Gronoceras

Taxonomy

Family: Megachilidae
Subfamily: Megachilinae
Tribe: Megachilini
Genus: Gronoceras Cockerell, 1907
Subgenera: none
Common name: none

Overview

Gronoceras are large, elongate bees ranging in body length from 17–29 mm (Michener 2007Michener 2007:
Michener, C.D. 2007. The Bees of the World (2nd ed.). Johns Hopkins University Press, Baltimore and London, 953 pp.). They often have black integumentintegument:
a tough, protective outer layer
with grey and black pubescencepubescence:
short, fine hair
in addition to large areas of red or reddish-yellow pubescencepubescence:
short, fine hair
on their thorax and head (Michener 2007Michener 2007:
Michener, C.D. 2007. The Bees of the World (2nd ed.). Johns Hopkins University Press, Baltimore and London, 953 pp.). Gronoceras was previously a subgenus of Megachile (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.).

Diversity

Gronoceras contains 10 species (Michener 2007Michener 2007:
Michener, C.D. 2007. The Bees of the World (2nd ed.). Johns Hopkins University Press, Baltimore and London, 953 pp.); none are known to occur in the U.S. or 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 absent.
• Front and middle tibiatibia:
  the segment of the leg, between the femur and the tarsus
  with three apicalapical:
  near or at the apex or end of any structure
  spines.
• Preoccipital carinacarina:
  a clearly defined ridge or keel, not necessarily high or acute; usually appears on bees as simply a raised line
  absent (Gonzalez 2008Gonzalez 2008:
  Gonzalez, V.H. 2008. Phylogeny and classification of the bee tribe Megachilini (Hymenoptera: Apoidea: Megachilidae), with emphasis on the genus Megachile. Thesis: Department of Ecology and Evolutionary Biology and the College of Liberal Arts and Science of the University of Kansas: 1-274.).
• Pronotal lobes without carinacarina:
  a clearly defined ridge or keel, not necessarily high or acute; usually appears on bees as simply a raised line
  (Gonzalez 2008Gonzalez 2008:
  Gonzalez, V.H. 2008. Phylogeny and classification of the bee tribe Megachilini (Hymenoptera: Apoidea: Megachilidae), with emphasis on the genus Megachile. Thesis: Department of Ecology and Evolutionary Biology and the College of Liberal Arts and Science of the University of Kansas: 1-274.).
• Stigma stigma:
  a pigmented/ thickened spot on the costal margin of the forewing, usually at the end of the radius(Greek, stigma= mark)
  over twice as long as broad.
• Female mandiblemandible:
  bee teeth, so to speak, usually crossed and folded in front of the mouth
  four-toothed without cutting edges, with the two lower teeth being close together .
• Male with carinacarina:
  a clearly defined ridge or keel, not necessarily high or acute; usually appears on bees as simply a raised line
  made up of long spines or lobes, partly hidden by dense long hairs (Gonzalez 2008Gonzalez 2008:
  Gonzalez, V.H. 2008. Phylogeny and classification of the bee tribe Megachilini (Hymenoptera: Apoidea: Megachilidae), with emphasis on the genus Megachile. Thesis: Department of Ecology and Evolutionary Biology and the College of Liberal Arts and Science of the University of Kansas: 1-274.).

May be confused with

Gronoceras may be confused with species in the subgenus Megachile (Stenomegachile) due to similar dense hairs on the 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
. Gronoceras can be differentiated by the presence of three apicalapical:
near or at the apex or end of any structure
spines on the front and middle tibiatibia:
the segment of the leg, between the femur and the tarsus
(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

There was a single record of Gronoceras in Jamaica that indicates it may have been introduced to the area, but there is no evidence that the genus established there (Michener 2007Michener 2007:
Michener, C.D. 2007. The Bees of the World (2nd ed.). Johns Hopkins University Press, Baltimore and London, 953 pp.).

Host associations

Gronoceras have been observed pollinating Ansellia africana, Cajanus cajan, and Vanilla imperialis (FAOUNR 2008FAOUNR 2008:
Food and Agriculture Organization of the United Nations, Rome (FAOUNR). 2008. Tools for conservation and use of pollination services. Pollination Services for Sustainable Agriculture: 1ndash;143.; Martin 2009Martin 2009:
Martin, D.J. 2009. Pollination and facultative ant-association in the African leopard orchid Ansellia africana. Journal of East African Natural History 98: 67ndash;77.).

Nesting behavior

Similar to many subgenera of Megachile, Gronoceras build nests using resin (Litman 2012Litman 2012:
Litman, J.R. 2012. Phylogenetic systematics and the evolution of nesting behavior, host-plant preference, and cleptoparasitism in the bee family Megachilidae (Hymenoptera, Apoidea). Cornell University 2012: 1ndash;213.). Gronoceras has been observed nesting in earthen walls and wooden posts (FAOUNR 2008FAOUNR 2008:
Food and Agriculture Organization of the United Nations, Rome (FAOUNR). 2008. Tools for conservation and use of pollination services. Pollination Services for Sustainable Agriculture: 1ndash;143.).

Distribution

Gronoceras occurs throughout Africa, from Senegal to Eritrea, south to Namibia, and Natal in South Africa (Michener 2007Michener 2007:
Michener, C.D. 2007. The Bees of the World (2nd ed.). Johns Hopkins University Press, Baltimore and London, 953 pp.).

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

References

Food and Agriculture Organization of the United Nations, Rome (FAOUNR). 2008. Tools for conservation and use of pollination services. Pollination Services for Sustainable Agriculture: 1-143.

Gonzalez, V.H. 2008. Phylogeny and classification of the bee tribe Megachilini (Hymenoptera: Apoidea, Megachilidae), with emphasis on the genus Megachile. Doctoral dissertation, University of Kansas.

Litman, J.R. 2012. Phylogenetic systematics and the evolution of nesting behavior, host-plant preference, and cleptoparasitism in the bee family Megachilidae (Hymenoptera, Apoidea). Cornell University 2012: 1-213.

Martin, D.J. 2009. Pollination and facultative ant-association in the African leopard orchid Ansellia africana. Journal of East African Natural History 98: 67-77.

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

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.