Chelostoma rapunculi

Leaf-cutter Bee
Chelostoma rapunculi

Leaf-cutter Bee Chelostoma rapunculi female on Culver's Root July 20, 2015, Leamington, Ontario.
Leaf-cutter Bee Chelostoma rapunculi female on Culver’s Root July 20, 2015, Leamington, Ontario.

From Europe and Asia, introduced to New York as early as 1962. In Ontario by 2005.

Identification:
Head: Black, squarish, smooth (few punctures) but not shiny. Above mouth area (clypeus) slightly raised (convex); mouth area more concave. Mandibles black, short, with 3 teeth. Cheeks as wide as eye width. Female has some white hair on mouth area and along inner eye margins. Male has hair on lower cheeks; hair on mouth and below mouth can be quite dense.

Leaf-cutter Bee Chelostoma rapunculi female on Culver's Root July 22, 2015, Leamington, Ontario.
Leaf-cutter Bee Chelostoma rapunculi female on Culver’s Root July 22, 2015, Leamington, Ontario.

Antenna: Black, short, 10 segments on female, 11 on male. Male antenna do not appear much longer than female’s.
Thorax: Black, smooth (few punctures), not shiny; slightly raised with some white hair around edges. White hair tufts before wing bases. Segment 3 (propodeum) very short, slanted downward. Male has dense white hair along lower half of thorax sides.

Wings: Wing knobs (tegulae) black, wings dusky, darker on last half.
Legs: Black with white pile stripes and a line of white fringe on along underside of legs. Feet sometimes have more yellowish hair.

Leaf-cutter Bee Chelostoma rapunculi male on Sumac leaf June 30, 2008, Wheatley, Ontario.
Leaf-cutter Bee Chelostoma rapunculi male on Sumac leaf June 30, 2008, Wheatley, Ontario.

Abdomen: Black with white hair band on each lower edge of segments. Segments slightly constricted (spare tire-like). Segment 1 only slightly concave at base. Underside of female covered with white hair (pollen basket). Male has obvious long projection with rounded, slanted tip on underside of segment 2; last segment has 3 lobes, ends squarish (truncate).

Leaf-cutter Bee Chelostoma rapunculi male on Musk Mallow July 02, 2013, Wheatley, Ontario.
Leaf-cutter Bee Chelostoma rapunculi male on Musk Mallow July 02, 2013, Wheatley, Ontario.

Similar Species: Hoplitis species have oddly-shaped antenna with pointed tips. Heriades species have rough-textured skin (dense punctures).
Chelostoma campanularum and C. philadelphi have no hair bands on abdomen.

Size: 8 to 11 mm.

Habitat: Forests and forest edges.

Food: Nectar from flowers such as Wild Geranium, Bellflowers, Viper’s Bugloss Echium vulgare, Musk Mallow Malva moschata. Must have Campanula species pollen for larvae.

Flight Time: June to end of July.

Life Cycle: Nests in old wood stumps and fence posts with beetle tunnels, and hollow stems. Females must have pollen from Campanula flowers to feed young. Males often sleep in these flowers. One generation per year.

Comments: Listed for southern Ontario – Niagara and Toronto area. Essex County – photos.

For information on synonyms, references and type specimens see next page

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