Abstract
To date, the knowledge of bee diversity in the Baja California Peninsula has primarily relied on large, sporadic expeditions from the first half of the 20th century. To address the knowledge gaps, we conducted extensive fieldwork from 2019 to 2023, visited entomological collections in Mexico and USA, and accessed digital databases and community science platforms to compile records. As a result of our field surveys, we identified 521 morphospecies, with 350 recognized as valid species, including 96 new records for the Baja California Peninsula and 68 new findings for Mexico, including the rediscovery of Megachile seducta Mitchell, 1934, ranked as possibly extinct. Additionally, museum visits added 24 new species records for the peninsula, including 12 new to Mexico. Integrating the new and existing records results in a comprehensive checklist that documents 728 species for the peninsula, 613 for Baja California, and 300 for Baja California Sur. Notably, 62 species are endemic to the peninsula, of which 22 are only found in Baja California, and 23 in Baja California Sur. Our findings show a greater bee diversity in northern latitudes, with a sharp decrease to the central and southern peninsula, which corresponds to the geographic distribution of the records. This supports the premise that the Baja California peninsula remains an unexplored area and highlights the importance of conducting studies like the one presented here.
References
- Aguilera-Molina, V.M., Munguia-Ortega, K.K., Lopez-Reyes, E., Martinez-Aquino, A. & Ceccarelli, F.S. (2019) Climate change and forest plagues: assessing current and future impacts of diprionid sawflies on the pine forests of north-western Mexico. PeerJ, 7 (e7220), 1–17. https://doi.org/10.7717/peerj.7220 DOI: https://doi.org/10.7717/peerj.7220
- Almeida, E.A., Bossert, S., Danforth, B.N., Porto, D.S., Freitas, F.V., Davis, C.C., Murray E.A., Blaimer B.B., Spasojevic, T., Ströher, P.R., Orr, M.C., Packer, L., Brady, S.G., Kuhlmann, M., Branstetter, M.G. & Pie, M.R. (2023) The evolutionary history of bees in time and space. Current Biology, 33 (16), 1–14. https://doi.org/10.1016/j.cub.2023.07.005 DOI: https://doi.org/10.1016/j.cub.2023.07.005
- Andrews, F.G. & Gilbert, A.J. (2005) A preliminary annotated checklist and evaluation of the diversity of the Chrysomelidae (Coleoptera) of the Baja California peninsula, Mexico. Insecta Mundi, 19 (1–2), 89–116.
- Ascher, J.S. & Pickering, J. (2024) Discover Life—Bee species guide and world checklist (Hymenoptera: Apoidea: Anthophila). [Draft 56, 21 August 2022] Available from: http://www.discoverlife.org/mp/20q?guide=Apoidea_species&flags=HAS (accessed 2 May 2024)
- Ayala, R., Griswold, T.L. & Bullock, S.H. (1993) The native bees of Mexico. In: Ramamoorthy, T.P., Bye, R., Lot, A. & Fa, J. (Eds.), Biological Diversity of Mexico: Origins and distribution. Oxford University Press, New York, pp. 179–227.
- Ayala, R., Griswold, T.L. & Yanega, D. (1996) Apoidea (Hymenoptera). In: Llorente, J., García- Aldrete, A.N. & González, E. (Eds.), Biodiversidad Taxonomía y Biogeografía de Artrópodos de México. 27. UNAM-CONABIO, México, D.F., pp. 423–464.
- Baker, J.R. (1975) Taxonomy of five Nearctic subgenera of Coelioxys (Hymenoptera: Megachile). The University of Kansas Science Bulletin, 50 (12), 649–730.
- Berrian, J.E., Ruiz, F.M. & Clark, W.H. (2010) New records of spiders for San Diego County, California, USA and Baja California, México. The Pan-Pacific Entomologist, 86 (1), 10–13. https://doi.org/10.3956/2009-23a.1 DOI: https://doi.org/10.3956/2009-23a.1
- Biella, P., Ćetković, A., Gogala, A., Neumayer, J., Sárospataki, M., Šima, P. & Smetana, V. (2021) Northwestward range expansion of the bumblebee Bombus haematurus into Central Europe is associated with warmer winters and niche conservatism. Insect Science, 28 (3), 861–872. https://doi.org/10.1111/1744-7917.12800 DOI: https://doi.org/10.1111/1744-7917.12800
- Bohart, G.E. (1949) New North American bees of the genus Dufourea (Apoidea: Halictidae) Part III. Annals of the Entomological Society of America, 42 (1), 55–62. https://doi.org/10.1093/aesa/42.1.55 DOI: https://doi.org/10.1093/aesa/42.1.55
- Bohart, G.E. & Griswold, T.L. (1987) A revision of the dufoureine genus Micralictoides Timberlake (Hymenoptera, Halictidae). The Pan-Pacific Entomologist, 63 (2), 178–193.
- Bosch, J. & Kemp, W.P. (2000) Development and emergence of the orchard pollinator Osmia lignaria (Hymenoptera: Megachilidae). Environmental Entomology, 29 (1), 8–13. https://doi.org/10.1603/0046-225X-29.1.8 DOI: https://doi.org/10.1603/0046-225X-29.1.8
- Bossert, S., Copeland, R.S., Sless, T.J., Branstetter, M.G., Gillung, J.P., Brady, S.G., Danforth B.N., Policarová J. & Straka, J. (2020) Phylogenomic and morphological reevaluation of the bee tribes Biastini, Neolarrini, and Townsendiellini (Hymenoptera: Apidae) with description of three new species of Schwarzia. Insect Systematics and Diversity, 4 (6), 1–29. https://doi.org/10.1093/isd/ixaa013 DOI: https://doi.org/10.1093/isd/ixaa013
- Bossert, S., Murray, E.A., Almeida, E.A., Brady, S.G., Blaimer, B.B. & Danforth, B.N. (2019) Combining transcriptomes and ultraconserved elements to illuminate the phylogeny of Apidae. Molecular phylogenetics and evolution, 130 (2019), 121–131. https://doi.org/10.1016/j.ympev.2018.10.012 DOI: https://doi.org/10.1016/j.ympev.2018.10.012
- Bossert, S., Wood, T.J., Patiny, S., Michez, D., Almeida, E.A., Minckley, R.L., Packer L., Neff J.L., Copeland R.S., Straka, J., Pauly A., Griswold, T., Brady, S.G., Danforth, B.N. & Murray, E.A. (2022) Phylogeny, biogeography and diversification of the mining bee family Andrenidae. Systematic Entomology, 47 (2), 283–302. https://doi.org/10.1111/syen.12530 DOI: https://doi.org/10.1111/syen.12530
- Bouseman, J.K. & LaBerge, W.E. (1978) A revision of the bees of the genus Andrena of the Western Hemisphere. Part IX. Subgenus Melandrena. Transactions of the American Entomological Society, 104 (3/4), 275–389.
- Ceccarelli, F.S., Aguilera-Molina, V.M., Munguía-Ortega, K.K. & López-Reyes, E. (2022) Hyperparasitism in a jeffrey pine (pinus jeffreyi) defoliator in the Sierra San Pedro Mártir National Park, Baja California, Mexico. The Southwestern Naturalist, 65 (3–4), 268–271. https://doi.org/10.1894/0038-4909-65.3-4.268 DOI: https://doi.org/10.1894/0038-4909-65.3-4.268
- Ceccarelli, F.S., Garduño-Villaseñor, L.A. & Hernández-Salgado, L.C. (2023) Genetic diversity and population histories of two species of Phidippus (Araneae: Salticidae) from northwestern Mexico. Revista Mexicana de Biodiversidad, 94 (2023), e945052. https://doi.org/10.22201/ib.20078706e.2023.94.5052 DOI: https://doi.org/10.22201/ib.20078706e.2023.94.5052
- Clark, W.H., Blom, P.E. & Ward Jr., D.M. (2007) Plant associations for adult Moneilema michelbacheri Linsley (Coleoptera: Cerambycidae), including a new host plant record, the Barrel Cactus (Ferocactus gracilis Gates), in Baja California, México. The Coleopterists’ Bulletin, 61 (2), 294–296. https://doi.org/10.1649/0010-065X(2007)61[294:PAFAMM]2.0.CO;2 DOI: https://doi.org/10.1649/0010-065X(2007)61[294:PAFAMM]2.0.CO;2
- Cockerell, T.D.A. (1899) Catálogo de las abejas de México. Biblioteca Agrícola de la Secretaría de Fomento, 15, 1–20. https://doi.org/10.5962/bhl.title.60192 DOI: https://doi.org/10.5962/bhl.title.60192
- Cockerell, T.D.A. (1923) VII: Expedition of the California Academy of Sciences to the Gulf of California in 1921: The Bees (I). Proceedings of the California Academy of Sciences, 7 (7), 73–103.
- Cockerell, T.D.A. (1924) VII: Expedition of the California Academy of Sciences to the Gulf of California in 1921: The Bees (II). Proceedings of the California Academy of Sciences, 7 (27), 529–560.
- Cockerell, T.D.A. (1925) XI: Bees in the collection of California Academy of Sciences. Proceedings of the California Academy of Sciences, 14 (11), 185–215.
- Cockerell, T.D.A. (1941) Observations on plants and insects in northwestern Baja California, Mexico, with descriptions of new bees. Transactions of the San Diego Society of Natural History, 9 (31), 339–352.
- Cresson, E.T. (1878) Descriptions of new North American Hymenoptera in the collection of the American Entomological Society. Transactions of the American Entomological Society and Proceedings of the Entomological Section of the Academy of Natural Sciences, 7, 61–136. https://doi.org/10.2307/25076368 DOI: https://doi.org/10.2307/25076368
- Danforth, B.N. (1994) Taxonomic review of Calliopsis subgenus Hypomacrotera (Hymenoptera: Andrenidae), with special emphasis on the distributions and host plant associations. The Pan-Pacific Entomologist, 70 (4), 283.
- Danforth, B.N. (1996) Phylogenetic analysis and taxonomic revision of the Perdita subgenera Macrotera, Macroteropsis, Macroterella and Cockerellula (Hymenoptera: Andrenidae). The University of Kansas Science Bulletin, 55 (16), 635.
- Danforth, B.N., Minckley, R.L. & Neff, J.L. (2019) The solitary bees: biology, evolution, conservation. Princeton University Press, Princeton, New Jersey, 488 pp. https://doi.org/10.1515/9780691189321 DOI: https://doi.org/10.1515/9780691189321
- Dorchin, A., Danforth, B. & Griswold, T.L. (2018) A new genus of eucerine bees endemic to southwestern North America revealed in phylogenetic analyses of the Eucera complex (Hymenoptera: Apidae: Eucerini). Arthropod Systematics & Phylogeny, 76 (2), 215–234. https://doi.org/10.3897/asp.76.e31927 DOI: https://doi.org/10.3897/asp.76.e31927
- Ely, C.V., Bordignon, S.A.L., Trevisan, R. & Boldrini, I.I. (2017) Implications of poor taxonomy in conservation. Journal for Nature Conservation, 36 (2017), 10–13. https://doi.org/10.1016/j.jnc.2017.01.003 DOI: https://doi.org/10.1016/j.jnc.2017.01.003
- Engler, J.D., Gorman, M., Cappaert, D., Stanton, M., Best, L.R. & Jackson, A.S. (2024) Bees of the Pacific Northwest: key to Lasioglossum species for females of the Subgenera Hemihalictus, Sphecodogastra, and Evylaeus in Oregon (Hymenoptera: Halictidae). Department of Horticulture, Oregon State University, Corvallis, Oregon, 56 pp. https://doi.org/10.5399/osu/1171 DOI: https://doi.org/10.5399/osu/1171
- Falcón-Brindis, A., Ayala, R., Jiménez, M.L. & Hinojosa-Díaz, I.A. (2018) A missing piece in the puzzle: the presence of Euglossa viridissima in the Baja California Peninsula (Hymenoptera, Apidae). ZooKeys, 726, 15–23. https://doi.org/10.3897/zookeys.726.19876 DOI: https://doi.org/10.3897/zookeys.726.19876
- Falcón‐Brindis, A., Jimenez-Jimenez, M.L. & Rodríguez‐Estrella, R. (2020) Islands in the desert for cavity‐nesting bees and wasps: Ecology, patterns of diversity, and conservation at oases of Baja California Peninsula. Ecology and Evolution, 10 (1), 527–542. https://doi.org/10.1002/ece3.5927 DOI: https://doi.org/10.1002/ece3.5927
- Falcon-Brindis, A. & León-Cortés, J.L. (2023) The oases of Baja California Peninsula: overlooked hotspots for wild bees. Journal of Insect Conservation, 27 (1), 117–128. https://doi.org/10.1007/s10841-022-00432-0 DOI: https://doi.org/10.1007/s10841-022-00432-0
- Falcón-Brindis, A., Rodríguez-Estrella, R. & Jiménez, M.L. (2019) Disentangling the coexistence strategies of mud-daubing wasp species through trophic analysis in oases of Baja California peninsula. PLoS ONE, 14 (11), e0225266. https://doi.org/10.1371/journal.pone.0225266 DOI: https://doi.org/10.1371/journal.pone.0225266
- Fowler, J. (2020) Pollen specialist bees of the western United States. Available from: https://jarrodfowler.com/pollen_specialist.html (accessed 12 May 2024)
- Fox, W.J. (1893) Report on some Mexican Hymenoptera, principally from Lower California. Proceedings of the California Academy of Sciences, Series 2, 4, 1–25.
- Fox, W.J. (1894) Second report on some Hymenoptera from Lower California, Mexico. Proceedings of California Academy of Sciences, Series 2, 4, 92–121
- Gardner, J. & Gibbs, J. (2020) The ‘red-tailed’ Lasioglossum (Dialictus) (Hymenoptera: Halictidae) of the western Nearctic. European Journal of Taxonomy, 725, 1–242. https://doi.org/10.5852/ejt.2020.725.1167 DOI: https://doi.org/10.5852/ejt.2020.725.1167
- Gardner, J. & Gibbs, J. (2023) Revision of the Nearctic species of the Lasioglossum (Dialictus) gemmatum species complex (Hymenoptera: Halictidae). European Journal of Taxonomy, 858, 1–222. https://doi.org/10.5852/ejt.2023.858.2041 DOI: https://doi.org/10.5852/ejt.2023.858.2041
- Garnett, S.T., Christidis, L., Conix, S., Costello, M.J., Zachos, F.E., Bánki, O.S., Bao, Y., Barik, S.K., Buckeridge, J.S., Hobern, D., Lien, A., Montgomery, N., Nikolaeva, S., Pyle, R.L., Thomson, S.A., van Dijk, P.P., Whalen, A., Zhang, Z.Q. & Thiele, K.R. (2020) Principles for creating a single authoritative list of the world’s species. PLoS Biology, 18 (7), e3000736. https://doi.org/10.1371/journal.pbio.3000736 DOI: https://doi.org/10.1371/journal.pbio.3000736
- GBIF (2023) GBIF Occurrence Download. https://doi.org/10.15468/dl.jzq6tm
- Gibbs, J. (2010) Revision of the metallic species of Lasioglossum (Dialictus) in Canada (Hymenoptera, Halictidae, Halictini). Zootaxa, 2591 (1), 1–382. https://doi.org/10.11646/zootaxa.2591.1.1 DOI: https://doi.org/10.11646/zootaxa.2591.1.1
- Gibbs, J. (2012) Two replacement names for North American Lasioglossum (Dialictus) (Hymenoptera: Halictidae). Journal of the Kansas Entomological Society, 85 (3), 259–261. https://doi.org/10.2317/JKES120424.1 DOI: https://doi.org/10.2317/JKES120424.1
- Gibbs, J. (2018) DNA barcoding a nightmare taxon: assessing barcode index numbers and barcode gaps for sweat bees. Genome, 61 (1), 21–31. https://doi.org/10.1139/gen-2017-0096 DOI: https://doi.org/10.1139/gen-2017-0096
- Gonzalez, V.H. & Griswold, T.L. (2013) Wool carder bees of the genus Anthidium in the Western Hemisphere (Hymenoptera: Megachilidae): diversity, host plant associations, phylogeny, and biogeography. Zoological Journal of the Linnean Society, 168 (2), 221–425. https://doi.org/10.1111/zoj.12017 DOI: https://doi.org/10.1111/zoj.12017
- González-Abraham, C.E. Garcillán, P.P. & Ezcurra, E. (2010) Ecorregiones de la península de Baja California: una síntesis. Boletín de la sociedad botánica de México, 87 (2010), 69–82. https://doi.org/10.17129/botsci.302 DOI: https://doi.org/10.17129/botsci.302
- Grigarick, A.A. & Stange, L.A. (1968) The pollen-collecting bees of the Anthidiini of California (Hymenoptera: Megachilidae). Bulletin of the California Insect Survey, 9, 1–113.
- Hernández Salgado, L.C., Guerrero Fuentes, D.R., Garduño Villaseñor, L.A., Castañeda Betancur, L., López Reyes, E. & Ceccarelli, F.S. (2022) New distributional records of Phidippus (Araneae: Salticidae) for Baja California and Mexico: an integrative approach. Diversity, 14 (3), 159. https://doi.org/10.3390/d14030159 DOI: https://doi.org/10.3390/d14030159
- Hortal, J., de Bello, F., Diniz-Filho, J.A.F., Lewinsohn, T.M., Lobo, J.M. & Ladle, R.J. (2015) Seven shortfalls that beset large-scale knowledge of biodiversity. Annual Review of Ecology, Evolution, and Systematics, 46, 523–549. https://doi.org/10.1146/annurev-ecolsys-112414-054400 DOI: https://doi.org/10.1146/annurev-ecolsys-112414-054400
- Hung, K.-L.J., Rightmyer, M.G., Wall, M., Berrian, J., Ascher, J.S., Yanega, D., Davids, J.A. & Holway, D.A. (2015) An annotated checklist of the bees (Hymenoptera: Anthophila) of San Diego County, California. UC San Diego Library Digital Collections. https://doi.org/10.6075/J0PN93HK
- Hurd, P.D. (1958) American bees of the genus Dioxys Lepeletier and Serville (Hymenoptera: Megachilidae). University of California Press, 14 (4), 275–302.
- Hurd Jr., P.D. (1979) Superfamily Apoidea. In: Krombein, K.V. & Hurd Jr., P.D. (Eds.), Catalog of Hymenoptera in America north of Mexico. Smithsonian Institution Press, Washington, D.C., pp. 1199–2209.
- Hurd Jr., P.D. & Linsley, E.G. (1951) The melectine bees of California. Bulletin of the California Insect Survey, 1 (5), 119–140.
- Hurd Jr., P.D. & Linsley, E.G. (1964) The squash and gourd bees—genera Peponapis Robertson and Xenoglossa Smith—inhabiting America north of Mexico (Hymenoptera: Apoidea). Hilgardia, 35 (15), 375–477. https://doi.org/10.3733/hilg.v35n15p375 DOI: https://doi.org/10.3733/hilg.v35n15p375
- Hurd Jr., P.D. & Linsley, E.G. (1966) The Mexican squash and gourd bees of the genus Peponapis (Hymenoptera: Apoidea). Annals of the Entomological Society of America, 59 (4), 835–851. https://doi.org/10.1093/aesa/59.4.835 DOI: https://doi.org/10.1093/aesa/59.4.835
- Hurd Jr., P.D. & Linsley, E.G. (1972) Parasitic bees of the genus Holcopasites Ashmead (Hymenoptera: Apoidea). Smithsonian Contributions in Zoology, 114, 1–41. https://doi.org/10.5479/si.00810282.114 DOI: https://doi.org/10.5479/si.00810282.114
- Hurd Jr., P.D., & Linsley, E.G. (1975) The principal Larrea bees of the southwestern United States (Hymenoptera: Apoidea). Smithsonian Contributions in Zoology, 193, 1–74. https://doi.org/10.5479/si.00810282.193 DOI: https://doi.org/10.5479/si.00810282.193
- Hurd Jr., P.D. & Linsley, E.G. (1976) The bee family Oxaeidae with a revision of the North American species (Hymenoptera, Apoidea). Smithsonian Contributions to Zoology, 220, 1–75. https://doi.org/10.5479/si.00810282.220 DOI: https://doi.org/10.5479/si.00810282.220
- Hurd Jr., P.D. & Michener, C.D. (1955) The megachiline bees of California (Hymenoptera: Megachilidae). Bulletin of the California Insect Survey, 3, 1–248.
- iDigBio (2023) iDigBio Occurrence Download. Available from: https://s.idigbio.org/idigbio-downloads/a53088df-50e6-4c25-a172-faab71881a1f.zip (accessed 22 March 2024)
- International Commission of Zoological Nomenclature (1999) International Code of Zoological Nomenclature. 4th Edition. International Trust for Zoological Nomenclature, London, XXIX + 306 pp. [https://www.iczn.org/the-code/the-international-code-of-zoological-nomenclature/the-code-online/] https://doi.org/10.5962/bhl.title.50608 DOI: https://doi.org/10.5962/bhl.title.50608
- IPBES (2016) The assessment report of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services on pollinators, pollination and food production. In: Potts, S.G., Imperatriz-Fonseca, V.L. & Ngo, H.T. (Eds.), Secretariat of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services. IPBES secretariat, Bonn, 552 pp. [https://www.ipbes.net/assessment-reports/pollinators]
- IUCN (2022) The IUCN Red List of Threatened Species. Version 2022-2. Available from: https://www.iucnredlist.org (accessed 1 March 2023)
- Jaureguiberry, P., Titeux, N., Wiemers, M., Bowler, D.E., Coscieme, L., Golden, A.S., Guerra, C.A., Jacob, U., Takahashi, Y., Settele, J., Díaz, S., Molnár, Z. & Purvis, A. (2022) The direct drivers of recent global anthropogenic biodiversity loss. Science Advances, 8 (45), eabm9982. https://doi.org/10.1126/sciadv.abm9982 DOI: https://doi.org/10.1126/sciadv.abm9982
- Jiménez, M.L. & Palacios-Cardiel, C. (2012) Registros nuevos de arañas para el estado de Baja California, México. Acta zoológica mexicana, 28 (3), 649–658. https://doi.org/10.21829/azm.2012.283871 DOI: https://doi.org/10.21829/azm.2012.283871
- Kavanaugh, D.H. & Clark, W.H. (2012) Prolixocupes lobiceps (LeConte) on the Baja California Peninsula: First records for suborder Archostemata (Insecta: Coleoptera) and family Cupedidae from México. The Pan-Pacific Entomologist, 88 (4), 423–430. https://doi.org/10.3956/2012-50.1 DOI: https://doi.org/10.3956/2012-50.1
- Kleijn, D., Winfree, R., Bartomeus, I., Carvalheiro, L.G., Henry, M., Isaacs, R., Klein, M.A., Kremen, C., M’Gonigle, L.K., Rader, R., Ricketts, T.H., Williams, N.M., Adamson, N.L., Ascher, J.S., Báldi, A., Batáry, P., Benjamin, F., Biesmeijer, J.C., Blitzer, E.J., Bommarco, R., Brand, M.R., Bretagnolle, V., Button, L., Cariveau, D.P., Chifflet, R., Colville, J.F., Danforth, B.N., Elle, E., Garratt, M.P.D., Herzog, F., Holzschuh, A., Howlett, B.G., Jauker, F., Jha, S., Knop, E., Krewenka, K.M., Le Féon, V., Mandelik, Y., May, E.A., Park, M.G., Pisanty, G., Reemer, M., Riedinger, V., Rollin, O., Rundlöf, M., Sardiñas, H.S., Scheper, J., Sciligo, A.R., Smith, H.G., Steffan-Dewenter, I., Thorp, R., Tscharntke, T., Verhulst, J., Viana, B.F., Vaissière, B.E., Veldtman, R., Ward, K.L., Westphal, C. & Potts, S.G. (2015) Delivery of crop pollination services is an insufficient argument for wild pollinator conservation. Nature communications, 6 (1), 7414. https://doi.org/10.1038/ncomms8414 DOI: https://doi.org/10.1038/ncomms8414
- Klein, A.M., Vaissière, B.E., Cane, J.H., Steffan-Dewenter, I., Cunningham, S.A., Kremen, C. & Tscharntke, T. (2007) Importance of pollinators in changing landscapes for world crops. Proceedings of the Royal Society B: Biological Sciences, 274 (1608), 303–313. https://doi.org/10.1098/rspb.2006.3721 DOI: https://doi.org/10.1098/rspb.2006.3721
- Klein, A.M., Boreux, V., Fornoff, F., Mupepele, A.C. & Pufal, G. (2018) Relevance of wild and managed bees for human well-being. Current Opinion in Insect Science, 26, 82–88. https://doi.org/10.1016/j.cois.2018.02.011 DOI: https://doi.org/10.1016/j.cois.2018.02.011
- Koh, I., Lonsdorf, E.V., Williams, N.M., Brittain, C., Isaacs, R., Gibbs, J. & Ricketts, T.H. (2016) Modeling the status, trends, and impacts of wild bee abundance in the United States. Proceedings of the National Academy of Sciences, 113 (1), 140–145. https://doi.org/10.1073/pnas.1517685113 DOI: https://doi.org/10.1073/pnas.1517685113
- LaBerge, W.E. (1956) A revision of the bees of the genus Melissodes in North and Central America. Part I (Hymenoptera, Apidae). University of Kansas Science Bulletin, 37 (18), 911–1194. https://doi.org/10.5962/bhl.part.24549 DOI: https://doi.org/10.5962/bhl.part.24549
- LaBerge, W.E. (1957) The genera of bees of the tribe Eucerini in North and Central America (Hymenoptera, Apoidea). American Museum Novitates, 1837, 1–44.
- LaBerge, W.E. (1958) Notes on the North and Central American bees of the genus Svastra Holmberg (Hymenoptera: Apidae). Journal of the Kansas Entomological Society, 31 (4), 266–273.
- LaBerge, W.E. (1961) A revision of the bees of the genus Melissodes in North and Central America. Part III (Hymenoptera, Apidae). University of Kansas Science Bulletin, 42 (5), 283–663. https://doi.org/10.5962/bhl.part.9821 DOI: https://doi.org/10.5962/bhl.part.9821
- LaBerge, W.E. (1963) New species and records of little-known species of Melissodes from North America (Hymenoptera: Anthophoridae). The University of Nebraska State Museum, 4 (10), 227–242.
- LaBerge, W.E. (1971) A revision of the bees of the genus Andrena of the Western Hemisphere. Part IV. Scrapteropsis, Xiphandrena, and Rhaphandrena. Transactions of the American Entomological Society, 97 (3), 441–520.
- LaBerge, W.E. (1977) A revision of the bees of the genus Andrena of the western hemisphere. Part VIII. Subgenera Thysandrena, Dasyandrena, Psammandrena, Rhacandrena, Euandrena, Oxyandrena. Transactions of the American Entomological Society, 103 (1), 1–143.
- LaBerge, W.E. (1985) A revision of the bees of the genus Andrena of the western hemisphere. Part XI. Minor subgenera and subgeneric key. Transactions of the American Entomological Society, 111 (4), 441–567.
- LaBerge, W.E. (1986) A revision of the bees of the genus Andrena of the Western Hemisphere. Part XII. Subgenera Leucandrena, Ptilandrena, Scoliandrena and Melandrena. Transactions of the American Entomological Society, 112 (3), 191–248.
- LaBerge, W.E. (1989) A revision of the bees of the genus Andrena of the Western Hemisphere. Part XIII. Subgenera Simandrena and Taeniandrena. Transactions of the American Entomological Society, 115 (1), 1–56.
- LaBerge, W.E. (2001) Revision of the bees of the genus Tetraloniella in the New World (Hymenoptera: Apidae). Illinois Natural History Survey Bulletin, 36 (1–5), 67–162. https://doi.org/10.21900/j.inhs.v36.125 DOI: https://doi.org/10.21900/j.inhs.v36.125
- LaBerge, W.E. & Bouseman, J.K. (1970) A revision of the bees of the genus Andrena of the Western Hemisphere. Part III. Tylandrena. Transactions of the American Entomological Society, 96 (4), 543–605.
- LaBerge, W.E. & Bouseman, J.K. (1977) On the systematic position of three black Andrena from Western North America (Hymenoptera: Andrenidae). Journal of the Kansas Entomological Society, 50 (4), 601–612.
- LaBerge, W.E. & Ribble, D.W. (1972) A revision of the bees of the genus Andrena of the western hemisphere. Part V. Gonandrena, Geissandrena, Parandrena, Pelicandrena. Transactions of the American Entomological Society, 98 (3), 271–358.
- LaBerge, W.E. & Thorp, R.W. (2005) A revision of the bees of the genus Andrena of the Western Hemisphere: Part XIV—Subgenus Onagrandrena. Illinois Natural History Survey Bulletin, 37 (1–6), 1–64. https://doi.org/10.21900/j.inhs.v37.119
- Lincoln, P.G. (1980) Phylogeny, Host Plant Relations and Speciation in Genus Dufourea (Hymenoptera; Apoidea). PhD dissertation, University of California, Santa Cruz, California, 307 pp.
- Linsley, E.G. (1943) Revisions of the genera Townsendiella, Triopasites and Paranomada (Hymenoptera: Nomadidae). Transactions of the American Entomological Society, 69 (2/3), 93–106.
- Linsley, E.G. (1958) The ecology of solitary bees. Hilgardia, 27 (19), 543–599. https://doi.org/10.3733/hilg.v27n19p543 DOI: https://doi.org/10.3733/hilg.v27n19p543
- Linsley, E.G. & MacSwain, J.W. (1955) The habits of Nomada opacella Timberlake with notes on other species (Hymenoptera: Anthophoridae). The Wasmann Journal of Biology, 13 (2), 253–276
- Martínez‐López, O., Koch, J.B., Martínez‐Morales, M.A., Navarrete‐Gutiérrez, D., Enríquez, E. & Vandame, R. (2021) Reduction in the potential distribution of bumble bees (Apidae: Bombus) in Mesoamerica under different climate change scenarios: Conservation implications. Global Change Biology, 27 (9), 1772–1787. https://doi.org/10.1111/gcb.15559 DOI: https://doi.org/10.1111/gcb.15559
- McGinley, R.J. (1986) Studies of Halictinae (Apoidea: Halictidae), I: revision of new world Lasioglossum curtis. Smithsonian Contributions to Zoology, 429, 1–294. https://doi.org/10.5479/si.00810282.429 DOI: https://doi.org/10.5479/si.00810282.429
- Meiners, J.M., Griswold, T.L. & Carril, O.M. (2019) Decades of native bee biodiversity surveys at Pinnacles National Park highlight the importance of monitoring natural areas over time. PLoS ONE, 14 (1), e0207566. https://doi.org/10.1371/journal.pone.0207566 DOI: https://doi.org/10.1371/journal.pone.0207566
- MEA (2005) Ecosystems and human well-being. Vol. 5. Island press, Washington, D.C., 563 pp.
- Mérida-Rivas, J.A., Hinojosa-Daz, I.A., Ayala-Barajas, R., Barrientos-Villalobos, S., Pozo, C. & Vandame, R. (2022) Revision of carpenter bees of the subgenus Neoxylocopa Michener (Hymenoptera: Apidae) from Mexico and Mesoamerica. Zootaxa, 5158 (1), 1–67. https://doi.org/10.11646/zootaxa.5158.1.1 DOI: https://doi.org/10.11646/zootaxa.5158.1.1
- Michener, C.D. (1954) Records and descriptions of North American megachilid bees. Journal of the Kansas Entomological Society, 27 (2), 65–78.
- Michener, C.D. (1979) Biogeography of the bees. Annals of the Missouri botanical Garden, 66 (3), 277–347. https://doi.org/10.2307/2398833 DOI: https://doi.org/10.2307/2398833
- Michener, C.D. (2007) The Bees of the World. 2nd Edition. John Hopkins University Press, Baltimore, Maryland, 953 pp. https://doi.org/10.56021/9780801885730 DOI: https://doi.org/10.56021/9780801885730
- Minckley, R.L. & Ascher, J.S. (2013) Preliminary survey of bee (Hymenoptera: Anthophila) richness in the northwestern Chihuahuan Desert. In: Gottfried, G.J., Ffolliott, P.F., Gebow, B.S., Eskew, L.G. & Collins, L.C., Merging science and management in a rapidly changing world: Biodiversity and management of the Madrean Archipelago III and 7th Conference on Research and Resource Management in the Southwestern Deserts. Proceedings RMRS-P-67. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fort Collins, Colorado, pp. 138–143.
- Minckley, R.L. & Radke, W.R. (2021) Extreme species density of bees (Apiformes, Hymenoptera) in the warm deserts of North America. Journal of Hymenoptera Research, 82, 317–345. https://doi.org/10.3897/jhr.82.60895 DOI: https://doi.org/10.3897/jhr.82.60895
- Moure, J.S. & Hurd Jr., P.D. (1987) An annotated catalog of the halictid bees of the western hemisphere (Hymenoptera: Halictidae). Smithsonian Institution Press, Washington, D.C., 405 pp.
- Munguía-Ortega, K.K., López-Reyes, E. & Ceccarelli, F.S. (2021) Testing the accuracy of vegetation-based ecoregions for predicting the species composition of blow flies (Diptera: Calliphoridae). Journal of Insect Science, 21 (1), 1–9. https://doi.org/10.1093/jisesa/ieaa144 DOI: https://doi.org/10.1093/jisesa/ieaa144
- Murphy, R.W. (1983) Paleobiogeography and genetic differentiation of the Baja California herpetofauna. Occasional papers of the California Academy of Sciences, 137, 1–48
- Nava-Bolaños, A., Osorio-Olvera, L. & Soberón, J. (2022) Estado del arte del conocimiento de biodiversidad de los polinizadores de México. Revista Mexicana de Biodiversidad, 93 (2022), e933948. https://doi.org/10.22201/ib.20078706e.2022.93.3948 DOI: https://doi.org/10.22201/ib.20078706e.2022.93.3948
- Nava-Bolaños, A., Prieto-Torres, D.A., Osorio-Olvera, L., Soberón, J., del Coro Arizmendi, M. & Navarro-Sigüenza, A.G. (2023) Critical areas for pollinator conservation in Mexico: A cross-border priority. Biological Conservation, 283 (110119), 1–12. https://doi.org/10.1016/j.biocon.2023.110119 DOI: https://doi.org/10.1016/j.biocon.2023.110119
- Nava-Bolaños, A. & Soberón, J. (2023) Polinizadores en un Mundo Cambiante. In: Torres, B. & Graizbord, B. (Eds.), Influencias y compromisos internacionales en la política internacional mexicana. El Colegio de México, Ciudad de México, pp. 327–348.
- Nesbitt, M., McBurney, R.P., Broin, M. & Beentje, H.J. (2010) Linking biodiversity, food and nutrition: The importance of plant identification and nomenclature. Journal of food composition and analysis, 23 (6), 486–498. https://doi.org/10.1016/j.jfca.2009.03.001 DOI: https://doi.org/10.1016/j.jfca.2009.03.001
- Ollerton, J. (2017) Pollinator diversity: distribution, ecological function, and conservation. Annual Review of Ecology, Evolution, and Systematics, 48, 353–376. https://doi.org/10.1146/annurev-ecolsys-110316-022919 DOI: https://doi.org/10.1146/annurev-ecolsys-110316-022919
- Onuferko, T.M. (2018) A revision of the cleptoparasitic bee genus Epeolus Latreille for Nearctic species, north of Mexico (Hymenoptera, Apidae). ZooKeys, 755, 1–185. https://doi.org/10.3897/zookeys.755.23939 DOI: https://doi.org/10.3897/zookeys.755.23939.figure10
- Onuferko, T.M., Packer, L. & Genaro, J.A. (2021) Brachymelecta Linsley, 1939, previously the rarest North American bee genus, was described from an aberrant specimen and is the senior synonym for Xeromelecta Linsley, 1939. European Journal of Taxonomy, 754, 1–51. https://doi.org/10.5852/ejt.2021.754.1393 DOI: https://doi.org/10.5852/ejt.2021.754.1393
- Orr, M.C., Branstetter, M.G., Straka, J., Yuan, F., Leijs, R., Zhang, D., Zhou, Q. & Zhu, C.D. (2022) Phylogenomic interrogation revives an overlooked hypothesis for the early evolution of the bee family Apidae (Hymenoptera: Apoidea), with a focus on the subfamily Anthophorinae. Insect Systematics and Diversity, 6 (4), 1–15. https://doi.org/10.1093/isd/ixac022 DOI: https://doi.org/10.1093/isd/ixac022
- Orr, M.C. & Griswold, T.L. (2015) A review of the cleptoparasitic bee genus Townsendiella (Apidae, Nomadinae, Townsendiellini), with the description of a new species from Pinnacles National Park. ZooKeys, 546, 87–104. https://doi.org/10.3897/zookeys.546.6443 DOI: https://doi.org/10.3897/zookeys.546.6443
- Orr, M.C., Hughes, A.C., Chesters, D., Pickering, J., Zhu, C.D. & Ascher, J.S. (2021) Global patterns and drivers of bee distribution. Current Biology, 31 (3), 451–458. https://doi.org/10.1016/j.cub.2020.10.053 DOI: https://doi.org/10.1016/j.cub.2020.10.053
- Orr, M.C., Pitts, J.P. & Griswold, T.L. (2018) Revision of the bee group Anthophora (Micranthophora) (Hymenoptera: Apidae), with notes on potential conservation concerns and a molecular phylogeny of the genus. Zootaxa, 4511 (1), 1–193. https://doi.org/10.11646/zootaxa.4511.1.1 DOI: https://doi.org/10.11646/zootaxa.4511.1.1
- Osterman, J., Aizen, M.A., Biesmeijer, J.C., Bosch, J., Howlett, B.G., Inouye, D.W., Jung, C., Martins, D.J., Medel, R., Pauw, A., Seymour, C.L. & Paxton, R.J. (2021) Global trends in the number and diversity of managed pollinator species. Agriculture, Ecosystems & Environment, 322, 107653. https://doi.org/10.1016/j.agee.2021.107653 DOI: https://doi.org/10.1016/j.agee.2021.107653
- Outhwaite, C.L., McCann, P. & Newbold, T. (2022) Agriculture and climate change are reshaping insect biodiversity worldwide. Nature, 605 (7908), 97–102. https://doi.org/10.1038/s41586-022-04644-x DOI: https://doi.org/10.1038/s41586-022-04644-x
- Parker, F.D. & Griswold, T.L. (2013) New species of the cleptoparasitic bee genus Stelis (Hymenoptera: Megachilidae, Anthidiini) from the Nearctic Region. Zootaxa, 3646 (5), 529–544. https://doi.org/10.11646/zootaxa.3646.5.3 DOI: https://doi.org/10.11646/zootaxa.3646.5.3
- Patiny, S., Michez, D. & Danforth, B.N. (2008) Phylogenetic relationships and host‐plant evolution within the basal clade of Halictidae (Hymenoptera, Apoidea). Cladistics, 24 (3), 255–269. https://doi.org/10.1111/j.1096-0031.2007.00182.x DOI: https://doi.org/10.1111/j.1096-0031.2007.00182.x
- Pisanty, G., Richter, R., Martin, T., Dettman, J. & Cardinal, S. (2022) Molecular phylogeny, historical biogeography and revised classification of andrenine bees (Hymenoptera: Andrenidae). Molecular Phylogenetics and Evolution, 170, 1–16. https://doi.org/10.1016/j.ympev.2021.107151 DOI: https://doi.org/10.1016/j.ympev.2021.107151
- Plant, J.D. & Paulus, H.F. (2016) Evolution and phylogeny of bees. A review and a cladistic analysis in light of morphological evidence (Hymenoptera, Apoidea). Zoologica, 161, 1–364.
- Portman, Z.M. Neff, J.L. & Griswold, T.L. (2016) Taxonomic revision of Perdita subgenus Heteroperdita Timberlake (Hymenoptera: Andrenidae), with descriptions of two ant-like males. Zootaxa, 4214 (1), 1–97. https://doi.org/10.11646/zootaxa.4214.1.1 DOI: https://doi.org/10.11646/zootaxa.4214.1.1
- Potts, S.G., Imperatriz-Fonseca, V., Ngo, H.T., Aizen, M.A., Biesmeijer, J.C., Breeze, T.D., Dicks L.V., Garibaldi L.A., Hill, R., Settele, J. & Vanbergen, A.J. (2016) Safeguarding pollinators and their values to human well-being. Nature, 540 (7632), 220–229. https://doi.org/10.1038/nature20588 DOI: https://doi.org/10.1038/nature20588
- Raw, A. (2007) An annotated catalogue of the leafcutter and mason bees (genus Megachile) of the Neotropics. Zootaxa, 1601 (1), 1–127. https://doi.org/10.11646/zootaxa.1601.1.1 DOI: https://doi.org/10.11646/zootaxa.1601.1.1
- Ribble, D.W. (1968) Revisions of two subgenera of Andrena: Micrandrena (Ashmead) and Derandrena, new subgenus (Hymenoptera: Apoidea). Bulletin of The University of Nebraska State Museum, 8 (5), 237–394.
- Ribble, D.W. (1974) A revision of the bees of the genus Andrena of the western hemisphere subgenus Scaphandrena. Transactions of the American Entomological Society, 100 (2), 101–189.
- Riddle, B.R., Hafner, D.J., Alexander, L.F. & Jaeger, J.R. (2000) Cryptic vicariance in the historical assembly of a Baja California Peninsular Desert biota. Proceedings of the National Academy of Sciences, 97 (26), 14438–14443. https://doi.org/10.1073/pnas.250413397 DOI: https://doi.org/10.1073/pnas.250413397
- Rightmyer, M.G. (2008) A review of the cleptoparasitic bee genus Triepeolus (Hymenoptera: Apidae). Part I. Zootaxa, 1710 (1), 1–170. https://doi.org/10.11646/zootaxa.1710.1.1 DOI: https://doi.org/10.11646/zootaxa.1710.1.1
- Rightmyer, M.G. & Griswold, T.L. (2010) Description of a new species of Osmia (Hymenoptera: Megachilidae) from southwestern North America, with a redescription of the enigmatic species Osmia foxi Cameron. Zootaxa, 2512 (1), 26–46. https://doi.org/10.11646/zootaxa.2512.1.2 DOI: https://doi.org/10.11646/zootaxa.2512.1.2
- Rightmyer, M.G., Kono, Y., Kohn, J.R. & Hung, K.L.J. (2014) A new species of Triepeolus (Hymenoptera: Apidae), with comments on T. utahensis (Cockerell) and T. melanarius Rightmyer. Zootaxa, 3872 (1), 48–56. https://doi.org/10.11646/zootaxa.3872.1.4 DOI: https://doi.org/10.11646/zootaxa.3872.1.4
- Roberts, R.B. (1972) Revision of the bee genus Agapostemon (Hymenoptera: Halictidae). The University of Kansas Science Bulletin, 49 (9), 437–590.
- Rozen Jr., J.G. (1958) Monographic study of the genus Nomadopsis Ashmead (Hymenoptera: Andrenidae). University of California Press, 15, 1–202.
- Rozen Jr., J.G. (1977) Immature stages of and ethological observations on the cleptoparasitic bee tribe Nomadini (Apoidea, Anthophoridae). American Museum Novitates, 2638, 1–16.
- Rozen Jr., J.G. (1992) Systematics and host relationships of the cuckoo bee genus Oreopasites (Hymenoptera, Anthophoridae, Nomadinae). American Museum Novitates, 3046, 1–56.
- Rozen Jr., J.G. (1994) Biologies of the bee genera Ancylandrena (Andrenidae, Andreninae) and Hexepeolus (Apidae, Nomadinae): and phylogenetic relationships of Ancylandrena based on its mature larva (Hymenoptera, Apoidea). American Museum Novitates, 3108, 1–19.
- Rozen Jr., J.G. & McGinley, R.J. (1991) Biology and larvae of the cleptoparasitic bee Townsendiella pulchra and nesting biology of its host Hesperapis larreae (Hymenoptera: Apoidea). American Museum Novitates, 3005, 1–11.
- Rust, R.W. & Bohart, G.E. (1986) New species of Osmia (Hymenoptera: Megachilidae) from the southwestern United States. Entomological News, 97 (4), 147–155.
- Sandhouse, G.A. (1937) The bees of the genera Augochlora, Augochloropsis, and Augochlorella (Hymenoptera; Apoidea) occurring in the United States. Journal of the Washington Academy of Sciences, 27 (2), 65–79.
- Sandhouse, G.A., Cockerell, T.D.A. (1924) VII: Expedition of the California Academy of Sciences to the Gulf of California in 1921: The Bees (III). Proceedings of the California Academy of Sciences, 8 (21), 333–339.
- Sankey-Alamilla, L.A., Hernandez-Jimenez S.A., Lopez-Reyes E. & Ceccarelli, F.S. (2024) New species of honeypot ant of the genus Myrmecocystus from Pacific Coastal Dunes of Baja California, Mexico. Southwestern Entomologist, 49 (1), 71–87. https://doi.org/10.3958/059.049.0107 DOI: https://doi.org/10.3958/059.049.0107
- SCAN (2023) Symbiota collection of arthropods network. Online database. Available from: http://www.scan-bugs.org (accessed 23 June 2023)
- Schlising, R.A. (1972) Foraging and nest provisioning behavior of the oligolectic bee, Diadasia bituberculata (Hymenoptera: Anthophoridae). The Pan-Pacific Entomologist, 48 (3), 175–188.
- Shanks, S.S. (1977) A revision of the cleptoparasitic bee genus Neolarra (Hymenoptera: Anthophoridae). The Wasmann Journal of Biology, 35 (2), 212–246.
- Sheffield, C.S. (2024) A review of the Stelidium group of Stelis Panzer, 1806 (Hymenoptera: Megachilidae) with two new species from western North America. Zootaxa, 5404 (1), 134–166. https://doi.org/10.11646/zootaxa.5404.1.10 DOI: https://doi.org/10.11646/zootaxa.5404.1.10
- Shinn, A.F. (1967) A revision of the bee genus Calliopsis and the biology and ecology of C. andreniformis (Hymenoptera, Andrenidae). University of Kansas Science Bulletin, 46 (21), 753–936. https://doi.org/10.5962/bhl.part.20081 DOI: https://doi.org/10.5962/bhl.part.20081
- Snelling, R.R. (1968) Studies on North American bees of the genus Hylaeus: 4. The subgenera Cephalylaeus, Metziella and Hylaeana (Hymenoptera: Colletidae). Contributions in Science-Los Angeles County Museum, 114, 1–6 https://doi.org/10.5962/p.241133 DOI: https://doi.org/10.5962/p.241133
- Snelling, R.R. (1970) Studies on North American bees of the genus Hylaeus. 5. The subgenera Hylaeus, s. str. and Paraprosopis (Hymenoptera: Colletidae). Contributions in Science-Los Angeles County Museum, 180, 1–59. https://doi.org/10.5962/p.241167 DOI: https://doi.org/10.5962/p.241167
- Snelling, R.R. (1974) Notes on the distribution and taxonomy of some North American Centris (Hymenoptera: Anthophoridae). Contributions in Science-Los Angeles County Museum, 259, 1–41. https://doi.org/10.5962/p.208114 DOI: https://doi.org/10.5962/p.208114
- Snelling, R.R. (1975) Taxonomic notes on some colletid bees of western North America with descriptions of new species (Hymenoptera: Colletidae). Contributions in Science-Los Angeles County Museum, 267, 1–9. https://doi.org/10.5962/p.241249 DOI: https://doi.org/10.5962/p.241249
- Snelling, R.R. & Rozen Jr., J.G. (1987) Contributions toward a revision of the New World nomadine bees. 2. The genus Melanomada (Hymenoptera: Anthophoridae). Contributions in Science-Los Angeles County Museum, 384, 1–12. https://doi.org/10.5962/p.208127 DOI: https://doi.org/10.5962/p.208127
- Snelling, R.R. & Stage, G.I. (1995) Systematics and biology of the bee genus Xeralictus (Hymenopteral: Halictidae: Rophitinae). Contributions in Science-Los Angeles County Museum, 451, 1–17. https://doi.org/10.5962/p.208085 DOI: https://doi.org/10.5962/p.208085
- Stephen, W.P. (1954) A revision of the bee genus Colletes in America north of Mexico (Hymenoptera, Colletidae) University of Kansas Science Bulletin, 36 (6), 149–527.
- Thorp, R.W. & LaBerge, W.E. (2005) A revision of the bees of the genus Andrena of the Western Hemisphere: Part XIV—Subgenus Onagrandrena and Part XV—Subgenus Hesperandrena. Illinois Natural History Survey Bulletin, 37 (1–6), 1–93. https://doi.org/10.21900/j.inhs.v37 DOI: https://doi.org/10.21900/j.inhs.v37.119
- Timberlake, P.H. (1949) The species of Dianthidium of Baja California (Hymenoptera, Megachilidae). The Pan-Pacific Entomologist, 25 (3), 129–132.
- Timberlake, P.H. (1951) New species of Anthophora from the western United States (Hymenoptera, Apoidea). Journal of the New York Entomological Society, 59 (1), 51–62.
- Timberlake, P.H. (1954) A revisional study of the bees of the genus Perdita F. Smith, with special reference to the fauna of the Pacific coast (Hymenoptera, Apoidea) Part I. University of California Publications in Entomology, 9 (6), 345–432.
- Timberlake, P.H. (1958) A revisional study of the bees of the genus Perdita F. Smith, with special reference to the fauna of the Pacific coast (Hymenoptera, Apoidea) Part III. University of California Publications in Entomology, 14 (5), 303–410.
- Timberlake, P.H. (1960) A revisional study of the bees of the genus Perdita F. Smith, with special reference to the fauna of the Pacific coast (Hymenoptera, Apoidea) Part IV. University of California Publications in Entomology, 17 (1), 1–156.
- Timberlake, P.H. (1961) A review of the genus Conanthalictus (Apoidea: Halictidae). The Pan-Pacific Entomologist, 37 (3), 145–160.
- Timberlake, P.H. (1962) A revisional study of the bees of the genus Perdita F. Smith, with special reference to the fauna of the Pacific coast (Hymenoptera, Apoidea) Part V. University of California Publications in Entomology, 28 (1), 1–124.
- Timberlake, P.H. (1968) A revisional study of the bees of the genus Perdita F. Smith, with special reference to the fauna of the Pacific Coast (Hymenoptera, Apoidea) Part Vll (Including Index to Parts l to Vll). University of California Publications in Entomology, 49, 1–196.
- Timberlake, P.H. (1969) A contribution to the systematics of North America species of Synhalonia (Hymenoptera, Apoidea). University of California Publications in Entomology, 57, 1–76.
- Timberlake, P.H. (1971) Supplementary studies on the systematics of the genus Perdita (Hymenoptera, Andrenidae). University of California Publications in Entomology, 66, 1–63.
- Timberlake, P.H. (1975) The North American species of Heterosarus Robertson (Hymenoptera, Apoidea). University of California Publications in Entomology, 77, 1–56.
- Timberlake, P.H. (1977) Descriptions of new species of Perdita (Hymenoptera, Apoidea) in the collection of the California Academy of Sciences. Proceedings of the California Academy of Sciences, 41 (10), 281–295.
- Timberlake, P.H. (1979) Report on Perdita in the collection of the California Academy of Sciences. Wasmann Journal of Biology, 37, 30–39.
- Timberlake, P.H. (1980) Supplementary studies on the systematics of the genus Perdita (Hymenoptera, Andrenidae) Part II. University of California Publications in Entomology, 85, 1–65.
- Timberlake, P.H. (1980b) Review of North American Exomalopsis (Hymenoptera, Anthophoridae). University of California Publications in Entomology, 86, 1–158.
- Torchio, P.F., Rozen Jr., J.G., Bohart, G.E. & Favreau, M.S. (1967) Biology of Dufourea and of its cleptoparasite, Neopasites (Hymenoptera: Apoidea). Journal of the New York Entomological Society, 75 (3), 132–146.
- Truxal, F.S. (1960) The entomofauna with special reference to its origins and affinities. Systematic Biology, 9 (3/4), 165–170. https://doi.org/10.2307/2411964 DOI: https://doi.org/10.2307/2411964
- Vaughan, M., Hopwood, J., Lee-Mäder, E., Shepherd, M., Kremen, C., Stine, A. & Black, S.H. (2015) Farming for bees; Guidelines for Providing Native Bee Habitat on Farms. Fourth edition. The Xerces Society for Invertebrate Conservation, Portland, 76 pp.
- Williams, P.H., Thorp, R.W., Richardson, L.L. & Colla, S.R. (2014) Bumble bees of North America: an identification guide. Princeton University Press, Princeton, 208 pp. https://doi.org/10.1515/9781400851188 DOI: https://doi.org/10.1515/9781400851188
- Young, B.E., Schweitzer, D.F., Hammerson, G.A., Sears, N.A., Ormes, M.F. & Tomaino, A.O. (2016) Conservation and Management of North American Leafcutter Bees. NatureServe, Arlington, Virginia, 24 pp.
- Zavortink, T.J. (1974) A revision of the genus Ancylandrena (Hymenoptera: Andrenidae). Occasional Papers of the California Academy of Sciences, 109, 1–36.