Andrena mojavensis

Justification:
Andrena mojavensis is a solitary bee known from over 500 specimens. However at the time of this assessment, only nine of those were available for analysis as digitized museum specimen records. Records used in analysis come from all three localities listed in the species revision. Using all recorded localities of this species, the extent of occurrence (EOO) is just 61 km2. This species has not been observed since 1970, and thus confidence in the validity of the EOO is low, and a species distribution model cannot be generated. This species is a dietary specialist that collects pollen from the plant genus Camissonia (Onagraceae). Specific threats to this species have not been directly investigated. It may be subject to threats faced by bees generally, including habitat loss, climate change, and exposure to pesticides. More information is needed to determine if this species is still extant. Because the species is currently only known from three localities and records are older than 50 years, it is assessed as Data Deficient for now. However if this species is determined to be extant, it should be reassessed with consideration to rank it as imperiled due to its small EOO.

Food habits comment: Andrena mojavensis is a dietary specialist that collects pollen from the plant genus Camissonia (Onagraceae), with its principal food plant Camissonia kernensis (LaBerge and Thorp 2005). Habitat comment: This species has been recorded in shrubland, between 746 and 945 m. . Reproduction comment: This species nests underground like all other Andrena (Danforth et al. 2019), with nests frequently constructed in sandy soils with vertical entrance shafts (LaBerge and Thorp 2005). Observations of this species’s nest biology describe widely scattered nests, and no tendency towards aggregations (LaBerge and Thorp 2005). Nest cells from other members of this genus are located at the ends of the lateral burrows, which are typically lined with a waxy Dufour’s gland secretion (Cane 1981) that serves to both isolate the provision from pathogens in the surrounding soil and to regulate water uptake from the soil atmosphere (Cane and Love 2021). Females provision each cell with a ball of pollen moistened with nectar on which they lay a single egg (Michener 2007). Phenology comment: Records of this species come from March and April (Chesshire et al. 2023; LaBerge and Thorp 2005). Adults are assumed to emerge annually (Danforth et al. 2019), although in unfavorable conditions, this species may remain in its brood cell for longer than one year to delay untl conditions are more favorable (LaBerge and Thorp 2005).

Threat comments: Specific threats to this species have not been investigated. Certain aspects of this species' biology may make it more vulnerable to some threats. Andrena mojavensis is a ground nesting species, and nests may be harmed by certain agricultural practices such as tilling, which can kill bees nesting close to the surface (Williams et al. 2010). This species is a dietary specialist, which has been linked to higher risk of extinction due to reduced host plant availability, especially under climate change scenarios (Roberts et al. 2011) and reduced effective population sizes (Packer et al. 2005). Additionally, Andrena have been reported to have low reproductive output because of the short adult life span, and a low rate of brood cell provisioning (reviewed in Danforth et al. 2019). Other threats to bees generally include habitat loss or modification, climate change, pesticide use, exposure to pathogens from managed bee species, and competition with honey bees (Brown and Paxton 2009; Potts et al. 2010; Wojcik et al. 2018; Grab et al. 2019; Raven and Wagner 2021). Threats Threats: Timing: Scope: Severity: Impact Score: 1. Residential & commercial development -> 1.1. Housing & urban areas 1. Residential & commercial development -> 1.2. Commercial & industrial areas 2. Agriculture & aquaculture -> 2.1. Annual & perennial non-timber crops -> 2.1.3. Agro-industry farming 7. Natural system modifications -> 7.1. Fire & fire suppression -> 7.1.1.Increase in fire frequency/intensity 7. Natural system modifications -> 7.1. Fire & fire suppression -> 7.1.2. Suppression in fire frequency/intensity 8. Invasive and other problematic species, genes, and diseases -> 8.1 Invasive non-native/alien species/diseases -> 8.1.2. Named species 9. Pollution -> 9.3 Agricultural and forestry effluents -> 9.3.3 Herbicides and Pesticides 11. Climate change & severe weather -> 11.1. Habitat shifting & alteration 11. Climate change & severe weather -> 11.2.Droughts 11. Climate change & severe weather -> 11.3.Temperature extremes Conservation Actions Conservation needs No known conservation actions are in place for this species. Protected/Managed area comment: Observations of this species are known from Bureau of Land Management (BLM) land, but this does not confer any specific protections to the species. Management comment: Specific conservation needs for this species have not been identified. Due to the importance of supporting wild bee populations for pollination services, general conservation practices are recommended including, restoring, creating, and preserving natural high-quality habitats to include suitable forage and nesting sites; limiting pesticide use on or near suitable habitat, particularly during the adult bee’s flight period; promoting farming and urban practices that increase pollinator-friendly plants in margin space; minimizing exposure of wild bees to diseases transferred from managed bees; and lastly, avoiding honey bee introduction to high-quality native bee habitat. Conservation Actions Needed 1. Land/water protection -> 1.2. Resource & habitat protection 2. Land/water management -> 2.3. Habitat & natural process restoration 4. Education & awareness -> 4.3. Awareness & communications 5. Law & policy -> 5.2. Policies and regulations Research needs Research need comment: More information is needed about the population status, population trend, existing threats, range limits, habitat, and ecology of this species. Surveys targeting this species are needed throughout its range to determine its persistence throughout its historic range. Research Needed 1. Research -> 1.2. Population size, distribution & trends 1.3. Life History and Ecology 1.5. Threats 1.6 Conservation actions 3. Monitoring -> 3.1. Population trends 3.4. Habitat trends Assessment Date of assessment (month-day-year): 8-11-2025 Assessors names (use * to indicate primary assessor, typically the participant with most experience/knowledge of the species): Saff Killingsworth Reviewer(s): Contributors(s): For a full list of the 162 institutions that contributed to the Chesshire et al. dataset, please see Chesshire et al. 2023, S1. Facilitator(s) and compiler(s): Paige R. Chesshire, Erica E. Fischer, Nicolas J. Dowdy, Terry L. Griswold, Alice C. Hughes, Michael C. Orr, John S. Ascher, Laura M. Guzman, Keng-Lou James Hung, Neil S. Cobb and Lindsie M. McCabe Red List Category and Criteria: Data Deficient Justification: Andrena mojavensis is a solitary bee known from over 500 specimens. However at the time of this assessment, only nine of those were available for analysis as digitized museum specimen records. Records used in analysis come from all three localities listed in the species revision. Using all recorded localities of this species, the extent of occurrence (EOO) is just 61 km2. This species has not been observed since 1970, and thus confidence in the validity of the EOO is low, and a species distribution model cannot be generated. This species is a dietary specialist that collects pollen from the plant genus Camissonia (Onagraceae). Specific threats to this species have not been directly investigated. It may be subject to threats faced by bees generally, including habitat loss, climate change, and exposure to pesticides. More information is needed to determine if this species is still extant. Because the species is currently only known from three localities and records are older than 50 years, it is assessed as Data Deficient for now. However if this species is determined to be extant, it should be reassessed with consideration to rank it as imperiled due to its small EOO. Rank reasons This species is a solitary bee known from over 500 specimens. However at the time of this assessment, only nine of those were available for analysis as digitized museum specimen records. Records used in analysis come from all three localities listed in the species revision. Using all recorded localities of this species, the range extent is just 61 km2. This species has not been observed since 1970, and thus confidence in the validity of the range extent is low, and a species distribution model cannot be generated. This species is a dietary specialist that collects pollen from the plant genus Camissonia (Onagraceae). Specific threats to this species have not been directly investigated. It may be subject to threats faced by bees generally, including habitat loss, climate change, and exposure to pesticides. More information is needed to determine if this species is still extant. Because the species is currently only known from three localities and records are older than 50 years, it is unranked for now. However if this species is determined to be extant, it should be reassessed with consideration to rank it as imperiled due to its small range extent.. NatureServe Specific Text (NOT OTHERWISE INCLUDED IN ABOVE TEXT): For Rank Calculator: 1. Element occurrences (using separation distance of 5,000 m): 0 1. Estimated Number of Element Occurrences Comments: There are no element occurrences of this species from the last 30 years (since 1995). Overall , this species is known from just three occurrences using a 5 km separation distance. 2. Population size: Unknown 3. Viability/Ecological integrity (choose one) 1. Number of occurrences with good viability/ecological integrity: Unknown 2. Percent of area occupied (For Species with Known AOO): N/A 4. Environmental Specificity: B. Narrow. Specialist or community with key requirements common. 1. Environmental specificity comments: This species is a dietary specialist, using pollen from the plant genus Camissonia, which likely restricts its distribution and phenology. 5. Intrinsic Vulnerability: B. Moderately vulnerable 1. Intrinsic vulnerability comments: Andrena have been reported to have low reproductive output because of the short adult life span, and a low rate of brood cell provisioning (reviewed in Danforth et al. 2019). 6. Trend 1. Short Term Trend: Unknown 2. Comments: Abundance estimates and population trends are not known for this species. 3. Long Term Trend: Unknown 4. Comments: Abundance estimates and population trends are not known for this species. For Biotics Global Element Characterization: 1. Habitat Shrubland/chaparral 2. Food Habits 1. Adult: nectarivore 2. Immature: nectarivore Literature References: Brown, Mark J. F., and Robert J. Paxton. 2009. “The Conservation of Bees: A Global Perspective.” Apidologie 40 (3): 410–16. Cane, James H., and Byron G. Love. 2021. “Hygroscopic Larval Provisions of Bees Absorb Soil Water Vapor and Release Liquefied Nutrients.” Apidologie 52 (6): 1002–16. Cane, J. H. 1981. “Dufour’s Gland Secretion in the Cell Linings of Bees (Hymenoptera: Apoidea).” Journal of Chemical Ecology 7 (2): 403–10. Chesshire, Paige R., Erica E. Fischer, Nicolas J. Dowdy, Terry L. Griswold, Alice C. Hughes, Michael C. Orr, John S. Ascher, et al. 2023. “Completeness Analysis for over 3000 United States Bee Species Identifies Persistent Data Gap.” Ecography, February. https://doi.org/10.1111/ecog.06584. Danforth, Bryan N., Robert L. Minckley, John L. Neff, and Frances Fawcett. 2019. The Solitary Bees: Biology, Evolution, Conservation. Princeton University Press. Grab, Heather, Michael G. Branstetter, Nolan Amon, Katherine R. Urban-Mead, Mia G. Park, Jason Gibbs, Eleanor J. Blitzer, Katja Poveda, Greg Loeb, and Bryan N. Danforth. 2019. “Agriculturally Dominated Landscapes Reduce Bee Phylogenetic Diversity and Pollination Services.” Science 363 (6424): 282–84. LaBerge, Wallace E., and Robbin W. Thorp. 2005. “A Revision of the Bees of the Genus Andrena of the Western Hemisphere.” Illinois Natural History Survey Bulletin 37 (1-6): 1–64. Michener, Charles Duncan. 2007. The Bees of the World. Vol. 1. JHU Press. Packer, Laurence, Amro Zayed, Jennifer C. Grixti, Luisa Ruz, Robin E. Owen, Felipe Vivallo, and Haroldo Toro. 2005. “Conservation Genetics of Potentially Endangered Mutualisms: Reduced Levels of Genetic Variation in Specialist versus Generalist Bees.” Conservation Biology: The Journal of the Society for Conservation Biology 19 (1): 195–202. Potts, Simon G., Jacobus C. Biesmeijer, Claire Kremen, Peter Neumann, Oliver Schweiger, and William E. Kunin. 2010. “Global Pollinator Declines: Trends, Impacts and Drivers.” Trends in Ecology & Evolution 25 (6): 345–53. Raven, Peter H., and David L. Wagner. 2021. “Agricultural Intensification and Climate Change Are Rapidly Decreasing Insect Biodiversity.” Proceedings of the National Academy of Sciences of the United States of America 118 (2). https://doi.org/10.1073/pnas.2002548117. Roberts, Stuart, Simon Potts, Koos Biesmeijer, Michael Kuhlmann, William Kunin, and Ralf Ohlemüller. 2011. “Assessing Continental-Scale Risks for Generalist and Specialist Pollinating Bee Species under Climate Change.” BioRisk : Biodiversity & Ecosystem Risk Assessment 6 (December):1–18. Rousseau, Josée S., S. Hollis Woodard, Sarina Jepsen, Brianne Du Clos, Alison Johnston, Bryan N. Danforth, and Amanda D. Rodewald. 2024. “Advancing Bee Conservation in the US: Gaps and Opportunities in Data Collection and Reporting.” Frontiers in Ecology and Evolution 12. https://doi.org/10.3389/fevo.2024.1346795. Williams, A. Park, B. I. Cook, and S. E. Smerdon. 2022. “Rapid Intensification of the Emerging Southwestern North American Megadrought in 2020–2021.” Nature Climate Change 12 (3): 232–34. Williams, N. M., Elizabeth E. Crone, T’ai H. Roulston, Robert L. Minckley, Laurence Packer, and Simon G. Potts. 2010. “Ecological and Life-History Traits Predict Bee Species Responses to Environmental Disturbances.” Biological Conservation 143 (10): 2280–91. Wojcik, Victoria A., Lora A. Morandin, Laurie Davies Adams, and Kelly E. Rourke. 2018. “Floral Resource Competition Between Honey Bees and Wild Bees: Is There Clear Evidence and Can We Guide Management and Conservation?” Environmental Entomology 47 (4): 822–33.

Conservation needs No known conservation actions are in place for this species. Protected/Managed area comment: Observations of this species are known from Bureau of Land Management (BLM) land, but this does not confer any specific protections to the species. Management comment: Specific conservation needs for this species have not been identified. Due to the importance of supporting wild bee populations for pollination services, general conservation practices are recommended including, restoring, creating, and preserving natural high-quality habitats to include suitable forage and nesting sites; limiting pesticide use on or near suitable habitat, particularly during the adult bee’s flight period; promoting farming and urban practices that increase pollinator-friendly plants in margin space; minimizing exposure of wild bees to diseases transferred from managed bees; and lastly, avoiding honey bee introduction to high-quality native bee habitat.

Research need comment: More information is needed about the population status, population trend, existing threats, range limits, habitat, and ecology of this species. Surveys targeting this species are needed throughout its range to determine its persistence throughout its historic range.

This species is apparently distinct from Andrena mohavensis Ribble, 1974, although there may be some mislabeled specimens of either species based on similarity of names.