Oligolectic
Guides
Ptilothrix
chimney bees, mallow bees
Ptilothrix is a genus of solitary, ground-nesting bees in the family Apidae, tribe Emphorini, with an amphitropical distribution in the New World. These bees range from 7 to 15 mm in body length and are distinguished by prominent, coarse scopae on their hind legs adapted for collecting large-grained pollen. Females excavate nests in hard-packed soil using water carried from ponds to moisten the substrate, constructing distinctive turreted or chimney-like nest entrances. The genus exhibits narrow pollen specialization (oligolecty), with species specializing on particular plant families including Malvaceae, Convolvulaceae, Onagraceae, Cactaceae, Pontederiaceae, and Asteraceae.
Ptilothrix bombiformis
Hibiscus bee, Eastern digger bee, Hibiscus turret bee
Ptilothrix bombiformis is a solitary ground-nesting bee in the family Apidae, commonly known as the hibiscus bee or eastern digger bee. It is one of only two species of the genus Ptilothrix found in the United States, with a distribution centered in the eastern half of North America. The species is notable for its specialized association with mallow family plants (Malvaceae), particularly Hibiscus species, and for its distinctive nesting behavior involving water transport to excavate hard soil. Females construct turreted nest entrances and are active primarily during summer months when host plants are in bloom.
Ptilothrix chiricahua
Ptilothrix chiricahua is a solitary ground-nesting bee described in 2023 from specimens collected in the Chihuahuan Desert. It is a specialist pollinator of Kallstroemia grandiflora, with flight activity synchronized to this host's late summer bloom. The species exhibits the distinctive water-walking behavior characteristic of its genus, using surface tension to retrieve water for nest excavation. It was previously misidentified as Ptilothrix sumichrasti until taxonomic revision split that species into three distinct taxa.
Trachusa larreae
Trachusa larreae is a solitary bee in the family Megachilidae, tribe Anthidiini. It is an oligolectic specialist pollinator of Larrea tridentata (creosote bush), with documented nesting biology and immature stages. The species occurs in arid regions of North and Central America where its host plant is present.
Xenoglossa
Squash Bees and Allies, Squash Bees
Xenoglossa is a genus of large bees in the family Apidae, commonly known as squash bees. Species in this genus are oligolectic pollen specialists, with most species foraging exclusively on Cucurbita crops (Cucurbitaceae). Some species, such as X. (Cemolobus) ipomoeae, specialize on Ipomoea (Convolvulaceae) instead. These solitary, ground-nesting bees are native to North America and are important agricultural pollinators. Adults are active for a brief period in summer, coinciding with host plant bloom.
Xenoglossa angustior
Red-tailed Squash Bee
Xenoglossa angustior, the Red-tailed Squash Bee, is a specialist pollinator of cucurbits (Cucurbitaceae) in the tribe Eucerini. It is native to North and Middle America and shares the common name "squash bee" with the related genus Peponapis. Both genera are oligoleges that pollinate exclusively squash, pumpkins, gourds, cucumbers, and zucchini.
Xenoglossa kansensis
Kansas squash bee
Xenoglossa kansensis, commonly known as the Kansas squash bee, is a solitary long-horned bee in the family Apidae. It belongs to a genus of specialist pollinators that are oligoleges on cucurbits (the squash family, Cucurbitaceae). The species is native to North America and is one of two related genera (Xenoglossa and Peponapis) commonly referred to as squash bees. Like other squash bees, it is an early-morning pollinator of cucurbit crops.
Xenoglossa strenua
Nimble Squash Bee
Xenoglossa strenua is a species of long-horned bee in the family Apidae, native to North and Central America. It is an oligolectic pollinator specialized on the cucurbit family (Cucurbitaceae), including pumpkins, squash, gourds, cucumbers, and zucchini. The species is active early in the morning, visiting flowers as soon as they open, before most other bee species begin foraging.
Xenoglossodes
Xenoglossodes is a subgenus of long-horned bees in the genus Xenoglossa (family Apidae). Established by Ashmead in 1899, it is currently recognized as a subgenus rather than a full genus. The taxonomic status has been historically unstable, with Xenoglossodes excurrens (Cockerell, 1903) now treated as a synonym of Melissodes subagilis. Members are specialist bees associated with cucurbit flowers.