Megachile (Ptilosarus)

Taxonomy

Family: Megachilidae
Subfamily: Megachilinae
Tribe: Megachilini
Genus: Megachile Latreille, 1802
Subgenus: Ptilosarus Mitchell, 1943
Common name: none

Overview

Megachile (Ptilosarus) are bees with black integument and dense, short, yellow to golden pubescence on the most apical terga. They range in body length from 7–10 mm (Michener 2007).

Diagnostic characteristics

(modified from Michener 2007; Gonzalez 2008)

Forewing with darkened costal margin.
Female mandible is four-toothed with cutting edges in the second and third tooth interspaces.
Female with strong preoccipital carina behind the gena laterally and across the vertex.
Female thoracic venter, leg bases, and S2 with dense, plumose pubescence.
Female thorax and abdomen are densely and minutely punctate with sub-erect tomentum.
Male mandible with 3–4 teeth.
Male front tarsi are slender and black.
Male T6 preapical carina with two small teeth or projections.
Male front coxa lacks a spine.

May be confused with

Megachile (Ptilosarus) may be confused with bees within the subgenera Megachile (Ptilosaroides) as both have similar short, dense pubescence on the apical terga and darkened forewing costal margins (Michener 2007). Both sexes of Megachile (Ptilosarus) can be differentiated from Megachile (Ptilosaroides) by the presence of strong preoccipital carina that is present both dorsally and laterally. Additionally, Megachile (Ptilosarus) females can be differentiated by the plumose hairs on the ventral side of the thorax and leg bases, and males can be differentiated by the lack of a spine on the front coxa (Michener 2007).

Host associations

Megachile (Ptilosarus) have been observed visiting Asteraceae, Malvaceae, and Piperaceae (Raw 2007). Megachile (Ptilosarus) exhibit a unique behavior of crawling up and down the spike-like inflorescence of pepper vines (Piper sp.). As they crawl, they move their abdomen from side to side, most likely to enhance the amount of pollen collected (Michener 2007). These bees have plumose hairs on the underside of their thorax and at the base of their legs that may be a specialization for collecting pollen from these plants (Michener 2007; Gonzalez 2008).

Nesting behavior

Megachile (Ptilosarus) nests in pre-existing cavities using leaf fragments to form the nest cells (Vélez et al. 2020). Megachile (Ptilosarus) have been observed nesting in decaying wood, in empty cavities within active termite nests, and in abandoned solitary bee (Ptilothrix plumata and Diadasina distincta) nests (Martins and Almeida 1994; Almeida et al. 1997; Vélez et al. 2020).

Diversity

Megachile (Ptilosarus) consists of 13 described species; none are known to occur in the U.S. or Canada (Raw 2007; Gonzalez 2008).

Known invasives

There are no known invasives.

Distribution

Megachile (Ptilosarus) are found predominantly in tropical areas of North and South America, where they range from Veracruz, Mexico to Misiones, Argentina (Michener 2007).

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