Andrena auricoma

Justification:
The Golden-haired Miner Bee is a dietary generalist solitary bee that occurs primarily in the United States, with observations also from the extreme southwest of Canada, and the extreme north of Mexico. Using all records of the species, the extent of occurrence is 2,033,958 km2. Recent observations are relatively well distributed across the range of the species, although are restricted to the western part of the range. There are no recent observations from the Intermountain West region. Across the range of the species, impacts from habitat destruction, fragmentation, and modification have been observed. Additional impacts from pesticide exposure, and climate change may be acting on the species at local levels. More information is needed to assess the impact of these threats, and to track a population trend for this species. However, because the species is widespread, occurs across many habitat types, and is known from widely dispersed recent records, it is unlikely that it is threatened with extinction at this time. As such it is assessed as Least Concern.

The Golden-haired Mining Bee has been described as a dietary generalist, with the most common floral associations from the genera Ranunculus, Salix, Potentilla, and Descurainia (Laberge and Ribble 1975). However, in one study from British Columbia, Canada on the pollen preferences of this bee showed females were primarily collected from plants in the family Apiaceae, and that pollen from this family was the dominant pollen type in pollen loads. It has also been recorded foraging at Lomatium (Apiaceae) in the Intermountain West (Cane, Weber, and Love 2020). This suggests that foraging preferences may be context dependent. This species has been recorded in shrublands, temperate and desert grasslands, evergreen forests, agricultural areas, and urban areas, including at five different farms in the Brentwood, CA area (Frankie et al. 2019) 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). Records of this species come from February through August, with most records from April and May (Chesshire et al. 2023). Adults are assumed to emerge annually (Danforth et al. 2019).

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). Many observations of this species come from California coastal sage scrub habitat, one of California's most threatened vegetation types, which is globally imperiled (NatureServe 2024). This habitat is highly threatened by modification, fragmentation, and loss due to urban and suburban growth. Nearly half of California’s residents live in the coastal California counties where this habitat occurs, which is less than 10% of the state’s land area (Riordan and Rundel 2013). Less than 20% of this habitat remains (Davis, Stine, and Stoms 1994), and the existing fragments are considered some of most valuable real estate in California. This contributes to considerable development pressure on remaining fragments, and their high real estate value makes their conservation costly. Coastal sage scrub has also been modified significantly in the past 100 years due to exotic annual grass invasion, which has been facilitated by increased wildfire frequency (Minnich and Dezzani 1998; Talluto and Suding 2008). These factors also contribute to a feedback where increased grass cover increases fire frequency, leading to grassland conversion. This habitat conversion may limit the availability of host plants used by Andrena auricoma and alter other abiotic factors important for this species. Certain aspects of this species' biology may make it more vulnerable to some threats. Andrena auricoma 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).

Conservation needs No known conservation actions are in place for this species. Observations of this species are known from Bureau of Land Management (BLM), United States Forest Service, United States Fish and Wildlife, and National Park Service land, but this does not confer any specific protections to the species. Further research is needed to determine the overall size of the population and to identify trends and existing threats. 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.

Surveys targeting this species are needed throughout its range to determine its persistence throughout its historic range. More information is needed about the population status, range limits, habitat, and ecology of this species.

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