Megachile (Phaenosarus)

Taxonomy

Family: Megachilidae
Subfamily: Megachilinae
Tribe: Megachilini
Genus: Megachile Latreille, 1802
Subgenus: Phaenosarus Mitchell, 1934
Common name: none

Overview

Megachile (Phaenosarus) bees have almost entirely black integumentintegument:
a tough, protective outer layer
with reddish tegulategula:
the usually oval, small shield-like structure carried at the extreme base of the wing where it attaches to the body
and white to ochre hairs (Mitchell 1936Mitchell 1936:
Mitchell, T.B. 1936. A revision of the genus Megachile in the Nearctic region. Part IV. Taxonomy of subgenera Xanthosarus, Phaenosarus, Megachiloides and Derotropis (Hymenoptera: Megachilidae). Transactions of the American Entomological Society 62(2): 117-166.). Females range in body length from 14–18 mm, and males range in body length from 13–15 mm (Mitchell 1936Mitchell 1936:
Mitchell, T.B. 1936. A revision of the genus Megachile in the Nearctic region. Part IV. Taxonomy of subgenera Xanthosarus, Phaenosarus, Megachiloides and Derotropis (Hymenoptera: Megachilidae). Transactions of the American Entomological Society 62(2): 117-166.). This subgenus was previously synonymized with Megachile (Xanthosarus), but it was reestablished as a subgenus by Gonzalez et al. (2019).

Diagnostic characteristics

(modified from Mitchell 1936Mitchell 1936:
Mitchell, T.B. 1936. A revision of the genus Megachile in the Nearctic region. Part IV. Taxonomy of subgenera Xanthosarus, Phaenosarus, Megachiloides and Derotropis (Hymenoptera: Megachilidae). Transactions of the American Entomological Society 62(2): 117-166.)

• Female mandiblemandible:
  bee teeth, so to speak, usually crossed and folded in front of the mouth
  is five-toothed with an incomplete cutting edge in the second interspace and a complete cutting edge in the third interspace.
• Female 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
  sparsely covered with scopal hairs, with the apicalapical:
  near or at the apex or end of any structure
  margin of the plate somewhat thickened apicallyapically:
  near or at the apex or end of any structure
  .
• Female 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 appressed pubescencepubescence:
  short, fine hair
  over the apicalapical:
  near or at the apex or end of any structure
  half.
• Male mandiblemandible:
  bee teeth, so to speak, usually crossed and folded in front of the mouth
  is three-toothed with a basalbasal:
  originating at the foundation of a structure
  projection on the lower margin.
• Male front tarsitarsi:
  the group of segments at the end of the leg following the tibia
  are broadly expanded.
• Male S4S4:
  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 small, distinct median tubercletubercle:
  a small knob-like or rounded protuberance
  on the apicalapical:
  near or at the apex or end of any structure
  margin.
• 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
  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
  triangular with a truncatetruncate:
  ending abruptly, or squared off
  apexapex:
  end of any structure
  , not at all emarginateemarginate:
  a notched or cut out place in an edge or margin, can be dramatic or simply a subtle inward departure from the general curve or line of the margin or structure being described
  although often denticulatedenticulate:
  a small tooth-like projection
  or crenulatecrenulate:
  having a finely scalloped or notched outline or edge
  .
• Male T7T7:
  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
  somewhat pointed medially.

May be confused with

Megachile (Phaenosarus) is often very similar to Megachile (Xanthosarus) in size, coloration, five-toothed mandibles (in females), and the expanded front tarsitarsi:
the group of segments at the end of the leg following the tibia
of the males (Mitchell 1936Mitchell 1936:
Mitchell, T.B. 1936. A revision of the genus Megachile in the Nearctic region. Part IV. Taxonomy of subgenera Xanthosarus, Phaenosarus, Megachiloides and Derotropis (Hymenoptera: Megachilidae). Transactions of the American Entomological Society 62(2): 117-166.; Michener 2007Michener 2007:
Michener, C.D. 2007. The Bees of the World (2nd ed.). Johns Hopkins University Press, Baltimore and London, 953 pp.). Megachile (Phaenosarus) females can be differentiated from Megachile (Xanthosarus) by the appressed pubescencepubescence:
short, fine hair
on the apicalapical:
near or at the apex or end of any structure
half of 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
and the length of 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
, which extends slightly beyond the apexapex:
end of any structure
of the 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
(Mitchell 1936Mitchell 1936:
Mitchell, T.B. 1936. A revision of the genus Megachile in the Nearctic region. Part IV. Taxonomy of subgenera Xanthosarus, Phaenosarus, Megachiloides and Derotropis (Hymenoptera: Megachilidae). Transactions of the American Entomological Society 62(2): 117-166.). Male Megachile (Phaenosarus) can be differentiated by the presence of a small median tubercletubercle:
a small knob-like or rounded protuberance
on the apicalapical:
near or at the apex or end of any structure
margin of S4S4:
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
(Mitchell 1936Mitchell 1936:
Mitchell, T.B. 1936. A revision of the genus Megachile in the Nearctic region. Part IV. Taxonomy of subgenera Xanthosarus, Phaenosarus, Megachiloides and Derotropis (Hymenoptera: Megachilidae). Transactions of the American Entomological Society 62(2): 117-166.).

Host associations

Megachile (Phaenosarus) fortis has been observed visiting flowers of Asteraceae, and they are believed to be valuable pollinators of commercial sunflowers (Helianthus annuus) (Neff and Simpson 1991Neff and Simpson 1991:
Neff, J.L. and B.B. Simpson. 1991. Nest biology and mating behavior of Megachile fortis in Central Texas (Hymenoptera: Megachilidae). Journal of the Kansas Entomological Society 64: 324-336.; Sheffield et al. 2014Sheffield et al. 2014:
Sheffield, C.S., S.D. Frier, and S. Dumesh. 2014. The Bees (Hymenoptera: Apoidea, Apiformes) of the Prairies Ecozone, with Comparisons to other Grasslands of Canada. In Arthropods of Canadian Grasslands (Volume 4): Biodiversity and Systematics Part 2. Edited by D. J. Giberson and H. A. Caacute;rcamo. Biological Survey of Canada. pp. 427-467.).

Nesting behavior

Megachile (Phaenosarus) constructs nests cells primarily from leaf pieces (Neff and Simpson 1991Neff and Simpson 1991:
Neff, J.L. and B.B. Simpson. 1991. Nest biology and mating behavior of Megachile fortis in Central Texas (Hymenoptera: Megachilidae). Journal of the Kansas Entomological Society 64: 324-336.). Megachile (Phaenosarus) fortis excavate nests in hard-packed, level soil (Hicks 1926Hicks 1926:
Hicks, C.H. 1926. Nesting habits and parasites of certain bees of Boulder County, Colorado. University of Colorado Bulletin 15: 217ndash;252.; Eickwort et al. 1981Eickwort et al. 1981:
Eickwort, G.C., R.W. Matthews, and J. Carpenter. 1981. Observations on the nesting behavior of Megachile rubi and M. texana with a discussion of the significance of soil nesting in the evolution of megachilid bees (Hymenoptera: Megachilidae). Journal of the Kansas Entomological Society. 54: 557-570., Neff and Simpson 1991Neff and Simpson 1991:
Neff, J.L. and B.B. Simpson. 1991. Nest biology and mating behavior of Megachile fortis in Central Texas (Hymenoptera: Megachilidae). Journal of the Kansas Entomological Society 64: 324-336.). Their nests contain between 1 and 9 cells (Neff and Simpson 1991Neff and Simpson 1991:
Neff, J.L. and B.B. Simpson. 1991. Nest biology and mating behavior of Megachile fortis in Central Texas (Hymenoptera: Megachilidae). Journal of the Kansas Entomological Society 64: 324-336.). Megachile fortis have been observed displaying territorial behavior, whereby they hover briefly and then pounce on the other male bees (regardless of species) (Neff and Simpson 1991Neff and Simpson 1991:
Neff, J.L. and B.B. Simpson. 1991. Nest biology and mating behavior of Megachile fortis in Central Texas (Hymenoptera: Megachilidae). Journal of the Kansas Entomological Society 64: 324-336.).

Diversity

Megachile (Phaenosarus) is a small subgenus of two species: M. agustini and M. fortis (Mitchell 1936Mitchell 1936:
Mitchell, T.B. 1936. A revision of the genus Megachile in the Nearctic region. Part IV. Taxonomy of subgenera Xanthosarus, Phaenosarus, Megachiloides and Derotropis (Hymenoptera: Megachilidae). Transactions of the American Entomological Society 62(2): 117-166.; Trunz et al. 2016Trunz et al. 2016:
Trunz, V., L. Packer, J. Vieu, N. Arrigo, and C.J. Praz. 2016. Comprehensive phylogeny, biogeography and new classification of the diverse bee tribe Megachilini: Can we use DNA barcodes in phylogenies of large genera? Molecular Phylogenetics and Evolution 103: 245ndash;259.).

Known invasives

There are no known invasives.

Distribution

Megachile (Phaenosarus) is a North American subgenus found from Mexico to Canada (Estrada 1992Estrada 1992:
Estrada, C.M. 1992. Abejas silvestres (Hymenoptera: Apoidea) de la Sierra del Tigre, Jalisco. Bs. Thesis. Facultad de Ciencias Biologicas, Universidad de Guadalajara. Guadalajara, Jalisco, Mexico. 93 pp.; Vergara and Ayala 2002Vergara and Ayala 2002:
Vergara, C. H. and R. Ayala. 2002. Diversity, phenology and biogeography of the bees (Hymenoptera: Apoidea) of Zapotitlan de las Salinas, Puebla, Mexico. Journal of the Kansas Entomological Society: 16-30.; Sheffield et al. 2014Sheffield et al. 2014:
Sheffield, C.S., S.D. Frier, and S. Dumesh. 2014. The Bees (Hymenoptera: Apoidea, Apiformes) of the Prairies Ecozone, with Comparisons to other Grasslands of Canada. In Arthropods of Canadian Grasslands (Volume 4): Biodiversity and Systematics Part 2. Edited by D. J. Giberson and H. A. Caacute;rcamo. Biological Survey of Canada. pp. 427-467.). This group is widely distributed in the U.S. throughout Utah, Colorado, Arizona, New Mexico, South Dakota, Kansas, Louisiana, Nebraska, and Iowa (Mitchell 1936Mitchell 1936:
Mitchell, T.B. 1936. A revision of the genus Megachile in the Nearctic region. Part IV. Taxonomy of subgenera Xanthosarus, Phaenosarus, Megachiloides and Derotropis (Hymenoptera: Megachilidae). Transactions of the American Entomological Society 62(2): 117-166.).

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References

Eickwort, G.C., R.W. Matthews, and J. Carpenter. 1981. Observations on the nesting behavior of Megachile rubi and M. texana with a discussion of the significance of soil nesting in the evolution of Megachilid bees (Hymenoptera: Megachilidae). Journal of the Kansas Entomological Society 54: 557-570.

Estrada, C.M. 1992. Abejas silvestres (Hymenoptera: Apoidea) de la Sierra del Tigre, Jalisco. Bs. Thesis. Facultad de Ciencias Biologicas, Universidad de Guadalajara. Guadalajara, Jalisco, Mexico. 93 pp.

Hicks, C.H. 1926. Nesting habits and parasites of certain bees of Boulder County, Colorado. University of Colorado Studies 26: 217-252.

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

Mitchell, T.B. 1936. A revision of the genus Megachile in the NearcticNearctic:
biogeographical region comprising North America as far south as northern Mexico, together with Greenland
region. Part IV. Taxonomy of the subgenera Xanthosarus, Phaenosarus, Megachiloides, and Derotropis. Transactions of the American Entomological Society 62: 117-166.

Neff, J.L. and B.B. Simpson. 1991. Nest biology and mating behavior of Megachile fortis in Central Texas (Hymenoptera: Megachilidae). Journal of the Kansas Entomological Society 64: 324-336.

Sheffield, C.S., S.D. Frier, and S. Dumesh. 2014. The Bees (Hymenoptera: Apoidea, Apiformes) of the Prairies Ecozone, with Comparisons to other Grasslands of Canada. In Arthropods of Canadian Grasslands (Volume 4): Biodiversity and Systematics Part 2. Edited by D. J. Giberson and H. A. Cárcamo. Biological Survey of Canada. pp. 427-467.

Trunz, V., L. Packer, J. Vieu, N. Arrigo, and C.J. Praz. 2016. Comprehensive phylogeny, biogeography and new classification of the diverse bee tribe Megachilini: Can we use DNA barcodes in phylogenies of large genera?. Molecular Phylogenetics and Evolution 103: 245-259.

Vergara, C. H. and R. Ayala. 2002. Diversity, phenology and biogeography of the bees (Hymenoptera: Apoidea) of Zapotitlan de las Salinas, Puebla, Mexico. Journal of the Kansas Entomological Society: 16-30.