Pollen-specialist
Guides
Andrena rehni
Rehn's Miner Bee
Andrena rehni is a solitary, ground-nesting miner bee native to eastern North America. The species is oligolectic, specializing on pollen from Castanea species including American chestnut and Allegheny chinkapin. Following the functional extinction of American chestnut due to chestnut blight, the bee became increasingly rare and was not documented for nearly a century until its rediscovery in 2018. It has since been recorded in multiple states after long absences.
Chelostoma
Scissor Bees
Chelostoma is a genus of solitary bees in the tribe Osmiini (family Megachilidae), comprising approximately 56-60 described species across five subgenera. These bees are predominantly Palaearctic in distribution and are notable for their high degree of pollen specialization: most species are strict oligoleges, collecting pollen from flowers of a single plant genus, subfamily, or family. Common host plant associations include Campanula (bellflowers), Ornithogalum, Ranunculus, Asteraceae, and Brassicaceae. Nesting occurs in preexisting cavities in dead wood or hollow plant stems, with females constructing brood cell partitions and nest plugs using mud often reinforced with pebbles and sand grains.
Diadasia
cactus bees, bindweed turret bees
Diadasia is a genus of solitary bees in the family Apidae, tribe Emphorini, containing approximately 42 species. These bees are oligolectic pollen specialists that primarily forage on plants in the family Malvaceae, though some species have evolved associations with other plant groups including cacti, bindweeds, and willowherbs. They are ground-nesting bees, with many species constructing distinctive turrets or chimney-like structures at their nest entrances. Male Diadasia form large mating aggregations where they compete intensely for access to emerging females.
Diadasia bituberculata
Bindweed Turret Bee, Bindweed Bee, Digger Bee, Chimney Bee
Diadasia bituberculata is a solitary ground-nesting bee in the family Apidae, commonly known as the bindweed turret bee. It is native to the western coast of North America, with its range extending from Oregon through California to Baja California, Mexico. The species is an obligate specialist pollinator of bindweed (morning glory), foraging almost exclusively on plants in the genus Convolvulus. Females construct distinctive soil turrets at nest entrances in flat, bare ground, provisioning underground cells with pollen for their offspring.
Diadasia laticauda
Diadasia laticauda is a solitary bee species in the family Apidae, described by Cockerell in 1905. It belongs to the genus Diadasia, which comprises ground-nesting bees commonly known as cactus bees due to their specialized association with cactus pollen. Like other members of its genus, D. laticauda is likely a pollen specialist, though specific host plant associations for this species remain poorly documented. The species is native to North America.
Diadasia nigrifrons
Black-fronted turret bee
Diadasia nigrifrons is a species of solitary bee in the family Apidae, commonly known as the black-fronted turret bee. Like other members of the genus Diadasia, it is a ground-nesting bee that constructs distinctive turrets at its nest entrance. The species is native to North America and is part of a diverse genus of bees that specialize on particular host plants for pollen collection.
Diadasia ochracea
Ochraceous Chimney Bee
Diadasia ochracea, commonly known as the ochraceous chimney bee, is a solitary ground-nesting bee in the family Apidae. The species is distributed across Central America and North America. As a member of the genus Diadasia, it is likely a pollen specialist, though specific host plants for this species are not documented in available sources.
Dieunomia
Dieunomia is a genus of sweat bees in the family Halictidae, containing approximately nine described species. These bees are among the largest in their family, second only to the genus Nomia. They are relatively uncommon and exhibit specialized ecological relationships with their pollen sources.
Dieunomia bolliana
Dieunomia bolliana is a species of sweat bee in the family Halictidae, subfamily Nomiinae. It was originally described as Nomia bolliana by Cockerell in 1910 and later transferred to the genus Dieunomia. The genus Dieunomia comprises medium to large bees that are often associated with wetland habitats and are known to be pollen specialists on certain plant families. Records indicate presence in North America, though detailed biological information remains limited.
Hesperapis oraria
Gulf Coast solitary bee, Gulf Coast evening bee
Hesperapis oraria is a rare, solitary bee endemic to the northern Gulf Coast of the United States. Described in 1997, it is the only known member of the subfamily Dasypodainae in eastern North America. The species is monolectic, relying exclusively on the coastal plain honeycomb head (Balduina angustifolia) for pollen and nectar. It is critically imperiled due to its restricted range and habitat specificity.
Lasioglossum texanum
Nocturnal Sweat Bee, Texas Sweat Bee
Lasioglossum texanum is a nocturnal sweat bee (family Halictidae) notable for its unusual foraging behavior. Unlike most bees, it actively collects pollen during evening hours and continues after dark until approximately 10:00 PM when moonlight is available. It is a ground-nesting solitary bee with highly specialized pollen preferences, foraging exclusively from flowers of the four-point evening-primrose (Oenothera rhombipetala).