Little fire ants (LFA) may be tiny, but they pack a powerful sting. Native to South America, these speck-sized invaders have hitchhiked across the Pacific, hidden in imported goods, establishing new populations in islands like Hawaiʻi. Much smaller than the average ant, LFA are about as long as a penny is thick.

LFA are considered one of the World’s 100 Worst Invasive Species (IUCN Invasive Species Specialist Group), because of their ability to reach very high numbers, to the point where people and animals can’t avoid stings. Without the competition and predators that could keep their numbers in check, they are invading houses, yards, agricultural fields, and forests.  They’re also terrible at hanging on, so they easily fall off plants and trees when bumped by people or animals. Unsuspecting victims of the “ant rain” are left with painful stings.

Little fire ants may have reached our shores, but we can’t treat it like “just another ant.”  It’s up to each of us to Spot The Ant and Stop the Ant.

Little Fire Ant

Wasmannia auropunctata

Wasmannia auropunctata (little fire ant); adult. Smithfield, Cairns, Queensland, Australia. July, 2006. Museum specimen. Body length approx. 1.5 mm, reddish to golden brown. Workers are monomorphic. Antennae consist of 11 segments, the last two forming a distinct club. Antennal scrobes are well marked and extend almost to the occipital border. Head and thorax are heavily sculptured with grooves and pits. Epinotal spines are set close together at the base, strongly diverging and slightly incurved when seen from above. Node of the petiole is rectangular in profile and higher than the post-petiole. The erect body hairs are long, coarse and rather sparse. The strongly quadrate lateral profile of the petiolar node is unique to this species.

Tropical Fire Ant

Solenopsis Geminata (Fabricius) 

Hung et al. (1977) provided a key for the identification of fire ants in Texas, USA. S. geminata worker ants have two nodes between the thorax and abdomen, distinct compound eyes, ten segments on the antennae with two segments forming a club, no spines on the propodeum and are over 2 mm long. Major worker ants have a deep groove on the vertex of the head, mandibles without teeth and are entirely black, with a short antennal scape reaching half-way to the vertex (Vinson et al., 2003).

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