Megachile (Eutricharaea) apicalis Spinola, 1808

Pritchard, Zoe A., Ivie, Michael A., O’Neill, Kevin M. & Delphia, Casey M., 2025, A faunal treatment of the Megachile (Hymenoptera: Megachilidae) of Montana with a key for their identification, Zootaxa 5683 (1), pp. 1-51 : 29

Megachile (Eutricharaea) apicalis Spinola, 1808

Megachile apicalis Spinola, 1808: 259 .

Megachile (Eutricharaea) apicalis ; Mitchell 1962: 120. Hurd 1979: 2057. Cooper 1984: 225. Sheffield et al. 2011: 29. Kuhlman and Burrows 2017: 12 . Reese et al. 2018: 21 . Delphia et al. 2019a: 24 . Sheffield and Heron 2019: 69.

Megachile virginiana Mitchell, 1926a: 113 .

Diagnosis. The female of M. apicalis can be identified by the white apical setal bands on S2–6 ( Fig. 6A ), black scopal setae on S5, and lateral, ovate fovea on T2 and T3. Females of M. apicalis are most similar to M. rotundata , which have white scopal setae on S5 and lateral, ovate fovea on T2 only. The male of M. apicalis can be distinguished by the lateral, ovate fovea on T2 and T3. Males of M. apicalis are most similar to M. rotundata , which have lateral, ovate fovea on T2 only.

Notes. Megachile apicalis is an accidentally introduced species in the United States, first collected in Montana in 2013 from localities in Deer Lodge, Sanders, and Lake Counties. It was first documented in the literature by Kuhlman & Burrows (2017). This species may contribute to pollination of the invasive yellow star-thistle ( Centaurea solstitialis ), though not as strongly as A. mellifera ( Barthell et al. 2001) . Megachile apicalis is currently present in western Montana but is expected to spread further ( Fig. 1C ). It is established on both coasts of the U.S. and seems to be moving into Montana from the Pacific Northwest region (see Discussion: Notes on Megachile (Eutricharaea) rotundata and Introduced Megachile Species ). Photographs, a full morphological description, and notes on the biology of this species can be found in Sheffield et al. (2011).

Figures

FIGURE 1. County-level distribution of each Megachile species in Montana. Females identified as Megachile latimanus/ Megachile perihirta (and data without recorded specimen sexes) are counted here as M. perihirta as they are not distinguishable from one another in Montana. Males identified as Megachile lapponica/Megachile relativa (and data without recorded specimen sexes) are counted here as M. relativa as they are not distinguishable from one another in Montana. Mitchell county records are included on maps but not in specimen counts. Two specimens did not have county-level localities and are not included in maps but are included in specimen counts.

FIGURE 6. Female Megachile characters. (A) Ventral view of metasoma with white apical setal bands on S2–6, (B) Dorsal view of rounded metasoma, widest at T2–3, (C) Dorsal view of subparallel metasoma, (D–H) Anterior view of clypeus: (D) M. apicalis, (E) M. mellitarsis, (F) M. fidelis, (G) M. lippiae, (H) M. coquilletti, (I) Lateral view of mandible gradually tapering in width towards apex, (J) Lateral view of mandible with base square-shaped with parallel sides for a distance as long as wide, then tapering apically, and (K) Lateral view of mandible square basally, with sides parallel for approximately ⅓ the length of mandible, then tapering apically.