Andrena haynesi

Justification:
Haynes’ miner bee (Andrena haynesi) is a pollen specialist species known from the Great Plains region of the United States. Using all known observations of this species, the extent of occurrence is 2,119,340 km2. Although there are few recent observations of this species, these come from several widely distributed localities. Lack of recent observations may reflect limited survey effort through much of the Great Plains region and early time of day it is active. Although this species has a narrow dietary breadth, its host plant, Helianthus (Asteraceae), is typically abundant and widespread across many ecosystem types. Within the range of this species, major land use change, resulting in habitat fragmentation, loss, and degradation have occurred, coupled with increased use of pesticides. These threats may be acting on the species at a local scale. More research is needed to describe population trends and to determine the species’s persistence throughout its entire range. Because this species is widespread and occurs in many different ecoregions, it is unlikely that it is threatened with extinction at this time. As such, it is assessed as Least Concern.

Andrena haynesi appears to be a narrow pollen specialist bee of the sunflower genus Helianthus, although some records are from other genera within Asteraceae (LaBerge 1967). This bee is recorded from grasslands, shrublands, including the Sand Hills, Great Plains, and High Plains, as well as sand deserts of the Colorado Plateau (Chesshire et al. 2023). This species has been observed foraging during the coolest part of the day between 6 am and 9:30 am. This species nests underground, and has one of the deepest nests recorded for any recorded temperate zone bee, excavating burrows in sand nearly 3 m deep (Parker and Griswold 1982). The entrance of the nests of this species are marked by a steep-sided cone shaped mound, or tumulus, made of sand and soil excavated from the nest. These tumuli are larger than those made by most other mining bees. In the only described nest of this species, a single horizontal cell was recorded at the end of the burrow, and was lined with a waxy Dufour’s gland secretion (Parker and Griswold 1982) 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). When females are not actively foraging, they plug nest entrances with moistened soil (Parker and Griswold 1982). Females provision each cell with a ball of pollen moistened with nectar before on which they lay a single egg (Michener 2007). This species overwinters as last instar larvae, as opposed to as pupae, which is more common (Neff and Simpson 1997). The presence of a parasitic bee (Nomada) has been recorded in the nest of A. haynesi (Parker and Griswold 1982). Records of this species come from August and September (Parker and Griswold 1982; Chesshire et al. 2023). Adults are assumed to emerge annually (Danforth et al. 2019). Habitat:

Specific threats to this species are not well understood. However, the native grasslands where this bee occurs have seen major impacts due to agricultural intensification and expansion (Foley et al. 2005). These changes have resulted in a loss of intact prairie ecosystems, as well as a decline in overall habitat quality (F. Samson and Knopf 1994; F. B. Samson, Knopf, and Ostlie 2004; Otto et al. 2018). Land use conversion to agriculture also comes with increased pesticide exposure for Haynes’ miner bee, which may contribute to serious risk for this species. Although the dietary needs of this species may be met by sunflower (Helianthus) farming, the associated risks of pesticide exposure and nest site disturbance through tillings may contribute to overall habitat unsuitability for the species. Certain aspects of this species' biology may make it more vulnerable to some threats. Andrena haynesi 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 narrow 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, and 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.

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