Andrena asteroides

Justification:
Andrena asteroides is a pollen specialist solitary bee that visits plants from the family Asteraceae for pollen. It occurs in the eastern United States, from Mississippi east to Florida, and north to New Jersey. Using all high quality records of the species, the extent of occurrence is 706,045 km2. The species has been recorded in at least five localities since 2013, which are relatively well distributed across the EOO of the species. Andrena asteroides has been recorded in several forest types, as well as agricultural and urban areas. Across the range of the species, impacts from climate change, urbanization, and exposure to pesticides have been observed. These threats may be acting on the species at local levels. More information is needed to determine the population trend and establish a better understanding of range limits and the life history of the species. Based on analysis using approximately 30 data points, this species does appear to be at risk of extinction at this time. As such, it is evaluated as Least Concern. However, as there are at least 120 additional specimens of this species used in the species revision that were not available as digitized specimen records at the time of the assessment, this species should be re-evaluated as more data become available.

Andrena asteroides is a dietary specialist that visits plants from the family Asteraceae for pollen (LaBerge 1967). This species has been recorded visiting the federally endangered Whorled Sunflower (Helianthus verticillatus) where it occurs in Georgia. The bee may warrant some conservation attention based on its visitation to this self-incompatible imperiled sunflower. Andrena asteroides has been recorded from deciduous, evergreen, and mixed forest, agricultural and urban areasThis 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 September through November, with most records from October (LaBerge 1967; Chesshire et al. 2023). Adults are assumed to emerge annually (Danforth et al. 2019).

Certain aspects of this species' biology may make it more vulnerable to some threats. Andrena asteroides 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).

Conservation needs No known conservation actions are in place for this species. Observations of this species are known from United States Forest Service 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.