Florida Harvester Ant

Pogonomyrmex badius

Florida Harvester Ant (Pogonomyrmex badius): Charcoal Nests, Power-Drill Sting

The Florida Harvester Ant (Pogonomyrmex badius) is a dark rust-red, seed-storing ant of the US Southeast whose sting Justin Schmidt rated 3.

Schmidt pain rating
3 out of 4
Size
Workers about 6–9.5 mm (1/4–3/8 inch), with big-headed majors
Look
Dark rust-red; workers come in several sizes
Range
Florida to North Carolina, west to Louisiana
Diet
Seeds, plus insects and other arthropods
Conservation
Not evaluated by the IUCN

Habitat & range

The Florida Harvester Ant lives from Florida north to North Carolina and west into Mississippi and Louisiana. Of the roughly 22 harvester ant species in the United States, it is the only one found east of the Mississippi River. It nests in sand, in open woodland, grassy areas and xeric hammocks, and often on lawns, around gardens and along fire lanes. Florida Harvester Ant appears as an Insecta creature card in Wilder TCG.

How to recognise it

Adults are dark rust-red. Unlike other *Pogonomyrmex*, the workers are strongly polymorphic: they range from about 1/4 to 3/8 inch (roughly 6 to 9.5 mm), and the major workers have a disproportionately large head. Like most harvester ants it has a psammophore, a basket of long hairs under the head used to carry sand, though in this species it is poorly developed. The waist has two segments.

A deep, charcoal-decorated nest

The mound itself is low and flat, 30 to 60 cm across, and is often covered with small pebbles or pieces of charcoal from burned areas; the purpose of the decoration is poorly understood. Underground, mature nests are usually 2.5 to 3 m deep, with seeds stored 40 to 100 cm down in large, flat granaries. Young workers stay deep in the nest and move closer to the surface as they age, taking on riskier jobs such as maintaining the nest, defending it and foraging. Walter Tschinkel studied the architecture by pouring plaster, or molten zinc or aluminium, into nest entrances and digging out the casts. A colony has a single queen, and one colony was observed to last at least 19 years.

Seed harvesting

Workers gather seeds that have fallen to the ground and also pick them straight from plants, husk them and dump the chaff on trash heaps at the edge of the mound. Recorded seeds include ragweed, crabgrass, sedge and evening primrose. They also regularly take insects and other arthropods.

The sting

Justin O. Schmidt rated the sting a 3 on his 4-point scale and described it as: "Bold and unrelenting. Somebody is using a power drill to excavate your ingrown toenail." (Schmidt, *The Sting of the Wild*, Johns Hopkins University Press, 2016). The ant is not aggressive and, in the words of University of Florida entomologists, "almost has to be forced to sting", but the pain lasts longer than usual for ant stings. Its venom has an LD50 of 0.42 mg/kg in mice (Schmidt and Blum, 1978), several times as lethal as honey bee venom.

Conservation

*Pogonomyrmex badius* has not been evaluated for the IUCN Red List.

Fun facts about Florida Harvester Ant

  • It is the only harvester ant found east of the Mississippi River.
  • Unusually for its genus, its workers come in several sizes; the biggest, called majors, have huge heads.
  • Colonies often cover the nest mound with small pebbles or bits of charcoal from burned ground, and nobody knows why.
  • Mature nests reach 2.5 to 3 m deep, with seeds stored in flat granaries 40 to 100 cm underground.
  • To map its nests, biologist Walter Tschinkel poured molten zinc or aluminium into the entrances to make metal casts.
  • One colony was observed to live at least 19 years.

Florida Harvester Ant vs Maricopa Harvester Ant

The Maricopa harvester ant's more toxic venom wins this card battle.

There is no record of these two meeting: the Florida harvester ant is the only harvester ant east of the Mississippi, while the Maricopa harvester ant lives in the American Southwest. This is a Wilder comparison of two seed-harvesting relatives. Schmidt rated both stings 3, but Maricopa venom is far more lethal in lab tests on mice (LD50 0.12 mg/kg against the Florida harvester ant's 0.42 mg/kg).

Read more about Maricopa Harvester Ant.

Common questions about Florida Harvester Ant

How painful is a Florida harvester ant sting?

Justin Schmidt rated it 3 on his 4-point scale and wrote: "Bold and unrelenting. Somebody is using a power drill to excavate your ingrown toenail." (The Sting of the Wild, 2016; Schmidt sting pain index). The pain lasts longer than usual for ant stings (UF/IFAS).

Are Florida harvester ants aggressive?

No. University of Florida entomologists describe it as not aggressive: it "almost has to be forced to sting someone". Even the big-headed major workers seem no more aggressive than the smaller ones (UF/IFAS).

Where do Florida harvester ants live?

From Florida to North Carolina and west into Mississippi and Louisiana, nesting in sand in open woodland and grassy areas. It is the only harvester ant east of the Mississippi River (UF/IFAS).

Why do Florida harvester ants put charcoal on their nests?

Nobody knows. Mounds are often covered with small pebbles or charcoal from burned areas, and the purpose of this decoration is poorly understood (UF/IFAS; Wikipedia).

How deep is a Florida harvester ant nest?

Mature nests are usually 2.5 to 3 m deep, with seeds stored 40 to 100 cm underground in flat granaries (Wikipedia; Tschinkel 2004).

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