Red imported fire ant vs Pavement ant
These two are easy to mix up. Here's how to tell a red imported fire ant from a pavement ant, and whether either one bites or stings.
Red imported fire ant
Solenopsis invicta
Pavement ant
Tetramorium immigrans
≠The key differences
Pavement ants are dark brown to blackish, have 12-segmented antennae with a three-segmented club and fine parallel grooves on the head and thorax, and nest under pavement and stones with small piles of soil rather than large dome mounds.
⚖︎Side by side
| Red imported fire ant | Pavement ant | |
|---|---|---|
| To humans | Painful sting | Non-toxic |
| Size | Workers 2.4-6 mm; queens about 7-9 mm | Workers 2.5-4 mm; queens 6-8 mm |
| Colours | Reddish-brown, Dark brown, Black (gaster in some individuals) | Brown, Dark brown, Black |
| Family | Formicidae | Formicidae |
| Habitat | Open, sunny habitats: lawns, parks, agricultural fields, roadside verges, disturbed ground, and urban green spaces. Nests in soil mound structures. | Urban and suburban areas: cracks in pavement and sidewalks, under stones, curbs, building foundations, lawns and occasionally inside buildings. |
| Range | Native to South America; invasive and established across much of the southeastern United States, parts of the western US, Australia, China, Taiwan, parts of the Caribbean and other regions where they were introduced. | Native to Europe and parts of Asia; introduced and common across North America and other temperate regions worldwide. |
| Active | Active year-round in warm climates; most active spring through fall and during warm parts of the day. | Spring through fall (most active during warm months); workers forage day and night depending on temperature. |
| Pest? | Yes | Yes |
🔍How to spot a red imported fire ant
- Workers reddish-brown to dark red, 2.4-6 mm long; queens larger and darker (about 7-9 mm).
- Two-segmented waist (two nodes) between thorax and abdomen; elbowed antennae with 10 segments ending in a two-segmented club.
- Conspicuous soil mounds without a central entrance hole, often in open, sunny locations.
- Very aggressive: when a mound is disturbed, many workers swarm and sting.
🔍How to spot a pavement ant
- Small workers 2.5-4 mm, uniformly brown to dark brown with a slightly darker gaster.
- Two petiole nodes (two-segmented waist) and two short spines on the rear of the mesosoma.
- Head and thorax show fine parallel sculpturing; antennae with 12 segments and a 3-segmented club.
- Nests in cracks in pavement, along foundations and under stones; look for worker trails at nest entrances.
?Frequently asked questions
What is the difference between a red imported fire ant and a pavement ant?
Pavement ants are dark brown to blackish, have 12-segmented antennae with a three-segmented club and fine parallel grooves on the head and thorax, and nest under pavement and stones with small piles of soil rather than large dome mounds.
Is a red imported fire ant or a pavement ant more dangerous?
Red imported fire ant: Painful sting. Pavement ant: Non-toxic. Workers sting repeatedly, injecting alkaloid venom (solenopsin) that causes immediate burning pain, raised wheals and pustules in many people. Pavement ants do not have dangerous venom.
Identification from photos is never certain: don't handle insects you can't identify, and get medical advice for bites, stings or allergic reactions.