Resin Bees (*Megachile* spp.) are a type of solitary bee belonging to the **Leafcutter Bee** family, sometimes specifically referring to those that utilize plant resins in their nest construction. The conflict is **negligible nuisance**: they are non-aggressive, solitary, and highly beneficial pollinators. The only possible conflict is minor cosmetic damage, where they may chew or scrape soft wood, putty, or plant pith to create or modify a suitable nesting tunnel.
Taxonomy and Classification
Resin Bees belong to the Family Megachilidae (Solitary Bees). They are solitary, meaning each female provisions her own nest and does not live in a colony.
Physical Description
Adults are 6-15 mm long.
- Adult (Key ID): Robust, often dark body; females carry pollen on a dense brush of hairs (scopa) on the underside of their abdomen, giving them a fuzzy appearance.
- Nesting ID: They nest in existing holes (old beetle galleries, hollow stems, drill holes) and cap the cells with resin, mud, or leaf pieces.
- Sting ID: Non-aggressive; only sting if severely handled or stepped on (minor pain).
- Conflict: None to Negligible Nuisance; Highly Beneficial.
Distribution and Habitat
Found globally. Habitat is any area containing suitable nesting cavities and flowering plants for pollen/nectar collection. They are commercially managed as crop pollinators.
Behavior and Conflict
The conflict is minor and accidental.
- Tunnel Excavation: In some cases, females will chew out pith or soft/rotted wood to enlarge a cavity, causing minor damage to decking, railings, or siding.
- Pollination (Key Role): They are highly efficient pollinators, often “buzz-pollinating” certain crops.
Management and Prevention
Management is Conservation. To manage and prevent resin bees—especially invasive species like the sculptured resin bee—focus on blocking nesting spots and reducing attractants. Seal cracks, holes in wood, and wall gaps where they may nest, and plant native plants to support local bees. Resin bees often take over carpenter bee holes and can push out native species, so reporting sightings can help track their spread.
If resin bees are already present, wait until late summer or fall (after the bees have emerged) to seal tunnels. Carpenter bee traps may help reduce activity. Pesticides should only be used as a last resort, and local extension offices can advise on safe options that protect native bees.
- Allow them to continue nesting; they do not require control and are valuable biological assets.
- Sealing up drill holes in decks or structural wood to prevent access to specific nesting sites.
Conservation and Research
Research focuses on optimizing their management for commercial pollination, especially in crops like alfalfa and orchard fruits.