Members of the family Megachilidae are commonly known as leafcutting bees, mason bees, and resin bees. Eighty-one (81) species of megachilid bees have been recorded in Pennsylvania [1]. Of these species, 14 (Anthidium manicatum, Anthidium oblongatum, Chelostoma rapunculi, Coelioxys coturnix, Hoplitis anthocopoides, Lithurgus chrysurus, Megachile apicalis, Megachile pusilla, Megachile rotundata – the alfalfa leafcutting bee, Megachile sculpturalis, Osmia caerulescens, Osmia cornifrons, Osmia taurus, and Pseudoanthidium nanum) are not native to North America (indicated by an asterisk; *). Worldwide, this family has over 4,110 species described [2].

General identifying morphological characters include:
- Two submarginal cells on the forewing
- Long tongue length
- Small to large size
- Wide range of colors and patterns, but may appear wasp-like, nearly hairless, and often have black, brown, or metallic coloration (green, bronze, blue)
- Females of non-parasitic species have hairs on the underside of their abdomen for carrying pollen
Nesting habitats
Bees in this family typically nest in tunnels that they either find or construct in wood. They will also use hollow twigs/stems, and other small cavities such as those in pine cones and snail shells. Bits of leaves, flower petals, mud, and/or plant resins are used to seal nests.
Sociality
All species in this family are solitary, but the females of some species may nest close together. When multiple nests are located in the same area, this is called an aggregation.
Other behavioral or biological traits
Megachilidae is one of the most diverse bee families in terms, of behavior and biological traits. Even closely related species or groups of species can be very different! Notably, some species are specialists that only collect pollen from certain plant species, while others are broad generalists that collect pollen from many different types of plants. Most bees in this family store food for their young in their own nests, but others are social parasites or cleptoparasites. Parasitic bees invade and lay their eggs in the nest of another bee species. Either the adult parasite or their larva kills the host’s young in the nest. Then, the parasite’s larva eats the food that the host stored. In this way, social parasites and cleptoparasites take advantage of the other species’ efforts to build a nest and collect food.
Species list
A checklist of megachilid bees recorded in Pennsylvania is presented below. For each species, we list the counties, date ranges, and the most recent years they have been collected or observed in the openly-accessible checklist [see 1].
Genus Anthidiellum — 1 species
Anthidiellum (Loyolanthidium) notatum notatum (Latreille, 1809)
Genus Anthidium — 2 species
Anthidium (Anthidium) manicatum manicatum (L., 1758) *
Anthidium (Proanthidium) oblongatum oblongatum (Illiger, 1806) *
Genus Chelostoma — 2 species
Chelostoma (Gyrodromella) rapunculi (Lepeletier, 1841) *
Chelostoma (Prochelostoma) philadelphi (Robertson, 1891)
Genus Coelioxys — 12 species
Coelioxys (Allocoelioxys) coturnix Pérez, 1884 *
Coelioxys (Boreocoelioxys) banksi Crawford, 1914
Coelioxys (Boreocoelioxys) moestus Cresson, 1864
Coelioxys (Boreocoelioxys) octodentatus Say, 1824
Coelioxys (Boreocoelioxys) porterae Cockerell, 1900
Coelioxys (Boreocoelioxys) rufitarsis Smith, 1854
Coelioxys (Boreocoelioxys) sayi Robertson, 1897
Coelioxys (Cyrtocoelioxys) modestus Smith, 1854
Coelioxys (Paracoelioxys) funerarius Smith, 1854
Coelioxys (Synocoelioxys) alternatus Say, 1837
Coelioxys (Synocoelioxys) hunteri Crawford, 1914
Coelioxys (Xerocoelioxys) immaculatus Cockerell, 1912
Genus Heriades — 3 species
Heriades (Neotrypetes) carinata Cresson, 1864
Heriades (Neotrypetes) leavitti Crawford, 1913
Heriades (Neotrypetes) variolosa (Cresson, 1872)
Genus Hoplitis — 7 species
Hoplitis (Alcidamea) pilosifrons (Cresson, 1864)
Hoplitis (Alcidamea) producta producta (Cresson, 1864)
Hoplitis (Alcidamea) truncata truncata (Cresson, 1878)
Hoplitis (Alcidamea) albifrons albifrons (Kirby, 1837)
Hoplitis (Alcidamea) spoliata (Provancher, 1888)
Hoplitis (Hoplitis) anthocopoides (Schrenk, 1853) *
Hoplitis (Robertsonella) simplex (Cresson, 1864)
Genus Lithurgus — 1 species
Lithurgus chrysurus Fonscolombe, 1834 *
Genus Megachile — 25 species
Megachile (Callomegachile) sculpturalis Smith, 1853 *
Megachile (Chelostomoides) campanulae (Robertson, 1903)
Megachile (Chelostomoides) exilis Cresson, 1872
Megachile (Eutricharaea) apicalis Spinola, 1808 *
Megachile (Eutricharaea) pusilla Pérez, 1884 *
Megachile (Eutricharaea) rotundata (F., 1787) *
Megachile (Leptorachis) petulans Cresson, 1878
Megachile (Litomegachile) brevis Say, 1837
Megachile (Litomegachile) mendica Cresson, 1878
Megachile (Litomegachile) texana Cresson, 1878
Megachile (Megachile) centuncularis (L., 1758)
Megachile (Megachile) inermis Provancher, 1888
Megachile (Megachile) montivaga Cresson, 1878
Megachile (Megachile) relativa Cresson, 1878
Megachile (Megachilodes) integra Cresson, 1878
Megachile (Sayapis) frugalis frugalis Cresson, 1872
Megachile (Sayapis) inimica sayi Cresson, 1878
Megachile (Sayapis) pugnata pugnata Say, 1837
Megachile (Xanthosarus) addenda Cresson, 1878
Megachile (Xanthosarus) frigida frigida Smith, 1853
Megachile (Xanthosarus) gemula gemula Cresson, 1878
Megachile (Xanthosarus) ingenua Cresson, 1878
Megachile (Xanthosarus) latimanus Say, 1823
Megachile (Xanthosarus) melanophaea melanophaea Smith, 1853
Megachile (Xanthosarus) mucida Cresson, 1878
Genus Osmia — 21 species
Osmia (Diceratosmia) conjuncta Cresson, 1864
Osmia (Helicosmia) caerulescens (L., 1758) *
Osmia (Helicosmia) chalybea Smith, 1853
Osmia (Helicosmia) coloradensis Cresson, 1878
Osmia (Helicosmia) georgica Cresson, 1878
Osmia (Helicosmia) texana Cresson, 1872
Osmia (Melanosmia) albiventris Cresson, 1864
Osmia (Melanosmia) atriventris Cresson, 1864
Osmia (Melanosmia) bucephala Cresson, 1864
Osmia (Melanosmia) collinsiae Robertson, 1905
Osmia (Melanosmia) distincta Cresson, 1864
Osmia (Melanosmia) felti Cockerell, 1911
Osmia (Melanosmia) inspergens Lovell & Cockerell, 1907
Osmia (Melanosmia) proxima Cresson, 1864
Osmia (Melanosmia) pumila Cresson, 1864
Osmia (Melanosmia) sandhouseae Mitchell, 1927
Osmia (Melanosmia) simillima Smith, 1853
Osmia (Melanosmia) virga Sandhouse, 1939
Osmia (Osmia) cornifrons (Radoszkowski, 1887) *
Osmia (Osmia) lignaria lignaria Say, 1837
Osmia (Osmia) taurus Smith, 1873 *
Genus Paranthidium — 1 species
Paranthidium (Proanthidium) jugatorium jugatorium (Say, 1824)
Genus Pseudoanthidium — 1 species
Pseudoanthidium (Pseudoanthidium) nanum (Mocsáry, 1881) *
Genus Stelis — 5 species
Stelis (Dolichostelis) louisae Cockerell, 1911
Stelis (Stelis) coarctatus Crawford, 1916
Stelis (Stelis) foederalis Smith, 1854
Stelis (Stelis) labiata (Provancher, 1888)
Stelis (Stelis) lateralis Cresson, 1864
Additional information about species in this family is available at:
References
- Kilpatrick SK, Gibbs J, Mikulas MM, Spichiger S-E, Ostiguy N, Biddinger DJ, López-Uribe MM (2020) An updated checklist of the bees (Hymenoptera, Apoidea, Anthophila) of Pennsylvania, United States of America. Journal of Hymenoptera Research 77: 1–86. https://doi.org/10.3897/jhr.77.49622
- Ascher JS, Pickering J (2020) Discover Life bee species guide and world checklist (Hymenoptera: Apoidea: Anthophila). http://www.discoverlife.org/mp/20q?guide=Apoidea_species
Photo Credit
USGS Bee Inventory and Monitoring Lab
How to Cite this Webpage
Kilpatrick SK, López-Uribe MM (2020) Megachilidae. http://lopezuribelab.com/megachilidae/
Updated 29 June 2020