Climate change is shifting the environmental cues that determine the phenology of interacting species. Plant-pollinator systems may be susceptible to temporal mismatch if bees and flowering plants differ in their phenological responses to warming temperatures. While the cues that trigger flowering are well-understood, little is known about what determines bee phenology. Using generalised additive models, we analyzed time-series data representing 67 bee species collected over 9 years in the Colorado Rocky Mountains to perform the first community-wide quantification of the drivers of bee phenology. Bee emergence was sensitive to climatic variation, advancing with earlier snowmelt timing, whereas later phenophases were best explained by functional traits including overwintering stage and nest location. Comparison of these findings to a long-term flower study showed that bee phenology is less sensitive than flower phenology to climatic variation, indicating potential for reduced synchrony of flowers and pollinators under climate change.

The state of Michigan occupies an area between the Great Plains and the northeastern United States, bordering four Great Lakes, with diverse biogeographical regions. Michigan also has the second most diverse agriculture in the country, with many crops that depend on bees for pollination. This unique combination provides a wide range of opportunities for bees to persist, yet there is no current published checklist of these important insects. This study was conducted to provide the first annotated checklist of the bee (Apoidea: Anthophila) fauna of Michigan, summarizing aspects of their taxonomy and behavior and to provide provisional conservation assessment. The list was compiled from a critical review of published literature, museum specimens, and database records, supplemented by new collections. In total, 465 species are included in the checklist, including 38 new records, however evidence for 13 species is poor, several more species require taxonomic revision, and the presence of additional species is expected. The exotic megachilid species Megachile apicalis Spinola, M. pusilla Pérez (=concinna Smith, auct.) and Osmia taurus Smith are reported from Michigan for the first time. New state records of native species include Anthidium tenuiflorae Cockerell and Nomada alpha alpha Cockerell, both previously undocumented from eastern North America, and Nomada sphaerogaster Cockerell, which has rarely been recognized. The taxonomy of some bee species is clarified by the formal publication of 11 new synonymies (some previously reported online or in manuscripts). The following list cites junior synonyms first followed by the valid name: Andrena chippewaensis Mitchell 1960 = A. (Simandrena) wheeleri Graenicher 1904; Osmia hendersoni Cockerell 1907 = O. (Melanosmia) tarsata Provancher 1888; Osmia michiganensis Mitchell 1962 = O. (M.) subarctica Cockerell 1912 (new status, removed from synonymy with O. (M.) tersula Cockerell 1912); Sphecodes persimilis Lovell and Cockerell 1907 = S. davisii Robertson 1897; Sphecodes knetschi Cockerell 1898 = S. dichrous Smith 1853; Sphecodes carolinus Mitchell 1956 = S. coronus Mitchell 1956; Sphecodes stygius Robertson 1893 = S. mandibularis Cresson 1872; Sphecodes prostygius Mitchell 1960 = S. fattigi Mitchell 1956; Stelis vernalis Mitchell 1962 = S. coarctatus Crawford 1916; and Stelis michiganensis Mitchell 1962 = S. foederalis Smith 1854. Poorly known Andrena (Cnemidandrena) are discussed, including A. parnassiae Cockerell, a new state record, A. robervalensis Mitchell, and the extralimital A. runcinatae Cockerell. Of these, only A. robervalensis was considered in the subgeneric revision, but we recognize all three as valid species pending further study. Nomada binotata (Robertson 1903) and N. quadrimaculata (Robertson 1903) are removed from synonymy with N. ovata (Robertson 1903), based on examination of the lectotypes. A new species, Triepeolus eliseae Rightmyer, the eastern representative of the verbesinae species group, is described. A putative undescribed species, Osmia aff. trev...

The cleptoparasitic bee genus Triepeolus is a widespread, species-rich group that has never been revised throughout its geographic range. Herein I review 103 species of Triepeolus, including all but those that belong to the newly defined Triepeolus verbesinae and Triepeolus simplex species groups (these will be the topic of a subsequent paper). I present three keys to the species, which together cover the genus throughout its range in the New World; the keys are to the females of North and Central America, the males and females from Eastern North America, and the males and females from South America and the Caribbean. I propose the following 37 new species: Triepeolus antiochensis, T. argentimus, T. argus, T. bimorulus, T. charlesi, T. circumculus, T. claytoni, T. cruciformis, T. diffusus, T. dilutus, T. edwardi, T. engeli, T. exilicurvus, T. flavigradus, T. fulgidus, T. griswoldi, T. interruptus, T. isohedrus, T. jennieae, T. joliae, T. lateralis, T. margaretae, T. mauropygus, T. melanarius, T. micheneri, T. nayaritensis, T. parkeri, T. partitus, T. parvidiversipes, T. parvus, T. perpictus, T. phaeopygus, T. punctoclypeus, T. quadratus, T. simulatus, T. vernus, and T. warriti, and propose the new combinations Triepeolus laticeps (Friese), Triepeolus tepanecus (Cresson) and Triepeolus zacatecus (Cresson). I newly synonymize 45 of the 169 previously proposed Triepeolus names, for a total of 51 synonymies: T. alachuensis Mitchell under T. rufithorax Graenicher; Epeolus albopictus Cockerell, E. costaricensis Friese, and E. flavocinctus Friese under T. aztecus (Cresson); T. alpestris Cockerell, T. amandus Cockerell, and T. vandykei Cockerell and Sandhouse under T. paenepectoralis Viereck; E. bardus Cresson, T. mesillae Cockerell, and T. pimarum Cockerell under T. distinctus (Cresson); T. brunneus Cockerell under T. balteatus Cockerell; T. charlottensis Mitchell under T. brittaini Cockerell; T. cirsianus Mitchell under T. donatus (Smith); T. concinnus Cockerell under T. townsendi Cockerell; T. coquilletti Cockerell, T. helianthi arizonensis Cockerell, T. helianthi pacificus Cockerell, T. lineatulus Cockerell and Sandhouse, and T. maculiventris Cockerell under T. helianthi (Robertson); T. dichropus Cockerell, T. eldredi Cockerell, T. helianthi grandior Cockerell, T. pallidiventris Cockerell and Sandhouse, T. rectangularis Cockerell, and T. wyomingensis Cockerell under T. texanus (Cresson); T. digueti Cockerell and E. nobilis Friese under T. intrepidus (Smith); T. floridanus Mitchellunder T. georgicus Mitchell; T. fortis Cockerell, T. insolitus Cockerell, and T. trilobatus Cockerell under T. martini (Cockerell); T. foxii Cockerell under T. rufoclypeus (Fox); T. lestes Cockerell under T. subalpinus Cockerell; T. loganensis Cockerell and T. sandhousae Cockerell under T. fraserae Cockerell; T. nautlanus Cockerell under T. lunatus (Say); E. nigriceps Smith under T. robustus (Cresson); E. oswegoensis Mitchell under T. pectoralis (Robertson); T. perelegans Cockerell and T. trichopygus Cockerell and Timberlake under T. penicilliferus (Brues); T. signatus Hedicke under T. ventralis (Meade-Waldo); T. stricklandi Cockerell under T. subalpinus Cockerell; E. superbus Provancher and E. texanus nigripes Cockerell under T. remigatus (Fabricius); and E. utahensis Cockerell under T. heterurus (Cockerell and Sandhouse).

A generic-level cladistic analysis of the cleptoparasitic bee tribe Epeolini (Apinae: Nomadinae) is presented. One hundred and two characters of adult external morphology are identified and coded for 32 representatives of all genera and subgenera presently recognized within the tribe, along with five outgroup taxa. The resulting topology is used in the formation of a higher-level classification of the tribe. Four subtribes are characterized: Odyneropsina Handlirsch, Rhogepeolina new subtribe, Epeolina Robertson, and Thalestriina new subtribe. Pscudcpcoliis and Triepeolus are not supported as subgenera of Doeriiigielln and are elevated to generic rank. The subgenus Twphocleptrin renders Epeolus sensu stricto paraphyletic and is svnonymized. The group Paraniiiiobntcs is recognized as a subgenus of Odi/iiewpjsis. Triepeolus epeolurus new species (type locality, Michoacan, Mexico), is described and figured; it is remarkable for a number of autapomorphic traits, particularly those of the pseudopygidial area. A kev to the genera of the tribe is provided. The taxonomic history of the tribe, as well as available information on hosts and biology of epeolines, is summarized. A review of pertinent morphological terminology is presented, with special emphasis on the sting apparatus.