Metadioxys

Taxonomy

Family: Megachilidae
Subfamily: Megachilinae
Tribe: Dioxyini
Genus: Metadioxys Popov, 1947
Subgenera: none
Common name: none

Overview

Metadioxys have a similar external appearance to Dioxys, which are narrow-bodied, black bees with white apicalapical:
near or at the apex or end of any structure
bands on 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
. They range in body length from 10–11 mm (Michener 2007Michener 2007:
Michener, C.D. 2007. The Bees of the World (2nd ed.). Johns Hopkins University Press, Baltimore and London, 953 pp.).

Diversity

Metadioxys consists of three 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.

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.
• Axilla axilla:
  the triangular or rounded point on the thorax where thoracic muscles meet the forewing of an insect
  without tooth or spine.
• Front coxacoxa:
  the basal segment of the leg
  is strongly carinatecarinate:
  having keels or carinae
  .
• Labrum labrum:
  part of the head abutting the clypeus, folds down in front of the mouthparts
  with basalbasal:
  originating at the foundation of a structure
  transverse carinacarina:
  a clearly defined ridge or keel, not necessarily high or acute; usually appears on bees as simply a raised line
  .
• Metanotum metanotum:
  the posterior dorsal segment of the thorax, behind the scutellum
  with small median tubercletubercle:
  a small knob-like or rounded protuberance
  .
• 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
  .
• Propodeum propodeum:
  the last segment of the thorax
  with postspiricular foveafovea:
  a depressed region of cuticle; in bees this depressed area is usually only very slightly hollow and usually on the face.
  present and defined by carinacarina:
  a clearly defined ridge or keel, not necessarily high or acute; usually appears on bees as simply a raised line
  (Michener 1996Michener 1996:
  Michener, C.D. 1996. The first South African dioxyine bee and a generic review of the tribe Dioxyini (Hymenoptera, Megachilidae). Contributions on Hymenoptera and Associated Insects Dedicated to Karl V. Krombein, Memoirs of the Entomological Society of Washington 17: 142ndash;152.).
• Propodeum propodeum:
  the last segment of the thorax
  basalbasal:
  originating at the foundation of a structure
  area without strong pits or posterior carinacarina:
  a clearly defined ridge or keel, not necessarily high or acute; usually appears on bees as simply a raised line
  across entire margin.
• Scutellum scutellum:
  shield shaped plate behind scutum
  with large, blunt laterallateral:
  relating, pertaining, or attached to the side
  projections (Michener 1996Michener 1996:
  Michener, C.D. 1996. The first South African dioxyine bee and a generic review of the tribe Dioxyini (Hymenoptera, Megachilidae). Contributions on Hymenoptera and Associated Insects Dedicated to Karl V. Krombein, Memoirs of the Entomological Society of Washington 17: 142ndash;152.).
• Female 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
  absent.
• Female mandiblemandible:
  bee teeth, so to speak, usually crossed and folded in front of the mouth
  slender and bidentatebidentate:
  having two teeth
  .
• Female tarsal claws bifidbifid:
  divided into two branches; forked
  .

May be confused with

Metadioxys resembles Dioxys in body form, but Dioxys can be differentiated by the lack of the transverse basalbasal:
originating at the foundation of a structure
carina on the labrumlabrum:
part of the head abutting the clypeus, folds down in front of the mouthparts
and the rounded front coxacoxa:
the basal segment of the leg
.

Known invasives

There are no known invasives.

Host associations

Metadioxys are cleptoparasiticcleptoparasitic:
bees that lay their eggs in the nest cells of bees in other genera. Their larvae depend on the pollen provided by their host. Since cleptoparasitic bees don't provision their own nests, and instead depend on the pollen collected by their host, the females lack pollen collecting hairs. This often gives them a wasp-like appearance.
bees, and females do not gather pollen from flowers since the larvaelarvae:
active immature form of an insect, especially one that differs greatly from the adult and forms the stage between egg and pupa
develop parasitically on their host’s pollen provisions (Michener 2007Michener 2007:
Michener, C.D. 2007. The Bees of the World (2nd ed.). Johns Hopkins University Press, Baltimore and London, 953 pp.). They will, however, visit flowers, such as Vitex agnus-castus (Lamiaceae) for nectar (Khodaparast and Monfared 2012Khodaparast and Monfared 2012:
Khodaparast, R. and A. Monfared. 2012. A survey of bees (Hymenoptera: Apoidea) from Fars Province, Iran. Zootaxa 3445: 37ndash;58.). Metadioxys are known to parasitize other bees in the family Megachilidae (Michener 2007Michener 2007:
Michener, C.D. 2007. The Bees of the World (2nd ed.). Johns Hopkins University Press, Baltimore and London, 953 pp.).

Nesting behavior

Metadioxys are known cleptoparasites of bees in the family Megachilidae (Michener 2007Michener 2007:
Michener, C.D. 2007. The Bees of the World (2nd ed.). Johns Hopkins University Press, Baltimore and London, 953 pp.). Host selection boundaries, however, are not well understood. In general for bees within the Dioxyini tribe, the female parasite often spends time around the preferred floral resources of its host to locate them. Once a host nest is found, an egg is laid inside a cell as it is being provisioned by the host female (Rozen and Favreau 1967Rozen and Favreau 1967:
Rozen Jr. J.G. and M.S. Favreau. 1967. Biological notes on Dioxys pomonae pomonae and on its host, Osmia nigrobarbata (Hymenoptera: Megachilidae). Journal of the New York Entomological Society 75: 197ndash;203.), or is injected into the cell after it has been sealed off (Rozen and Özbek 2005). After hatching from the egg, the active larvalarva:
active immature form of an insect, especially one that differs greatly from the adult and forms the stage between egg and pupa
uses its pointed mandibles to destroy the host egg or larvalarva:
active immature form of an insect, especially one that differs greatly from the adult and forms the stage between egg and pupa
(Rozen and Özbek 2004). The larvalarva:
active immature form of an insect, especially one that differs greatly from the adult and forms the stage between egg and pupa
retains the somewhat modified “ hospicidalhospicidal:
the early instars of clepoparasitic bees, which have been oviposited into complete brood cells of another species. When the early instars develop, they kill off the developing individual that was originally occupying the brood cell.
” body form for multiple instars before molting into a more ordinary grub-like form where it feeds on the pollen stores of its host (Rozen and Özbek 2004).

Distribution

Metadioxys ranges from Morocco and Greece through southwestern Asia to Uzbekistan (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

Khodaparast, R. and A. Monfared. 2012. A survey of bees (Hymenoptera: Apoidea) from Fars Province, Iran. Zootaxa 3445:37-58.

Michener, C.D. 1996. The first South African bee and generic review of the tribe Dioxyini (Hymenoptera, Megachilidae). Memoirs of the Entomological Society of Washington 17:142-152.

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

Rozen Jr. J.G., and M.S. Favreau. 1967. Biological notes on Dioxys pomonae pomonae and on its host, Osmia nigrobarbata (Hymenoptera: Megachilidae). Journal of the New York Entomological Society 75:197-203.

Rozen Jr. J.G. and H. Özbek. 2004. Immature Stages of the cleptoparasiticcleptoparasitic:
bees that lay their eggs in the nest cells of bees in other genera. Their larvae depend on the pollen provided by their host. Since cleptoparasitic bees don't provision their own nests, and instead depend on the pollen collected by their host, the females lack pollen collecting hairs. This often gives them a wasp-like appearance.
bee Dioxys cincta (Apoidea: Megachilidae: Megachilinae: Dioxyini). American Museum Novitates 3443:1-12.

Rozen Jr. J.G. and H. Özbek. 2005. Egg deposition of the cleptoparasiticcleptoparasitic:
bees that lay their eggs in the nest cells of bees in other genera. Their larvae depend on the pollen provided by their host. Since cleptoparasitic bees don't provision their own nests, and instead depend on the pollen collected by their host, the females lack pollen collecting hairs. This often gives them a wasp-like appearance.
bee Dioxys cincta (Hymenoptera: Apoidea: Megachilidae). Journal of the Kansas Entomological Society 78:221-226.