Leafcutter Bee - Megachile willughbiella

Length 12 to 18 mm. A large leafcutter bee, the males of which have distinctive white flattened front tarsi. Females of this genus can be difficult to identify, even under a microscope. It is the commonest leafcutter bee and the species most likely to be encountered in gardens where it readily uses bee hotels.

See our ID Aid below below for identifying males.

Where a photo is surrounded by a red box it means that it is representative of the species but may not be the actual species described.

Males:

• white, posterior fringe on front tarsi
• front basitarsi not much longer than wide and broader than the tibia tip
• hind tibia and tarsi not swollen and tarsi as long or longer than the tibia

Females:

• wing length 8.5-10.5mm
• orange pollen brush (with few dark hairs on tergites 5 and 6)
• hair brush on the front tarsi only on the basitarsus and hairs approx. 1.5x the width of the tarsus
• hairs on tergite 6 adpressed
• sparce buff hairs on the hind margins of the tergites

Most solitary bees and wasps are difficult to identify, and can rarely be identified from photos taken in the field.  All red-rated records should include a photo or set of photos of the specimen, illustrating the key characters taken from a standard key, which should also be referenced (e.g. ‘Falk, 2015’).  The full set of key characters are generally not visible in field photos and photos are rarely sharp enough. To aid in the verification of your records, please include face shot, side, top and wings.  The notes should state whether male or female, and explain how the specimen met the key characters.  Although NS may not be able to identify the species even if these reference photos are provided, the photos will be stored with the record and may allow it be identified in future.   Alternatively, NS will accept records identified by a recognised local or national expert, or that have been identified via BWARS’ Facebook https://www.facebook.com/profile.php?id=100065021433202 .  If you have obtained this advice, please note the name of the person/organisation identifying the record in the ‘determiner’ field (e.g. ‘Stuart Roberts, BWARS Facebook’) rather than just a comment of ‘BWARS Facebook’.

Often found in gardens. It nests in sunny, sheltered locations in crevices in dead wood or in the ground, sometimes using the soil in flower pots.

June to August.

Female Megachile bees construct nests of larval cells from leaves and provision each cell with a mixture of pollen and nectar for the young. The larva feed on this food store before overwintering and emerging the following summer.

Common.

Common.