**Wedge-shaped Beetles** (Family Mordellidae, also called **Tumbling Flower Beetles**) are small, distinctive beetles characterized by their sharply tapering, **wedge-shaped** abdomen and body, and their habit of running, jumping, or ‘tumbling’ rapidly when disturbed. The conflict is **minor larval wood damage and pollen nuisance**: the larvae feed in decaying wood (beneficial role) or occasionally bore into the pith of dead stems. The adults are non-damaging but can be a minor nuisance when found feeding on pollen in the flowers of crops and ornamentals.
Taxonomy and Classification
Wedge-shaped Beetles belong to the Order Coleoptera (Beetles). They undergo complete metamorphosis. The adults are commonly found on flowers.
Physical Description
Adults are small, 3 mm to 10 mm long.
- **Adult (Key ID):** Humpbacked, often black or dark brown; the head is tucked beneath the thorax; the rear end tapers dramatically to a sharp point (the wedge shape).
- **Behavior ID (Key):** Highly active and rapid movers; they frequently jump or tumble from flowers when approached, making them difficult to catch.
- **Larva (Key ID):** Slender, soft-bodied, cylindrical larva found feeding inside decaying wood or plant stems.
- **Conflict:** Minor Nuisance, Minor Plant Damage.
Distribution and Habitat
Found worldwide. Habitat includes meadows, gardens, and woodlands. Adults are found feeding on the pollen of open flowers (e.g., daisies, Queen Anne’s lace), while larvae are found in dead plant tissue or wood.
Behavior and Conflict
The conflict is their non-pest status, sometimes leading to misidentification.
- **Pollinators:** The adults are considered minor beneficial pollinators of some plant species as they move between flowers.
- **Decomposers:** The larvae play a beneficial role in breaking down dead wood.
Management and Prevention
Management is **Toleration**.
- As they are generally beneficial and do not damage live, healthy plant tissue, no control measures are needed or recommended.
Conservation and Research
Research focuses on their unique morphology and rapid movement, which is an adaptation to escape predation while feeding on exposed flower heads.