Hoplitis

Taxonomy

Family: Megachilidae
Subfamily: Megachilinae
Tribe: Osmiini
Genus: Hoplitis Klug, 1807
Subgenera: Alcidamea, Anthocopa, Chlidoplitis, Eurypariella, Formicapis, Hoplitis, Jaxartinula, Kumobia, Megahoplitis, Micreriades, Pentadentosmia, Platosmia, Proteriades, Robertsonella, Stenosmia, Tkalcua
Common name: mason bees

Overview

Hoplitis range in body length from 3–18 mm and range in body form from slender and elongate to robust (Michener 2007Michener 2007:
Michener, C.D. 2007. The Bees of the World (2nd ed.). Johns Hopkins University Press, Baltimore and London, 953 pp.). Hoplitis are generally nonmetallic, apart from a few common North American species which can be vibrantly metallic green (Michener 2007Michener 2007:
Michener, C.D. 2007. The Bees of the World (2nd ed.). Johns Hopkins University Press, Baltimore and London, 953 pp.).

Diversity

Hoplitis contains approximately 360 described species in 16 subgenera worldwide (Michener 2007Michener 2007:
Michener, C.D. 2007. The Bees of the World (2nd ed.). Johns Hopkins University Press, Baltimore and London, 953 pp.; Sedivy et al. 2013Sedivy et al. 2013:
Sedivy, C., S. Dorn, and A. Muller. 2013. Molecular phylogeny of the bee genus Hoplitis (Megachilidae: Osmiini) ndash; how does nesting biology affect biogeography? Zoological Journal 167: 28ndash;42.). Nearly 60 species in 11 subgenera are found within the United States (Ascher and Pickering 2016; Wilson and Carril 2016Wilson and Carril 2016:
Wilson, J.S. and O.M. Carril. 2016. The Bees in Your Backyard: A Guide to North Americarsquo;s Bees. Princeton University Press, Princeton and Oxford, 288 pp.). In general, bees are more diverse in desert habitats; however, Hoplitis are more diverse in boreal and cool mountain habitats (Wilson and Carril 2016Wilson and Carril 2016:
Wilson, J.S. and O.M. Carril. 2016. The Bees in Your Backyard: A Guide to North Americarsquo;s Bees. Princeton University Press, Princeton and Oxford, 288 pp.).  

Diagnostic characteristics

(modified from Michener 2007Michener 2007:
Michener, C.D. 2007. The Bees of the World (2nd ed.). Johns Hopkins University Press, Baltimore and London, 953 pp.)

• Arolia present.
• Juxtantennal carinacarina:
  a clearly defined ridge or keel, not necessarily high or acute; usually appears on bees as simply a raised line
  absent.
• Parapsidal line parapsidal line:
  the line that runs submedially along the scutum and corresponds to the median border of the site of origin for flight muscles
  linear and elongate.
• Stigma stigma:
  a pigmented/ thickened spot on the costal margin of the forewing, usually at the end of the radius(Greek, stigma= mark)
  twice as long as broad or more.
• T1 convexconvex:
  curved outward
  or flat except for a longitudinal median depression.
• Wing with two submarginal cellssubmarginal cells:
  one or more cells of the wing lying immediately behind the marginal cells
  .
• Female tarsal claws simple.
• Male S6S6:
  the plates on the underside of the abdomen, often abbreviated when referring to a specific segment to S1, S2, S3, S4, S5, S6, S7, or S8
  with a pair of thin, translucent, and hairless basalbasal:
  originating at the foundation of a structure
  flaps, except in the subgenus Pentadentosmia.
• Male T6T6:
  the segments on the top side of the abdomen, often abbreviated when referring to a specific segment to T1, T2, T3, T4, T5, T6, or T7
  with laterallateral:
  relating, pertaining, or attached to the side
  tooth, except in the subgenus Megahoplitis.

May be confused with

Hoplitis may be confused with Osmia due to similar body shapes and the presence of the laterallateral:
relating, pertaining, or attached to the side
tooth of male T6; however, Hoplitis can be differentiated by the characteristics listed above (Michener 2007Michener 2007:
Michener, C.D. 2007. The Bees of the World (2nd ed.). Johns Hopkins University Press, Baltimore and London, 953 pp.).

Known invasives

Hoplitis anthocopoides was accidentally introduced into Albany County, New York in the 1960s (Eickwort 1970Eickwort 1970:
Eickwort, G.C. 1970. Hoplitis anthocopoides, a European mason bee established in New York state (Hymenoptera: Megachilidae).; Wilson and Carril 2016Wilson and Carril 2016:
Wilson, J.S. and O.M. Carril. 2016. The Bees in Your Backyard: A Guide to North Americarsquo;s Bees. Princeton University Press, Princeton and Oxford, 288 pp.) via host plant introduction. Hoplitis anthocopoides is native to Europe and can be found as far north as Scandinavia and as far south as Greece (Eickwort 1970Eickwort 1970:
Eickwort, G.C. 1970. Hoplitis anthocopoides, a European mason bee established in New York state (Hymenoptera: Megachilidae).). Hoplitis anthocopoides is dependent on Echium vulgare and Anchusa officinalis, which are introduced weeds commonly found in disturbed sites such as roadsides (Eickwort 1970Eickwort 1970:
Eickwort, G.C. 1970. Hoplitis anthocopoides, a European mason bee established in New York state (Hymenoptera: Megachilidae).). They build their nests on the surface of rocks using mortar and pebbles, which are rarely used by native bees (Eickwort 1970Eickwort 1970:
Eickwort, G.C. 1970. Hoplitis anthocopoides, a European mason bee established in New York state (Hymenoptera: Megachilidae).). Due to the abundance of their host plants and accessible nesting sites, H. anthocopoides will likely extend its range throughout eastern North America (Eickwort 1970Eickwort 1970:
Eickwort, G.C. 1970. Hoplitis anthocopoides, a European mason bee established in New York state (Hymenoptera: Megachilidae).).

Host associations

Plant host preferences are species dependent. Several Hoplitis species are generalists, and will visit any blooming plant. Other species select plants within multiple families such as Fabaceae and Boraginaceae, or specialize on a single plant family such Hydrophyllaceae, Fabaceae, or Boraginaceae. A few species are dependent on a single plant genus, such as Phacelia, Acmispon, Hosakia, Larrea, or Penstemon (Wilson and Carril 2016Wilson and Carril 2016:
Wilson, J.S. and O.M. Carril. 2016. The Bees in Your Backyard: A Guide to North Americarsquo;s Bees. Princeton University Press, Princeton and Oxford, 288 pp.).

Species within the subgenera Penteriades and Proteriades specialize strictly on Cryptantha. Penteriades and Proteriades have hooked bristles on their proboscisproboscis:
an elongated sucking mouthpart that is typically tubular and flexible
that allows them to harvest pollen located in the narrow flower tubes (Müller 2006; Michener 2007Michener 2007:
Michener, C.D. 2007. The Bees of the World (2nd ed.). Johns Hopkins University Press, Baltimore and London, 953 pp.). The bee then moves the pollen from the bristles on the proboscisproboscis:
an elongated sucking mouthpart that is typically tubular and flexible
to the abdominal scopascopa:
modified hairs for carrying pollen; often branched and dense hairs on the hind-leg, or on the ventral surface of the abdomen in Megachilidae
for transport to the nest (Müller 2006).

Nesting behavior

Hoplitis are solitary bees. Nesting habits are species specific and diverse, ranging from nesting in excavated burrows in soil, cracks in rocks, or pithy plant stems to pre-existing abandoned beetle, wasp, and bee burrows, empty galls, and empty snail shells (Wilson and Carril 2016Wilson and Carril 2016:
Wilson, J.S. and O.M. Carril. 2016. The Bees in Your Backyard: A Guide to North Americarsquo;s Bees. Princeton University Press, Princeton and Oxford, 288 pp.). Hoplitis will use specific materials such as leaf pulp, pebbles, masticated leaves, bits of wood, resin, clay, sand, and petals to create partitions between cells and nest plugs (Michener 2007Michener 2007:
Michener, C.D. 2007. The Bees of the World (2nd ed.). Johns Hopkins University Press, Baltimore and London, 953 pp.). Materials are used alone and in combination with one another, depending on the species or subgenus (Michener 2007Michener 2007:
Michener, C.D. 2007. The Bees of the World (2nd ed.). Johns Hopkins University Press, Baltimore and London, 953 pp.). For example, species within the subgenera Alcidamea and Formicapis build nests in pithy stems, and use leaf pulp, pith particles, and/or pebbles to create the walls between cells (Michener 2007Michener 2007:
Michener, C.D. 2007. The Bees of the World (2nd ed.). Johns Hopkins University Press, Baltimore and London, 953 pp.). Further, species within the subgenus Anthocopa create short burrows in the soil with each burrow ending in a single cell. They line cells with brightly colored petals and pack the upper portion of the burrow with mud (Michener 2007Michener 2007:
Michener, C.D. 2007. The Bees of the World (2nd ed.). Johns Hopkins University Press, Baltimore and London, 953 pp.).

Distribution

Hoplitis is one of the largest and most wide-ranging genera of Osmiini (Michener 2007Michener 2007:
Michener, C.D. 2007. The Bees of the World (2nd ed.). Johns Hopkins University Press, Baltimore and London, 953 pp.; Wilson and Carril 2016Wilson and Carril 2016:
Wilson, J.S. and O.M. Carril. 2016. The Bees in Your Backyard: A Guide to North Americarsquo;s Bees. Princeton University Press, Princeton and Oxford, 288 pp.). They are found on every continent except Australia, South America, and Antarctica (Sedivy et al. 2013Sedivy et al. 2013:
Sedivy, C., S. Dorn, and A. Muller. 2013. Molecular phylogeny of the bee genus Hoplitis (Megachilidae: Osmiini) ndash; how does nesting biology affect biogeography? Zoological Journal 167: 28ndash;42.). Within the U.S., Hoplitis are more diverse along the west coast than the east coast. However, some species (e.g., H. anthocopoides) are found exclusively in the east, whereas others (e.g. H. robusta) occur throughout North America (Wilson and Carril 2016Wilson and Carril 2016:
Wilson, J.S. and O.M. Carril. 2016. The Bees in Your Backyard: A Guide to North Americarsquo;s Bees. Princeton University Press, Princeton and Oxford, 288 pp.).

​Distribution map generated by Discover Life -- click on map for details, credits, and terms of use.

References

Eickwort, G.C. 1970. Hoplitis anthocopoides, a European mason bee established in New York state (Hymenoptera: Megachilidae).

Michener, C.D. 2007. The Bees of the World. 2nd ed. Johns Hopkins University Press, Baltimore and London, 953 pp. Psyche 77: 190-201.

Müller, A. 2006. Unusual host plant of Hoplitis pici, a bee with hooked bristles on its mouthparts (Hymenoptera: Megachilidae: Osmiini). European Journal of Entomology 103: 497-500.

Sedivy, C., S. Dorn, and A. Muller. 2013. Molecular phylogeny of the bee genus Hoplitis (Megachilidae: Osmiini) – how does nesting biology affect biogeography? Zoological Journal 167: 28-42.

Wilson, J.S. and O.M. Carril. 2016. The Bees in Your Backyard: A Guide to North America’s Bees. Princeton University Press.