Andrena dissona

Justification:
Andrena dissona is a solitary bee that occurs in the Central Valley of California. The species is only known from 10 observations and just six localities. Using all observations of the species, the extent of occurrence is 12,490 km2. However, this species has not been observed since 1969. It is unclear if the species is extant. There is little available information about the habitat and ecology of the species. It has been observed in grasslands and agricultural areas. This species may be impacted by agricultural conversion, which has likely influenced the quality and quantity of available food plants for this species. It also occurs in California’s Central Valley, which sees the nation’s highest pesticide inputs. It is inferred that these threats contribute to the continuing decline in the quality of the habitat of this species. More information is needed to determine if this species is still extant and to understand best ways to mitigate threats to the species. Because this species has a restricted extent of occurrence, is known from limited locations, and is inferred to have a decline in the quality of its habitat, it is assessed as Vulnerable under Babiii.

Food habits comment: There is little available information about the habitat and ecology of Andrena dissona. It has been recorded foraging from the genera Layia and Baeria (Asteraceae), but there is not enough available information to determine its dietary breadth. Habitat comment: This species has been recorded in grassland and agricultural areas, at low elevations. Reproduction comment: This species likely nests underground like all other Andrena (Danforth et al. 2019), but nests from this species have not been described. 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).

Threat comments: Specific threats to this species have not been investigated. This species may be impacted by drought, which has been ongoing in this species’ range. Since 2000, the Southwest U.S. has seen the worst drought in 1200 years (Williams, Cook, and Smerdon 2022). Drought can reduce the abundance of flowering plants on a landscape scale, and also reduce pollen and nectar quality (Wilson Rankin, Barney, and Lozano 2020). Drought conditions have been shown to reduce the diversity and abundance of native bees (Minckley, Roulston, and Williams 2013; Hung et al. 2021). This species may be impacted by agricultural intensification, including high exposure to pesticides where it occurs in California’s Central Valley. The Central Valley of California is one of the most intensively farmed regions in the U.S.(Katibah 1984). An estimated 71% of the Central California Valley ecoregion is devoted to agriculture (Soulard and Wilson 2015). This species may be impacted by high exposure to pesticides where it occurs in the Central Valley. This region has some of the nation’s highest pesticide inputs, which can be detected in non-target plant species, sometimes in insect-lethal concentrations, across all land use types (Halsch et al. 2020). Certain aspects of this species' biology may make it more vulnerable to some threats. Andrena dissona 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). 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: 2. Agriculture & aquaculture -> 2.1. Annual & perennial non-timber crops -> 2.1.3. Agro-industry farming Timing: Ongoing Scope: Majority (50-90%) Severity: Slow, significant declines 8. Invasive and other problematic species, genes, and diseases -> 8.1 Invasive non-native/alien species/diseases -> 8.1.2. Named species Timing: Ongoing Scope: Majority (50-90%) Severity: Slow, significant declines 9. Pollution -> 9.3 Agricultural and forestry effluents -> 9.3.3 Herbicides and Pesticides Timing: Ongoing Scope: Majority (50-90%) Severity: Slow, significant declines 11. Climate change & severe weather -> 11.1. Habitat shifting & alteration Timing: Ongoing Scope: Majority (50-90%) Severity: Slow, significant declines 11. Climate change & severe weather -> 11.2.Droughts Timing: Ongoing Scope: Majority (50-90%) Severity: Slow, significant declines 11. Climate change & severe weather -> 11.3.Temperature extremes Timing: Ongoing Scope: Majority (50-90%) Severity: Slow, significant declines Conservation Actions Conservation needs No known conservation actions are in place for this species. Protected/Managed area comment: There are no observations of this species from federally protected land. 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): Assessors names (use * to indicate primary assessor, typically the participant with most experience/knowledge of the species): 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: Vulnerable Babiii Justification: Andrena dissona is a solitary bee that occurs in the Central Valley of California. The species is only known from 10 observations and just six localities. Using all observations of the species, the extent of occurrence is 12,490 km2. However, this species has not been observed since 1969. It is unclear if the species is extant. There is little available information about the habitat and ecology of the species. It has been observed in grasslands and agricultural areas. This species may be impacted by agricultural conversion, which has likely influenced the quality and quantity of available food plants for this species. It also occurs in California’s Central Valley, which sees the nation’s highest pesticide inputs. It is inferred that these threats contribute to the continuing decline in the quality of the habitat of this species. More information is needed to determine if this species is still extant and to understand best ways to mitigate threats to the species. Because this species has a restricted extent of occurrence, is known from limited locations, and is inferred to have a decline in the quality of its habitat, it is assessed as Vulnerable under Babiii. Rank reasons This species is a solitary bee that occurs in the Central Valley of California. Using all verified records of the species, the range extent is 12,490 km2, but has not been observed anywhere it its range since 1969. This species occurs in grassland and agricultural areas. This species has been observed foraging from two genera from the plant family Asteraceae, but there is not enough information about it to determine its dietary breadth. This species faces threats from habitat loss and degradation due to agricultural practices, and occurs in a region that sees the nation’s highest pesticide inputs. Pesticides may be causing lethal and sublethal impacts for the species. Because this species is known from a small range extent, few localities overall, and sees threats from habitat loss and pesticide exposure, it is likely to be threatened with extinction at this time. 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: Using all records from the last 30 years (since 1995), this species is known from zero 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: A. Unknown. 1. Environmental specificity comments: There is not enough information about habitat and ecology of this species to understand its environmental specificity, but it may have habitat requirements that are not yet understood. 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 Grassland/Herbaceous, Cropland/Hedgerow 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. Halsch, Christopher A., Aimee Code, Sarah M. Hoyle, James A. Fordyce, Nicolas Baert, and Matthew L. Forister. 2020. “Pesticide Contamination of Milkweeds Across the Agricultural, Urban, and Open Spaces of Low-Elevation Northern California.” Frontiers in Ecology and Evolution 8:162. Hung, Keng-Lou James, Sara S. Sandoval, John S. Ascher, and David A. Holway. 2021. “Joint Impacts of Drought and Habitat Fragmentation on Native Bee Assemblages in a California Biodiversity Hotspot.” Insects 12 (2). https://doi.org/10.3390/insects12020135. Katibah, Edwin F. 1984. “A Brief History of Riparian Forests in the Central Valley of California[l].” Press, c 1:984. 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. Minckley, Robert L., T’ai H. Roulston, and Neal M. Williams. 2013. “Resource Assurance Predicts Specialist and Generalist Bee Activity in Drought.” Proceedings. Biological Sciences / The Royal Society 280 (1759): 20122703. 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. 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. Soulard, Christopher E., and Tamara S. Wilson. 2015. “Recent Land-Use/land-Cover Change in the Central California Valley.” Journal of Land Use Science 10 (1): 59–80. 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. Wilson Rankin, Erin E., Sarah K. Barney, and Giselle E. Lozano. 2020. “Reduced Water Negatively Impacts Social Bee Survival and Productivity Via Shifts in Floral Nutrition.” Journal of Insect Science 20 (5). https://doi.org/10.1093/jisesa/ieaa114. 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: There are no observations of this species from federally protected land. 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.

(a. any taxonomic concerns about the validity of the species? b. any taxonomic revisions underway that would require a species reassessment.