**Tunnel Carpenter Bees** (referring to the **Small Carpenter Bee**—*Ceratina* species, or other small species) are small, often metallic green or black bees that bore into the pith (soft center) of dead or dying plant stems. The conflict is primarily **minor stem damage and nuisance**: they nest by excavating tunnels in plant stems (e.g., raspberry, rose, sumac) and laying eggs inside. While the damage is minor, it can occasionally cause **flagging or dieback** of the tip of a susceptible cane, creating a slight aesthetic issue.
Taxonomy and Classification
Small Carpenter Bees belong to the order Hymenoptera, family Apidae. They undergo complete metamorphosis. They are solitary bees, meaning they do not live in colonies, and the female provisions the nest alone.
Physical Description
Adult Bees are minute, 1/8 to 1/4 inch long.
- **Appearance (Key ID):** Small, slender, often metallic blue-green or black, nearly hairless body. They lack the striking yellow/black markings of larger carpenter bees.
- **Behavior (Key ID):** They excavate a tunnel in the pith of stems, creating a linear series of cells separated by pith material. They are **beneficial pollinators**.
- **Damage Sign (Key ID):**
- **Hole:** A small, neat, circular hole bored into the center of a cut or broken cane or twig, often near the tip.
- **Pith Removal:** Tunneling and removal of the soft central pith material inside the stem.
- **Conflict:** Minor stem damage and aesthetic loss (generally considered harmless).
Distribution and Habitat
Small Carpenter Bees are found globally. Their habitat is the soft, pithy stems of small shrubs and perennial plants.
Behavior and Conflict
The conflict is minor and overshadowed by their benefit.
- **Pollination:** They are important native pollinators in gardens and natural areas.
- **Minimal Damage:** They only utilize dead, dying, or pruned stems and are not a threat to healthy woody structures (unlike the large *Xylocopa* carpenter bees).
Management and Prevention
Management is **tolerance and conservation**. No control is recommended.
- Allow the bees to utilize the pithy stems, as they are beneficial and cause no significant harm.
- If damage is unwanted, simply prune out the affected tip of the cane.
Conservation and Research
Small Carpenter Bees are highly conserved as native pollinators. Research focuses on their role in providing pollination services and managing their populations for biodiversity.