Andrena jessicae

Justification:
Jessica’s mining bee (Andrena jessicae) is a pollen specialist, spring-active bee species that specializes on pollen from the plant genus Physaria (Brassicaceae). The species occurs in the southwest United States and northern Mexico. Using all known records, the extent of occurrence (EOO) is 1,010,597 km2. Records since 2013 come from southeast Arizona and several localities in Texas. Across the range of the species, climate change impacts and land use change have been observed, so it is possible that these threats are acting on the species at a local level. Because the species has a narrow dietary breadth on a plant with limited flowering in drought years, this species may be particularly impacted by drought. Because this species is widespread and occurs in several different habitats, it is not likely threatened with extinction at this time. As such it is assessed as Least Concern.

Based on floral associates from a limited number of records, Jessica’s mining bee is presumed to be a pollen specialist, using the plant genus Physaria (Brassicaceae) (Laberge and Bouseman 1970). It has been recorded from the Sonoran, Mojave, and Chihuahuan deserts, as well as the southern Great Plains, and Madrean woodlands. 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, (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 and April (Laberge and Bouseman 1970; Chesshire et al. 2023). Adults are assumed to emerge annually (Danforth et al. 2019).

Specific threats have not been identified for this species. However, since 2000, the Southwest U.S. has seen the worst drought in 1200 years (A. P. 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 (Hung et al. 2021). Because Jessica’s mining bee has a short adult life stage, emerges in spring, and appears to be a narrow pollen specialist of the plant genus Physaria, which blooms in response to winter rain, it may be at further risk from winter droughts within its range. Certain aspects of this species' biology may make it more vulnerable to some threats. Jessica’s mining bee 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 (N. M. Williams et al. 2010). This species is oligolectic, 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). The narrow dietary breadth (apparently within the genus Physaria) of Jessica’s mining bee may make it particularly susceptible to climate change, as its host plant can have significantly reduced floral abundance in drought years, which are becoming increasingly common with its range (Minckley, Roulston, and Williams 2013). 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).

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 Land, and United States Fish and Wildlife 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 better understand 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.

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.