Megachile perihirta

Cockerell, 1898

Western Leafcutter Bee, Western leafcutting bee

Megachile perihirta, commonly known as the Western Leafcutter , is a solitary bee to western North America. It is an important of alfalfa and other , recognized by its distinctive leaf-cutting where females cut circular pieces from leaves to nest . The nests in pre-existing cavities in soil, sand, gravel, or rotting wood, and carries pollen on a located on the underside of the rather than on the hind legs.

Megachile perihirta by the Smithsonian. Used under a CC0 license.

Pronunciation

How to pronounce Megachile perihirta: /ˌmɛɡəˈkaɪli pɛˈraɪhɪrtə/

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

Distinguished from other Megachile by the combination of black body with long whitish- hair below and , mostly bare abdomen with scattered whitish segmental hair, and bright red . Differs from and by carrying pollen on abdominal scopa rather than on hind legs. Separable from other western North Megachile by hair and distribution patterns; M. perihirta has more extensive pale hair than many .

Images

Appearance

Black body with long whitish- hair, denser below the and . Abdomen is mostly bare with scattered whitish hair on each . are clear with black . () on the underside of the abdomen is bright red when loaded with pollen. present: females have scopa for pollen collection, males lack scopa and often have more extensive pale markings.

Habitat

Meadows, orchards, and agricultural fields, particularly alfalfa seed production areas. Nests in pre-existing cavities in sand, gravel, soil, or rotting wood and material. Requires bare ground or suitable cavities for nesting, and diverse flowering plants for foraging.

Distribution

Western North America, ranging from Nebraska to Texas and Mexico, westward to California, and north to British Columbia and Alberta.

Seasonality

active primarily from July to August. One per year with adults living approximately one year.

Diet

feed on nectar. feed on provisions of pollen and nectar deposited in nest . Strongly associated with alfalfa (Medicago sativa) in agricultural settings; also forages on other flowering plants.

Life Cycle

Solitary. Females excavate or occupy pre-existing burrows in soil, sand, gravel, or rotting material. Constructs series of lined with circular leaf fragments cut from plants. Each cell provisioned with pollen-nectar mixture and receives one . develops within cell, consuming provisions. Pupates within cell. emerge following year.

Behavior

Exhibits leaf-cutting : females cut circular or oval pieces from leaves using , then transport these fragments to nest for lining. Carries pollen on rather than leg baskets. Solitary nesting, though small groups may aggregate nesting sites. Effective buzz of alfalfa flowers, tripping keel mechanism to access pollen.

Ecological Role

Principal of alfalfa for commercial seed production in western North America. Contributes to of other flowering plants in meadow and orchard . As a , supports reproductive success and maintains floral structure.

Human Relevance

Managed and encouraged in alfalfa seed production for its superior compared to . Nest blocks and condos provided in agricultural and garden settings to support . Leaf-cutting activity occasionally considered minor nuisance to ornamental plants, though generally tolerated due to pollination benefits.

Similar Taxa

Megachile dentitarsusCo-occurring ground-nesting Megachile in southern Alberta, also important alfalfa ; distinguished by differences in mandibular and tarsal
Megachile rotundata (Alfalfa Leafcutter Bee)Commercially managed alfalfa with similar ; M. perihirta has more extensive pale hair and different western distribution
Apis mellifera (Honey Bee) managed ; differs in social colony structure, corbiculate pollen transport on hind legs, and lack of leaf-cutting

More Details

Pollen Collection

Unlike and , Megachile perihirta carries pollen in a —a dense brush of hairs on the surface of the —rather than in () on the hind legs. This trait is diagnostic for the Megachile and Megachilinae.

Agricultural Significance

Research in southern Alberta identified M. perihirta and M. dentitarsus as the principal of alfalfa, outperforming other Megachile in frequency, abundance, and effectiveness in mixed prairie environments.