees of the genus Colletes Latreille (Hymenoptera: Colletidae). Both genera have a nearly cosmopolitan distribution and are represented on all continents except Antarctica and Australia. We present the most comprehensive phylogeny for Epeolus to date, based on combined molecular and morphological data. In total, 59 ingroup taxa (species of Epeolus) and 7 outgroup taxa (other Epeolini) were scored for 99 morphological characters, and sequence data were obtained for seven genes (one mitochondrial and six nuclear, 5399 bp in total). Epeolus was found to be monophyletic, with a crown age estimated to be 25.0-13.4 Ma (95% HPD) and its origins traced to the Nearctic region. Epeolus was found to contain six major clades, five of which were well supported. The evolutionary history of Epeolus is explored in the context of earth history events and the evolutionary history of its host genus Colletes, for which a molecular phylogeny was constructed based on the same seven genes. A comparison of Epeolus and Colletes phylogenies limited to taxa for which there is evidence of an association suggests there was some cospeciation. However, more cladogenetic events in Epeolus were linked to instances of dispersal/vicariance. It is not yet clear the extent to which allopatric speciation contributed to diversification in Colletes, but the genus' success in having colonized and diversified across much of the globe made it possible for Epeolus to do the same.

A revision of the cleptoparasitic bee genus Epeolus Latreille for Nearctic species, north of Mexico (Hymenoptera, Apidae).

Herein, the cleptoparasitic (cuckoo) bee genus Epeolus (Hymenoptera: Apidae) is revised for species occurring in North America, north of Mexico, and an updated checklist of all species known to occur in Canada and the United States of America is provided with comprehensive descriptions, diagnoses, and a single dichotomous key (using the same couplets for both sexes) to aid in their identification. To increase their recognition among North American naturalists, English common names are also proposed for all North American Epeolus. A total of 43 species is confirmed as present in the region, 15 of which are newly recognized. The following new species are proposed based on unique morphological (and in most cases also molecular) attributes: E. andriyisp. n., E. attenboroughisp. n., E. axillarissp. n., E. basilisp. n., E. brumleyisp. n., E. chamaesarachaesp. n., E. deyrupisp. n., E. diadematussp. n., E. ferrariisp. n., E. gibbsisp. n., E. inornatussp. n., E. nebulosussp. n., E. packerisp. n., E. splendidussp. n., and E. tessierissp. n. Of the 15, six (E. axillaris, E. brumleyi, E. chamaesarachae, E. diadematus, E. splendidus, and E. tessieris) were identified as new species under different names (nomina nuda) in an M.Sc. thesis by Richard L. Brumley in 1965, but until now they have not been formally described. Detailed morphological comparisons with some evidence from DNA barcoding support the following synonymies, one of which C was first proposed by Brumley (1965): a) E. melectimimus Cockerell and Sandhouse, syn. n., under E. asperatus Cockerell; b) E. crucis Cockerell, syn. n., under E. compactus Cresson; c) E. mesillae palmarum Linsley, syn. n., under E. mesillae (Cockerell); and d) E. weemsi Mitchell, syn. n., and e) E. vernalis Mitchell, syn. n., under E. ilicis Mitchell. Only one member of the almost entirely Neotropical "Trophocleptria group" (Epeolus bifasciatus Cresson) is confirmed as occurring north of Mexico, and is widespread East of the Rocky Mountains. Known floral associations are indicated for each species, as are suspected or known host species of Colletes Latreille. Evidence is presented that suggests further investigation into the possible synonymy of Colletes wickhami Timberlake under C. scopiventer Swenk is warranted.

Honey bees are the dominant diurnal pollinator of native milkweed in a large urban park.

In eastern North America, the field milkweed, Asclepias syriaca L. (Asclepiadaceae), is used in planting schemes to promote biodiversity conservation for numerous insects including the endangered monarch butterfly, Danaus plexippus (Linnaeus) (Nymphalidae). Less is known about its pollinators, and especially in urban habitats where it is planted often despite being under increasing pressure from invasive plant species, such as the related milkweed, the dog-strangling vine (DSV), Vincetoxicum rossicum (Kleopow) Barbar. (Asclepiadaceae). During the A. syriaca flowering period in July 2016, we surveyed bees in open habitats along a DSV invasion gradient and inspected 433 individuals of 25 bee species in 12 genera for pollinia: these were affixed to bees that visited A. syriaca for nectar and contain pollen packets that are vectored (e.g., transferred) between flowers. Of all bees sampled, pollinia were found only on the nonindigenous honeybee, Apis mellifera (43% of all bees identified), as well as one individual bumblebee, Bombus impatiens Cresson. Pollinia were recorded from 45.2% of all honeybees collected. We found no relationship between biomass of DSV and biomass of A. syriaca per site. There was a significant positive correlation between A. syriaca biomass and the number of pollinia, and the proportion vectored. No relationship with DSV biomass was detected for the number of pollinia collected by bees but the proportion of vectored pollinia declined with increasing DSV biomass. Although we find no evidence of DSV flowers attracting potential pollinators away from A. syriaca and other flowering plants, the impacts on native plant-pollinator mutualisms relate to its ability to outcompete native plants. As wild bees do not appear to visit DSV flowers, it could be altering the landscape to one which honeybees are more tolerant than native wild bees.