Megachile inermis

Provancher, 1888

Unarmed Leafcutter Bee

Megachile inermis is a solitary leafcutter bee described by Provancher in 1888. Unlike many Megachile that use pre-existing cavities, this excavates its own nesting tunnels in decayed poplar wood. It has been recorded from trap-nest studies in Saskatchewan, Manitoba, and Wisconsin, with a notable male-biased sex ratio in rearings.

Megachile inermis by Sierra Williams and Elizabeth Garcia. Used under a Public domain license.

Megachile inermis, female, face 2012-07-13-17.48.00 ZS PMax (8131694027) by USGS Native Bee Inventory and Monitoring Laboratory from Beltsville, USA. Used under a Public domain license.

Megachile inermis1 by Sierra Williams and Elizabeth Garcia. Used under a Public domain license.

Pronunciation

How to pronounce Megachile inermis: /ˌmɛɡəˈkaɪli ɪˈnɜrmɪs/

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 its nesting : excavates tunnels directly into decayed wood rather than using pre-existing holes or borer tunnels. Specific morphological diagnostic features are not documented in available sources.

Images

Habitat

Burnt-over or waste poplar stands; decayed poplar trees with sufficient softening to allow excavation. Nests in cracks, crevices, or exposed ends of logs. Accepts trap-nests with 5/16-inch (approximately 8mm) diameter holes; did not use 1/4-inch holes in one study.

Distribution

North America: recorded from Saskatchewan, Manitoba, Wisconsin, and Vermont.

Life Cycle

Nests contain 2–7 (average 4.2 cells per nest). Development occurs in individual cells within excavated tunnels. Rearings from multiple nests produced only males (13 males, 0 females), suggesting either male-biased sex ratio or differential survival in trap-nest conditions.

Behavior

Excavates own nesting tunnels in decayed poplar wood starting from cracks, crevices, or exposed log ends. Does not use existing borer tunnels.

Ecological Role

Presumed ; specific plant associations not documented.

Similar Taxa

Megachile fidelisBoth are leafcutter bees in the same , but M. fidelis uses pre-existing cavities and cuts leaf pieces for nest lining, while M. inermis excavates its own tunnels in decayed wood.
Megachile plutoBoth are Megachile , but M. pluto is dramatically larger (world's largest ), nests in active mounds lined with resin, and is restricted to Indonesian islands.

More Details

Nesting biology note

This shows flexible nesting , using both naturally decayed wood and artificial trap-nests of appropriate diameter. The failure to use 1/4-inch holes but acceptance of 5/16-inch holes suggests specific diameter preferences.