Xenostelis

Taxonomy

Family: Megachilidae
Subfamily: Megachilinae
Tribe: Anthidiini
Genus: Xenostelis Baker, 1999
Subgenera: none
Common name: none

Overview

Xenostelis are small (5–6 mm) black bees with reddish-orange legs, yellow maculations on the sides of 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
and T2T2:
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 orange-yellow across T5T5:
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 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
(Baker 1999Baker 1999:
Baker, D.B. 1999. On new stelidine bees from S.W. Asia and N.W. Africa, with a list of the Old-World taxa assigned to the genus Stelis Panzer, 1806 (Hymenoptera, Apoidea, Megachilidae). Deutsche Entomologische Zeitschrift, 46: 231ndash;242.; Michener 2007Michener 2007:
Michener, C.D. 2007. The Bees of the World (2nd ed.). Johns Hopkins University Press, Baltimore and London, 953 pp.). The genus is based on one female specimen (Michener 2007Michener 2007:
Michener, C.D. 2007. The Bees of the World (2nd ed.). Johns Hopkins University Press, Baltimore and London, 953 pp.).

Diversity

Xenostelis consists of one species, X. polychroma (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 Baker 1999Baker 1999:
Baker, D.B. 1999. On new stelidine bees from S.W. Asia and N.W. Africa, with a list of the Old-World taxa assigned to the genus Stelis Panzer, 1806 (Hymenoptera, Apoidea, Megachilidae). Deutsche Entomologische Zeitschrift, 46: 231ndash;242. unless otherwise stated)

• Arolia present but reduced.
• First flagellar segment broader than long.
• Juxtantennal carinacarina:
  a clearly defined ridge or keel, not necessarily high or acute; usually appears on bees as simply a raised line
  absent.
• Middle tibiatibia:
  the segment of the leg, between the femur and the tarsus
  with two apicalapical:
  near or at the apex or end of any structure
  spines (Michener 2007Michener 2007:
  Michener, C.D. 2007. The Bees of the World (2nd ed.). Johns Hopkins University Press, Baltimore and London, 953 pp.).
• Scutellum scutellum:
  shield shaped plate behind scutum
  sub-truncate and overhanging metanotummetanotum:
  the posterior dorsal segment of the thorax, behind the scutellum
  .
• Tegula tegula:
  the usually oval, small shield-like structure carried at the extreme base of the wing where it attaches to the body
  enlarged posteriorly, nearly as broad as long posteriorly (Michener 2007Michener 2007:
  Michener, C.D. 2007. The Bees of the World (2nd ed.). Johns Hopkins University Press, Baltimore and London, 953 pp.).
• T1 without raised carinacarina:
  a clearly defined ridge or keel, not necessarily high or acute; usually appears on bees as simply a raised line
  between the anterioranterior:
  toward the head or on the head side of a segment being described
  and dorsaldorsal:
  in general, the upper surface
  faces.
• T6 broadly truncatetruncate:
  ending abruptly, or squared off
  .
• 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 (Michener 2007Michener 2007:
  Michener, C.D. 2007. The Bees of the World (2nd ed.). Johns Hopkins University Press, Baltimore and London, 953 pp.).

May be confused with

Xenostelis resembles Afrostelis due to large tegulaetegulae:
the usually oval, small shield-like structure carried at the extreme base of the wing where it attaches to the body
, but can be differentiated by a less elongate thorax and presence of yellow markings.

Known invasives

There are no known invasives.

Host associations

Xenostelis are presumed 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 due to the lack of scopal hairs in the females. They likely 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
of 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 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 a wide variety of flowers for nectar.

Nesting behavior

Nesting behavior is unknown.

Distribution

Xenostelis occurs on the island of Socotra, Yemen (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

Baker, D.B. 1999. On new stelidine bees from S.W. Asia and N.W. Africa, with a list of the Old-World taxa assigned to the genus Stelis Panzer, 1806 (Hymenoptera, Apoidea, Megachilidae). Deutsche Entomologische Zeitschrift, 46:231-242.

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