Andrena macoupinensis

Justification:
The Macoupin County miner bee is a pollen specialist bee that occurs across much of the United States, and into Southeast Canada. Using all known records of the species, the extent of occurrence is 7,090,521 km2. There are limited recent records for this species throughout its entire range, although it has been detected in small numbers in several recent bee fauna surveys in widely dispersed study sites. Recent records are especially limited in the western half of its range, although it has been detected where comprehensive survey efforts have been conducted. Thus, lack of recent records may be due to limited recent search effort. Across its range, impacts from land use change, climate change, and pesticides have been reported, so threats may be acting on this species at a local level. However, because this species is widespread and occurs in many different habitat types, it is unlikely to be threatened with extinction at this time. As such, it is assessed as Least Concern for now.

Macoupin County miner bee is a pollen specialist bee on pollen from the genus Salix (Salicaceae). The species occurs across a broad range of habitat types, including the central basin and range of US western cold and warm deserts, montane forests of the Sierra Nevada, the Great Plains, and the Southeastern Plains, 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 March through September, with the majority of the records from April and 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 macoupinensis 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 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). 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, 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 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.

(a. any taxonomic concerns about the validity of the species? b. any taxonomic revisions underway that would require a species reassessment.