Andrena barbara

Justification:
Barbara’s Miner Bee (Andrena barbara) is a dietary generalist solitary bee that occurs in the eastern United States. Using all observations, the extent of occurrence is 2,079,085 km2, and observations from the last decade are relatively well distributed throughout the entire known range of the species. This species has been observed in grasslands, pasturelands, forests, urban areas, and agricultural areas, and plays an important role in apple production. Across the range of the species, impacts from habitat loss and modification, climate change, and exposure to pesticides has been observed. These threats may be acting on the species at local levels. However, because the species is widespread, occurs in many habitat types, and has been recently observed across much of its range, it is unlikely that it is threatened with extinction at this time. As such, it is assessed as Least Concern for now.

Barbara’s Miner Bee is a dietary generalist species that appears to prefer foraging spring flowering trees and shrubs including Prunus, Pyrus, Crataegus, and Salix (Bouseman and LaBerge 1978). It has also been recorded foraging on early flowering forbs, including Brassica, Camassia, Erythronium, and Taraxacum (Bouseman and LaBerge 1978). This species makes up a large percentage of overall pollinators in apples, suggesting it may play an important role in this crop’s pollination (Adamson et al. 2012). This species has been recorded from grasslands, pasturelands, evergreen and deciduous forests, agricultural and urban areas. 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 to June, with most records from March through May(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 barbara 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). This species has had its conservation status evaluated using NatureServe criteria at the U.S. state and Canadian province level in some areas where it occurs. This species has been evaluated as Vulnerable in New York.

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