AnthWest, occurrence records for wool carder bees of the genus Anthidium (Hymenoptera: Megachilidae, Anthidiini) in the Western Hemisphere

Study Extent

Because this dataset was developed as part of research that was focused on taxonomic revisionary work, sampling was not the focus of efforts; rather the data represents the aggregate of what we know about the distribution and behavior of Anthidium from existing material. Carder bees are diurnal, and are only active when temperatures are well above freezing and only during the growing season when floral resources are potentially available.

Sampling

Specimen records captured in AnthWest are the result of: 1) non-systematic collections usually as part of general entomological collecting events or ones focused on bees in general; 2) standardized biodiversity surveys conducted by the USDA Pollinating Insects Research Unit using a combination of net and pan traps; 3) trap nest studies; and 4) specimens resulting from studies on pollination and reproductive biology of threatened or endangered plants.

Quality Control

All individual specimens included in this dataset were examined during the course of the taxonomic revision using distribution maps and raw data following standardized protocols (Figs. 7, 8). Records with questionable data on original insect labels were included in the dataset but distinguishable by notes in the DWC field “Identification Qualifier”. These records were excluded from published distribution maps in the species-level revision of the genus (Gonzalez and Griswold 2013). A small fraction (4.8%) of the occurrence records were taken from the literature (see above), largely California records from a taxonomic treatment with some additional records for the two introduced species (Anthidium manicatum and A. oblongatum). These records are highlighted in the Darwin Core [DWC] fields “Associated References” and “Occurrence Remarks” as well as a denoted with a “PUB” prefix in the catalog number.

Method steps

1. Two separate work flows were employed for data capture, which differed fundamentally on where in the process material was determined by the revisionary authors. Retroactive data capture (Fig. 7) incorporated loaned specimens, publication records, and previously non-databased specimens in the U. S. National Pollinating Insects Collection, all of which follows after the identification process. Publication records were treated similarly to retroactive data capture except each record represents a summation of males and females with identical collecting event data. Beginning in 2005, new specimen records (Fig. 8) were batch entered into the database for projects and opportunistic collection events alike. Specimen identification and subsequent update to the database occurred after record and event metadata had been entered. New specimen collections also had a work flow that resulted in a greater number of data quality checks by technicians and primary researchers.
2. Dataset description: AnthWest is a result of a broadly comparative study on the diversity, biology, biogeography, and evolution of bees in the genus Anthidium in the Western Hemisphere. The dataset includes 22,648 occurrence records for 92 species of Anthidium, including two introduced species from Eurasia. Each record consists of the species name, locality, collector’s name, collection date, latitude, longitude, host plants, associated organisms, name of identifier, taxonomic value (i.e., type specimen, voucher, etc.), and repository. When coordinates for collection sites were not provided on the label, they were extracted using Google EarthTM (http://earth.google.com/) or GEOlocate (http://www.museum.tulane.edu/geolocate/). To guarantee the high quality of the data, most records in the dataset correspond to individual specimens examined by the authors during this project, representing 61 biodiversity collections in Europe, Africa, North and South America (Fig. 3). A small fraction (4.8%) of the occurrence records were extracted from the literature. Only literature records for which there was a high degree of certainty in the identification were included. The vast majority of these published records were taken from the rigorous study of California Anthidiini by Grigarick and Stange (1968). Their records were included for all Anthidium species except A. atripes and A. emarginatum, which in Gonzalez and Griswold (2013) are recognized as species complexes. The balance, 30 records of the introduced A. manicatum and A. oblongatum (Miller et al. 2002, Maier 2009, Tonietto and Ascher 2008), were included because these are distinctive species that could not be confused with any native species nor with each other. As with most other bees, floral resources are essential for reproductive success of Anthidium. Floral records indicate a broad array of floral visitation based on the quarter (24%) of AnthWest records that include floral visits. While visitation includes 56 plant families and over 100 species, Fabaceae and Boraginaceae dominated the dataset, together accounting for 75% of the records (Fig. 5). Analysis of plant records at the generic level similarly shows the dominance of Fabaceae and Boraginaceae; all top ten floral associations belong to these two families, but Phacelia, the most visited genus belongs not to Fabaceae but to Boraginaceae (Fig. 6). Records for 34 name-bearing types of Anthidium are also included in the database.

The coverage of this dataset includes all 92 species of the bee genus Anthidium known to occur in the Western Hemisphere, including two that are introduced. Anthidium belongs to the tribe Anthidiini and is among the most diverse genera of the family Megachilidae. Based on the materials used in nest construction, anthidiines are broadly classed into two groups, carder bees and resin bees. While resin bees are generically diverse in the Western Hemisphere, Anthidium is the sole representative of carder bees in the Americas. As such this dataset documents all of a functional bee group for the Americas. The greatest number of data records are for two widespread western North American species, A. utahense Swenk (2409 records) and A. mormonum Cresson (1615 records) (Fig. 4). The species with the least number of records are A. alsinai Urban A. isabelae Urban, A. larocai Urban, A. luizae Urban, A. multispinosum Gonzalez & Griswold, A. neffi Gonzalez & Griswold, and A. rozeni Urban, each represented by a single data record. Though these species are rare in collections, there is no knowledge whether they are rare in nature, though at least for A. multispinosum, it is likely that it has a restricted distribution. No Anthidium in the Western Hemisphere have formally been listed as threatened or endangered. Anthidium are occasionally associated with rare, threaten or endangered plants. Only a handful of such associations with state and/or federally listed plant bee records are included in the dataset (Table 2). Published records provide georeference only to the nearest degree, and floral host, month and day fields will have information hidden. The table below lists Anthidium species associated with State and/or Federally listed plants in the USDA, NRCS PLANTS database. All specimens in this dataset have been reviewed by the authors or are easily determined taxa that have been reviewed by experts in bee taxonomy (e.g., John Ascher, for some AMNH material; A. A. Grigarick and L. A. Stange for California records in Grigarick and Stange 1968). Records with questionable determinations, label information or data have been withheld.

1. Anthidium
   common name: wool-carder bees rank: genus

The database covers a wide range of ecosystems found in both North and South America, from -62° to 79° in latitude and -174° to -22° in longitude. A large portion of the records in North America are from xeric regions (Great Basin, Colorado Plateau, Mojave, Sonoran, and Chihuahuan Deserts) and Mediterranean California, while those from South America are mostly from the xeric regions on the flanks of the Andes (Figs. 1, 2). No records for Anthidium are known from the Caribbean islands. Much of the data set comes from general bee collecting. Additional material in western United States comes from multi-year intensive, systematic bee faunal studies in protected landscapes. While the majority of species of Anthidium occupy a small number of ecoregions (< 5), some species such as A. tenuiflorae Cockerell are widespread, occurring in as many as 41 ecoregions. Many Anthidium have distributions that include critical, endangered, or vulnerable, as well as relatively stable or intact, ecoregions (Table 1) based on WWF (World Wild Fund for Nature) designations (Olson and Dinerstein 2002). Known distributions for 16 species are largely or entirely within critical or endangered ecoregions with at least 90% of collection records from such designated areas. An additional 22 species had at least 90% of collection records from within vulnerable ecoregions. Few native Anthidium spanned both Nearctic and Neotropic Realms (8.8%).