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 apical bands on the terga. They range in body length from 10–11 mm (Michener 2007).

Diversity

Metadioxys consists of three species (Michener 2007); none are known to occur in the U.S. or Canada.

Diagnostic characteristics

(modified from Michener 2007 unless otherwise stated)

May be confused with

Metadioxys resembles Dioxys in body form, but Dioxys can be differentiated by the lack of the transverse basal carina on the labrum and the rounded front coxa.

Known invasives

There are no known invasives.

Host associations

Metadioxys are cleptoparasitic bees, and females do not gather pollen from flowers since the larvae develop parasitically on their host’s pollen provisions (Michener 2007). They will, however, visit flowers, such as Vitex agnus-castus (Lamiaceae) for nectar (Khodaparast and Monfared 2012). Metadioxys are known to parasitize other bees in the family Megachilidae (Michener 2007).

Nesting behavior

Metadioxys are known cleptoparasites of bees in the family Megachilidae (Michener 2007). 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 1967), or is injected into the cell after it has been sealed off (Rozen and Özbek 2005). After hatching from the egg, the active larva uses its pointed mandibles to destroy the host egg or larva (Rozen and Özbek 2004). The larva retains the somewhat modified “hospicidal” 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 2007).

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<p><em>Metadioxys graeca</em> male face, photo: C. Ritner © Division of Entomology, University of Kansas Biodiversity Institute</p>
Metadioxys graeca male face, photo: C. Ritner © Division of Entomology, University of Kansas Biodiversity Institute
<p><em>Metadioxys graeca</em> male lateral habitus, photo: C. Ritner © Division of Entomology, University of Kansas Biodiversity Institute</p>
Metadioxys graeca male lateral habitus, photo: C. Ritner © Division of Entomology, University of Kansas Biodiversity Institute
<p><em>Metadioxys graeca </em>male abdomen, photo: C. Ritner © Division of Entomology, University of Kansas Biodiversity Institute</p>
Metadioxys graeca male abdomen, photo: C. Ritner © Division of Entomology, University of Kansas Biodiversity Institute
<p><em>Metadioxys graeca</em> male S6 with emargination, photo: C. Ritner © Division of Entomology, University of Kansas Biodiversity Institute</p>
Metadioxys graeca male S6 with emargination, photo: C. Ritner © Division of Entomology, University of Kansas Biodiversity Institute