Protosmia

Taxonomy

Family: Megachilidae
Subfamily: Megachilinae
Tribe: Osmiini
Genus: Protosmia Ducke, 1900
Subgenera: Chelostomopsis, Dolichosmia, Nanosmia, Protosmia
Common name: none

Overview

Protosmia are finely punctured, black bees with white hair on the thorax that range in body length from 3.5–9.5 mm. Body form can range from stocky and robust to slender. Protosmia are most often seen flying in the spring (Griswold 1985Griswold 1985:
Griswold, T. 1985. A generic and subgeneric revision of the Heriades genus-group. Logan: Ph.D. thesis, Utah State University. xiii + 165 pp.). The females of the only North American species, P. rubifloris, are easily recognizable by their distinct spatula-like process projecting out from the clypeusclypeus:
a section of the face below the antennae, demarcated by the epistomal sutures
(Michener 2007Michener 2007:
Michener, C.D. 2007. The Bees of the World (2nd ed.). Johns Hopkins University Press, Baltimore and London, 953 pp.).

Diversity

Protosmia contains 30 species in 4 subgenera worldwide; 1 species in 1 subgenus occurs in the U.S. and Canada (Michener 2007Michener 2007:
Michener, C.D. 2007. The Bees of the World (2nd ed.). Johns Hopkins University Press, Baltimore and London, 953 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. unless otherwise stated)

• Arolia present.
• Axilla axilla:
  the triangular or rounded point on the thorax where thoracic muscles meet the forewing of an insect
  rounded.
• Mesopleuron with ventralventral:
  of, on, or relating to the underside of an animal, or segment of an animal
  length shorter than its dorsaldorsal:
  in general, the upper surface
  length.
• Omaulus omaulus:
  angle between anterior and lateral surfaces of mesepisternum
  without carinacarina:
  a clearly defined ridge or keel, not necessarily high or acute; usually appears on bees as simply a raised line
  .
• Pronotal lobe pronotal lobe:
  a part of the pronotum located dorsally on the posterior margin of the pronotum and overlaps the anterior thoracic spiracle
  carinatecarinate:
  having keels or carinae
  or, if lacking carinacarina:
  a clearly defined ridge or keel, not necessarily high or acute; usually appears on bees as simply a raised line
  , with several minute carinacarina:
  a clearly defined ridge or keel, not necessarily high or acute; usually appears on bees as simply a raised line
  behind where pronotal carinacarina:
  a clearly defined ridge or keel, not necessarily high or acute; usually appears on bees as simply a raised line
  would be.
• Propodeum propodeum:
  the last segment of the thorax
  with pitted basalbasal:
  originating at the foundation of a structure
  horizontal zone present but not limited posteriorly by a distinct carinacarina:
  a clearly defined ridge or keel, not necessarily high or acute; usually appears on bees as simply a raised line
  .
• Preoccipital ridge preoccipital ridge:
  the carina that dorsolaterally surrounds the back of the head
  without carinacarina:
  a clearly defined ridge or keel, not necessarily high or acute; usually appears on bees as simply a raised line
  .
• Spatulate spatulate:
  having a broad, rounded end
  mid-apical projection on clypeusclypeus:
  a section of the face below the antennae, demarcated by the epistomal sutures
  (in North American species).
• Stigma stigma:
  a pigmented/ thickened spot on the costal margin of the forewing, usually at the end of the radius(Greek, stigma= mark)
  at least twice as long as broad. T1T1:
  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
  lacks carinacarina:
  a clearly defined ridge or keel, not necessarily high or acute; usually appears on bees as simply a raised line
  between dorsaldorsal:
  in general, the upper surface
  and anterioranterior:
  toward the head or on the head side of a segment being described
  surfaces (except in subgenus Afrosmia).
• T1 anterioranterior:
  toward the head or on the head side of a segment being described
  surface concave.
• Male S1S1:
  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 brush of hair under the margin (Griswold 1985Griswold 1985:
  Griswold, T. 1985. A generic and subgeneric revision of the Heriades genus-group. Logan: Ph.D. thesis, Utah State University. xiii + 165 pp.).
• Male S2S2:
  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
  and S3S3:
  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 posterior margins notched or stepped laterally (only in species from Eastern Hemisphere).
• 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
  lacks preapicalpreapical:
  referring to a section of a bee that is physically found just before the outermost (or apical) end of the section or segment
  carinacarina:
  a clearly defined ridge or keel, not necessarily high or acute; usually appears on bees as simply a raised line
  (unknown for P. burmanica).
• Female labrumlabrum:
  part of the head abutting the clypeus, folds down in front of the mouthparts
  with distinct preapicalpreapical:
  referring to a section of a bee that is physically found just before the outermost (or apical) end of the section or segment
  tuft of hair.

May be confused with

Protosmia may be confused with Othinosmia due to a similar thoracic structure. Both genera have a brush of hair under the S1S1:
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
margin (Michener 2007Michener 2007:
Michener, C.D. 2007. The Bees of the World (2nd ed.). Johns Hopkins University Press, Baltimore and London, 953 pp.). Othinosmia can be differentiated by the presence of a transverse preapicalpreapical:
referring to a section of a bee that is physically found just before the outermost (or apical) end of the section or segment
carinacarina:
a clearly defined ridge or keel, not necessarily high or acute; usually appears on bees as simply a raised line
on 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
of the male, and the distribution of Othinosmia is restricted to sub-Saharan Africa.

Known invasives

There are no known invasives.

Host associations

There are few published floral records associated with Protosmia species. Some Protosmia appear to prefer flowers in Lamiaceae and Fabaceae (Popov 1961Popov 1961:
Popov, V.V. 1961. On the evolution of the bee genera Protosmia Ducke and Chelostomopsis Cockerell. Zoologicheskii Zhurnal 40: 359ndash;371.). Protosmia rubifloris is considered a generalist but might specialize on Salvia based on pollen samples collected by Griswold (1986). 

Nesting behavior

Protosmia are solitary and known to nest in preexisting natural cavities. Protosmia rubifloris is presumed to nest in preexisting cavities in wood and has been found nesting in pinecones (Griswold 1986Griswold 1986:
Griswold, T. 1986. Notes on the nesting biology of Protosmia ( Chelostomopsis ) rubifloris (Cockerell) (Hymenoptera: Megachilidae). The Pan-Pacific Entomologist 62: 84ndash;87.). They do not line the cells, but rather form cell partitions of resin sometimes integrating an empty interstitial cell between brood cells. Nests are plugged after construction with resin with the occasional addition of small gravel bits (Griswold 1986Griswold 1986:
Griswold, T. 1986. Notes on the nesting biology of Protosmia ( Chelostomopsis ) rubifloris (Cockerell) (Hymenoptera: Megachilidae). The Pan-Pacific Entomologist 62: 84ndash;87.). Adults have been found overwintering within brood cells, a behavior that is not common in megachilids. Other Protosmia have been found to nest in hollow stems and members of the subgenus Protosmia utilize a variety of preexisting cavities, such as rock crevasses and abandoned mud wasp nests (summary by Griswold 1985Griswold 1985:
Griswold, T. 1985. A generic and subgeneric revision of the Heriades genus-group. Logan: Ph.D. thesis, Utah State University. xiii + 165 pp.). Multiple species have been noted to nest inside empty snail shells (Popov 1961Popov 1961:
Popov, V.V. 1961. On the evolution of the bee genera Protosmia Ducke and Chelostomopsis Cockerell. Zoologicheskii Zhurnal 40: 359ndash;371.).

Distribution

Protosmia has a disjunct distribution with most species occurring in the Mediterranean, North Africa, Europe, southwestern Asia, and northern India (Michener 2007Michener 2007:
Michener, C.D. 2007. The Bees of the World (2nd ed.). Johns Hopkins University Press, Baltimore and London, 953 pp.). However, P. (Chelostomopsis) rubifloris occurs in coastal, montane, and mid-elevational desert habitats of western North America, British Colombia, Canada, and Baja California, Mexico (Michener 2007Michener 2007:
Michener, C.D. 2007. The Bees of the World (2nd ed.). Johns Hopkins University Press, Baltimore and London, 953 pp.). Other species of the Chelostomopsis subgenus are known in the Mediterranean region from Morocco to Turkey and Lebanon (Michener 2007Michener 2007:
Michener, C.D. 2007. The Bees of the World (2nd ed.). Johns Hopkins University Press, Baltimore and London, 953 pp.). The only member of the Dolichosmia subgenus, P. burmanica, is a rare bee of Myanmar (Michener 2007Michener 2007:
Michener, C.D. 2007. The Bees of the World (2nd ed.). Johns Hopkins University Press, Baltimore and London, 953 pp.). The most widespread subgenus, Nanosmia, occurs throughout the Mediterranean region in Europe (Spain, Portugal, France, Greece), Africa (Morocco to Tunisia), the Middle East (Israel, Syria, Saudi Arabia, United Arab Emirates), Turkey, and Central Asia (Tajikistan, Pakistan, and Kashmir region of India). The Protosmia subgenus also inhabits the Mediterranean region, from Spain to Israel eastward to Turkey and Transcaucasia (Michener 2007Michener 2007:
Michener, C.D. 2007. The Bees of the World (2nd ed.). Johns Hopkins University Press, Baltimore and London, 953 pp.).

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References

Griswold, T. 1985. A generic and subgeneric revision of the Heriades genus-group. Logan: Ph.D. thesis, Utah State University. xiii + 165 pp.

Griswold, T. 1986. Notes on the nesting biology of Protosmia (Chelostomopsis) rubifloris (Cockerell) (Hymenoptera: Megachilidae). The Pan-Pacific Entomologist 62:84-87.

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

Popov, V.V. 1961. On the evolution of the bee genera Protosmia Ducke and Chelostomopsis Cockerell. Zoologicheskii Zhurnal 40: 359-371.