Megachile (Phaenosarus)

Taxonomy

Family: Megachilidae
Subfamily: Megachilinae
Tribe: Megachilini
Genus: Megachile Latreille, 1802
Subgenus: Phaenosarus Mitchell, 1934
Common name: none

Overview

Megachile (Phaenosarus) bees have almost entirely black integument with reddish tegula and white to ochre hairs (Mitchell 1936). Females range in body length from 14–18 mm, and males range in body length from 13–15 mm (Mitchell 1936). This subgenus was previously synonymized with Megachile (Xanthosarus), but it was reestablished as a subgenus by Gonzalez et al. (2019).

Diagnostic characteristics

(modified from Mitchell 1936)

May be confused with

Megachile (Phaenosarus) is often very similar to Megachile (Xanthosarus) in size, coloration, five-toothed mandibles (in females), and the expanded front tarsi of the males (Mitchell 1936; Michener 2007). Megachile (Phaenosarus) females can be differentiated from Megachile (Xanthosarus) by the appressed pubescence on the apical half of T6 and the length of S6, which extends slightly beyond the apex of the T6 (Mitchell 1936). Male Megachile (Phaenosarus) can be differentiated by the presence of a small median tubercle on the apical margin of S4 (Mitchell 1936).

Host associations

Megachile (Phaenosarus) fortis has been observed visiting flowers of Asteraceae, and they are believed to be valuable pollinators of commercial sunflowers (Helianthus annuus) (Neff and Simpson 1991; Sheffield et al. 2014).

Nesting behavior

Megachile (Phaenosarus) constructs nests cells primarily from leaf pieces (Neff and Simpson 1991). Megachile (Phaenosarus) fortis excavate nests in hard-packed, level soil (Hicks 1926; Eickwort et al. 1981, Neff and Simpson 1991). Their nests contain between 1 and 9 cells (Neff and Simpson 1991). Megachile fortis have been observed displaying territorial behavior, whereby they hover briefly and then pounce on the other male bees (regardless of species) (Neff and Simpson 1991).

Diversity

Megachile (Phaenosarus) is a small subgenus of two species: M. agustini and M. fortis (Mitchell 1936; Trunz et al. 2016).

Known invasives

There are no known invasives.

Distribution

Megachile (Phaenosarus) is a North American subgenus found from Mexico to Canada (Estrada 1992; Vergara and Ayala 2002; Sheffield et al. 2014). This group is widely distributed in the U.S. throughout Utah, Colorado, Arizona, New Mexico, South Dakota, Kansas, Louisiana, Nebraska, and Iowa (Mitchell 1936).

Distribution
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<p><em>Megachile subfortis </em>female face, photo: Chelsey Ritner</p>
Megachile subfortis female face, photo: Chelsey Ritner
<p><em>Megachile subfortis </em>female lateral habitus, photo: Chelsey Ritner</p>
Megachile subfortis female lateral habitus, photo: Chelsey Ritner
<p><em>Megachile subfortis </em>female abdomen, photo: Chelsey Ritner</p>
Megachile subfortis female abdomen, photo: Chelsey Ritner
<p><em>Megachile subfortis </em>male face, photo: Chelsey Ritner</p>
Megachile subfortis male face, photo: Chelsey Ritner
<p><em>Megachile subfortis </em>male lateral habitus, photo: Chelsey Ritner</p>
Megachile subfortis male lateral habitus, photo: Chelsey Ritner
<p><em>Megachile subfortis </em>male abdomen, photo: Chelsey Ritner</p>
Megachile subfortis male abdomen, photo: Chelsey Ritner
<p><em>Megachile agustini</em> male sterna, photo: Colleen Meidt</p>
Megachile agustini male sterna, photo: Colleen Meidt