Andrena ceanothi

Justification:
Andrena ceanothi is a solitary bee that occurs in the north eastern quadrant of the United States and likely in southern Canada as well. Using all observations, the extent of occurrence is 2,722,671 km2. Records since 2014 are relatively well distributed across the range of the species. The species is likely a dietary generalist, collecting pollen from a wide range of plant families to provision nests for offspring. Andrena ceanothi has been observed in forests, agricultural areas, and urban areas. Across the range of the species, impacts from habitat loss and degradation, climate change, and exposure to pesticides have been observed. These threats are likely acting on the species at local levels. More information is needed to determine a population trend and to assess the degree to which these threats act on populations. However, because this species is widespread, occurs in many different habitat types, forages from a wide range of plants, and has been described as common in some areas, it is unlikely that it is threatened with extinction at this time. As such, it is assessed as Least Concern. Andrena

Andrena ceanothi has been reported as a dietary specialist of the plant genus Vaccinium (Ericaceae) (Goldstein and Ascher 2016), although the pollen loads from the species contained pollen from a wide range of plant families in another study (Wood and Roberts 2018). These pollen loads contained pollen from the plant families Rosaceae, Rhamnaceae, Anacardiaceae, Salicaceae, Cornaceae, and Aquifoliaceae (Wood and Roberts 2018). Andrena ceanothi has been observed in grasslands, pasturelands, evergreen, deciduous, and mixed forest, 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 April through July, with most records from May and June (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 ceanothi 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). If this species is a dietary specialist, it may be 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 National Park Service, United States Fish and Wildlife, 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.