Andrena berberidis

Justification:
This narrative text will summarize all of the previous sections and outline the evidence for determining which Red List Category a species qualifies for, and which criteria were used to make this designation. Red List Categories include LC (Least Concern), NT (Near Threatened), VU (Vulnerable), EN (Endangered), CR (Critically Endangered), DD (Data Deficient), EX (Extinct), and EW (Extinct in the Wild). Red List Criteria include A (population size reduction), B (limited geographic range and severe fragmentation, continuing declines or fluctuation), C (small population size and decline, D (very small or restricted populations), E (quantitative analysis).

Andrena berberidis has been most commonly collected from plants in the family Berberidaceae, including the genera Berberis and Mahonia. It has also been collected from Potentilla (Rosaceae) (LaBerge 1985). There are too few records to determine the dietary breadth of this species. It has been recorded from evergreen and deciduous forest, shrubland, grassland, urban environmentsThis 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 March through June (Chesshire et al. 2023). Adults are assumed to emerge annually (Danforth et al. 2019). This species hosts a recently described species of strepsipteran parasite, Stylops piercei (Zabinski and Cook 2023), but rates of parasitism or impacts on fitness have not been described.

Although there are limited locations of this species, apparently few have measurable threats impacting them. Two locations are in close proximity to agricultural lands, where they may be subject to threats associated with exposure to pesticides. Certain aspects of this species' biology may make it more vulnerable to some threats. Andrena berberidis 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 may be 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).

Conservation needs No known conservation actions are in place for this species. Observations of this species are known from Bureau of Land Management (BLM) and United States Forest 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.