Megachile (Addendella)

Taxonomy

Family: Megachilidae
Subfamily: Megachilinae
Tribe: Megachilini
Genus: Megachile Latreille, 1802
Subgenus: Addendella Mitchell, 1980
Common name: none

Overview

Megachile (Addendella) are robust bees with black integumentintegument:
a tough, protective outer layer
. They have primarily white hair on their body with some black hair on the head, scutumscutum:
the large segment on top of the thorax located between the wings and behind the head
, scutellumscutellum:
shield shaped plate behind scutum
, the discs of the tergaterga:
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 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
(Mitchell 1935bMitchell 1935b:
Mitchell, T.B. 1935. A revision of the genus Megachile in the Nearctic region. Part III. Taxonomy of subgenera Anthemois and Delomegachile (Hymenoptera: Megachilidae). Transactions of the American Entomological Society 61(3): 155-205.). Their body length ranges from 10–17 mm (Mitchell 1935bMitchell 1935b:
Mitchell, T.B. 1935. A revision of the genus Megachile in the Nearctic region. Part III. Taxonomy of subgenera Anthemois and Delomegachile (Hymenoptera: Megachilidae). Transactions of the American Entomological Society 61(3): 155-205., Michener 2007Michener 2007:
Michener, C.D. 2007. The Bees of the World (2nd ed.). Johns Hopkins University Press, Baltimore and London, 953 pp.). Megachile (Addendella) are univoltine, and adults have been observed flying from May to early July (Mitchell 1935bMitchell 1935b:
Mitchell, T.B. 1935. A revision of the genus Megachile in the Nearctic region. Part III. Taxonomy of subgenera Anthemois and Delomegachile (Hymenoptera: Megachilidae). Transactions of the American Entomological Society 61(3): 155-205.). This subgenus was previously synonymized with Megachile (Xanthosarus), but was revived by Gonzalez et al. 2019Gonzalez et al. 2019:
Gonzalez, V.H., G.T. Gustafson, and M.S. Engel. 2019. Morphological phylogeny of Megachilini and the evolution of leaf-cutter behavior in bees (Hymenoptera: Megachilidae). Journal of Melittology (85): 1-123..

Diagnostic characteristics

(modified from Mitchell 1935bMitchell 1935b:
Mitchell, T.B. 1935. A revision of the genus Megachile in the Nearctic region. Part III. Taxonomy of subgenera Anthemois and Delomegachile (Hymenoptera: Megachilidae). Transactions of the American Entomological Society 61(3): 155-205.; Sheffield et al. 2011bSheffield et al. 2011b:
Sheffield, C.S., C. Ratti, L. Packer, and T. Griswold. 2011. Leafcutter and mason bees of the genus Megachile Latreille (Hymenoptera: Megachilidae) in Canada and Alaska. Canadian Journal of Arthropod Identification 18: 1-107.)

• Female clypeusclypeus:
  a section of the face below the antennae, demarcated by the epistomal sutures
  distinctly and closely punctatepunctate:
  studded with tiny holes
  with a crenulatecrenulate:
  having a finely scalloped or notched outline or edge
  or denticulatedenticulate:
  a small tooth-like projection
  apicalapical:
  near or at the apex or end of any structure
  margin.
• Female mandiblemandible:
  bee teeth, so to speak, usually crossed and folded in front of the mouth
  four-toothed with an acute upper tooth. The cutting edge in the first interspace is incomplete and very small; the cutting edge in the second interspace is incomplete and large.
• Female S2–S5 with white scopal hairs.
• Female T2–T5 with carinacarina:
  a clearly defined ridge or keel, not necessarily high or acute; usually appears on bees as simply a raised line
  of basalbasal:
  originating at the foundation of a structure
  grooves strongly elevated.
• Female T2–T5 with black pubescencepubescence:
  short, fine hair
  on the discs, contrasting with the white apicalapical:
  near or at the apex or end of any structure
  hair bandsbands:
  usually referring to bands of hair or bands of color that traverse across an abdominal segment
  .
• 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
  strongly concave when viewed in profile.
• Male front coxacoxa:
  the basal segment of the leg
  with a spine that has a dense patch of red bristles at the base.
• Male front tarsitarsi:
  the group of segments at the end of the leg following the tibia
  simple, not modified or expanded.
• Male mandiblemandible:
  bee teeth, so to speak, usually crossed and folded in front of the mouth
  four-toothed (sometimes weakly) with a basalbasal:
  originating at the foundation of a structure
  projection on the lower 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
  with wide median emarginationemargination:
  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
  .
• 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
  apicalapical:
  near or at the apex or end of any structure
  margin with laterallateral:
  relating, pertaining, or attached to the side
  teeth but no sublateral teeth.

May be confused with

Megachile (Addendella) females can be confused with Megachile (Litomegachile) because of their similar four-toothed mandibles and concave 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
when viewed in profile. M. (Addendella) can be distinguished by their larger size and denticulatedenticulate:
a small tooth-like projection
clypeal margin (Mitchell 1935bMitchell 1935b:
Mitchell, T.B. 1935. A revision of the genus Megachile in the Nearctic region. Part III. Taxonomy of subgenera Anthemois and Delomegachile (Hymenoptera: Megachilidae). Transactions of the American Entomological Society 61(3): 155-205.; Michener 2007Michener 2007:
Michener, C.D. 2007. The Bees of the World (2nd ed.). Johns Hopkins University Press, Baltimore and London, 953 pp.). Male M. (Addendella) can look similar to Megachile (Argyropile) parallela in the wide emarginationemargination:
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
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
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
and the four-toothed mandibles. M. (Addendella) differ in their dense patch of red bristles at the base of the front coxacoxa:
the basal segment of the leg
and the absence of sublateral spines on the apicalapical:
near or at the apex or end of any structure
margin 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
(Mitchell 1935bMitchell 1935b:
Mitchell, T.B. 1935. A revision of the genus Megachile in the Nearctic region. Part III. Taxonomy of subgenera Anthemois and Delomegachile (Hymenoptera: Megachilidae). Transactions of the American Entomological Society 61(3): 155-205.).

Host associations

Megachile (Addendella) have been observed visiting the flowers of multiple plant families including Cactaceae, Ericaceae, Fabaceae, Hypericaceae, Onagraceae, and Plantaginaceae (Mitchell 1935bMitchell 1935b:
Mitchell, T.B. 1935. A revision of the genus Megachile in the Nearctic region. Part III. Taxonomy of subgenera Anthemois and Delomegachile (Hymenoptera: Megachilidae). Transactions of the American Entomological Society 61(3): 155-205.). They have also been shown to be effective pollinators of commercial cranberry (Cane et al. 1996Cane et al. 1996:
Cane, J.H., D. Schiffhauer, and L.J. Kervin. 1996. Pollination, foraging, and nesting ecology of the leaf-cutting bee Megachile (Delomegachile) addenda (Hymenoptera: Megachilidae) on cranberry beds. Annals of the Entomological Society of America 89(3): 361-367.). Females have been found cutting maple leaves (Acer rubrum) to line their nest cells, and males have been observed patrolling maple trees (Cane et al. 1996Cane et al. 1996:
Cane, J.H., D. Schiffhauer, and L.J. Kervin. 1996. Pollination, foraging, and nesting ecology of the leaf-cutting bee Megachile (Delomegachile) addenda (Hymenoptera: Megachilidae) on cranberry beds. Annals of the Entomological Society of America 89(3): 361-367.).

Nesting behavior

Megachile (Addendella) nest in the ground where they excavate their own nest cavity in the soil (Cane et al. 1996Cane et al. 1996:
Cane, J.H., D. Schiffhauer, and L.J. Kervin. 1996. Pollination, foraging, and nesting ecology of the leaf-cutting bee Megachile (Delomegachile) addenda (Hymenoptera: Megachilidae) on cranberry beds. Annals of the Entomological Society of America 89(3): 361-367.). The nests are usually shallow (4–17 cm) with a short main tunnel ending in horizontally arranged cells. Nest cells are lined with cut leaves and usually arranged singly or in groups of two, although they have sometimes been found arranged linearly, with 4–9 cells per nest (Cane et al. 1996Cane et al. 1996:
Cane, J.H., D. Schiffhauer, and L.J. Kervin. 1996. Pollination, foraging, and nesting ecology of the leaf-cutting bee Megachile (Delomegachile) addenda (Hymenoptera: Megachilidae) on cranberry beds. Annals of the Entomological Society of America 89(3): 361-367.).

Diversity

Megachile (Addendella) includes a single species, Megachile addenda (Gonzalez et al. 2019Gonzalez et al. 2019:
Gonzalez, V.H., G.T. Gustafson, and M.S. Engel. 2019. Morphological phylogeny of Megachilini and the evolution of leaf-cutter behavior in bees (Hymenoptera: Megachilidae). Journal of Melittology (85): 1-123.).

Known invasives

There are no known invasives.

Distribution

Megachile (Addendella) are known primarily from the eastern U.S. from southeastern Canada south to Florida (Mitchell 1935). They have been reported in the southern part ofthe U.S. as far west as California,but are mostly found east of Kansas (Mitchell 1935).

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References

Cane, J.H., D. Schiffhauer, and L.J. Kervin. 1996. Pollination, foraging, and nesting ecology of the leaf-cutting bee Megachile (Delomegachile) addenda (Hymenoptera: Megachilidae) on cranberry beds. Annals of the Entomological Society of America 89(3): 361-367.

Gonzalez, V.H., G.T. Gustafson, and M.S. Engel. 2019. Morphological phylogeny of Megachilini and the evolution of leaf-cutter behavior in bees (Hymenoptera: Megachilidae). Journal of Melittology 85: 1-123.

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

Mitchell, T.B. 1935. 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 III. Taxonomy of subgenera Anthemois and Delomegachile (Hymenoptera: Megachilidae). Transactions of the American Entomological Society 61(3): 155-205.

Sheffield, C.S., C. Ratti, L. Packer, and T. Griswold. 2011. Leafcutter and mason bees of the genus Megachile Latreille (Hymenoptera: Megachilidae) in Canada and Alaska. Canadian Journal of Arthropod Identification 18: 1-107.