**Urban Ants** refers to the numerous ant species (*Formicidae* family) that thrive in human-modified environments, particularly those that invade structures or lawns. Key pests include the **Argentine Ant** (*Linepithema humile*), **Pharaoh Ant** (*Monomorium pharaonis*), and **Pavement Ant** (*Tetramorium caespitum*). The conflict is **nuisance, food contamination, and structural damage**: they infest food, contaminate sterile environments (hospitals), damage electrical systems, and undermine sidewalks and foundations with their nesting activity.
Taxonomy and Classification
Ants belong to the Order Hymenoptera (Ants, Wasps, Bees). They are social insects that undergo complete metamorphosis and live in complex, hierarchical colonies.
Physical Description
Workers are small, 1.5\text{ mm} to 5\text{ mm} long.
- **Worker (Key ID):** Distinctive, three-part body (head, thorax, abdomen) connected by a narrow petiole (waist), which may have one or two nodes.
- **Damage ID:** Trails of ants foraging indoors; presence of fine soil particles (mounds) along structural edges; food contamination.
- **Behavior ID:** Many urban species form large **supercolonies** (e.g., Argentine Ants) that are difficult to manage locally.
- **Conflict:** Structural, Public Health, Nuisance.
Distribution and Habitat
Cosmopolitan (found worldwide). Habitat is indoors (voids, walls, under slabs) and outdoors (sidewalk cracks, lawns, under debris). They seek food, water, and stable nesting temperatures.
Behavior and Conflict
The conflict is driven by their numbers and mobility.
- **Foraging:** They exploit human food and sugary products (honeydew from aphids), leading to rapid trail formation into homes.
- **Structure Damage:** Pavement Ants excavate soil, undermining pavers and slabs; Carpenter Ants excavate wood (structural damage).
Management and Prevention
Management is **Integrated Pest Management (IPM) focusing on the colony**.
- Use of slow-acting, non-repellent **insecticidal baits** (liquid or gel) that workers take back to the nest to kill the queen and larvae.
- Targeted application of non-repellent liquid insecticides to exterior foraging trails and entry points.
- Sealing foundation cracks, window frames, and utility entry points to block ingress.
Conservation and Research
Research focuses on the aggressive competitive behavior of invasive species (like the Argentine Ant) and developing better bait formulations that can manage large, complex supercolonies.