| Paraponera | |
|---|---|
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Insecta |
| Order: | Hymenoptera |
| Family: | Formicidae |
| Subfamily: | Paraponerinae |
| Genus: | Paraponera F. Smith, 1858 |
| Species: | P. clavata |
| Binomial name | |
| Paraponera clavata (Fabricius, 1775) |
|
Paraponera is a genus of ant consisting of a single species, commonly known as the lesser giant hunting ant,[1] conga ant, or bullet ant (Paraponera clavata), named on account of its powerful and potent sting, which is said to be as painful as being shot with a bullet.[2] It inhabits humid lowland rainforests from Nicaragua south to Paraguay. The bullet ant is called "Hormiga Veinticuatro" or "24 (hour) ant" by the locals, referring to the 24 hours of pain that follow being stung.[3]
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Workers are 18–30 mm long[4] and resemble stout, reddish-black, wingless wasps. Paraponera is predaceous and like all primitive poneromorphs, does not display polymorphism in the worker caste. The queen is not much larger than the workers. [5]
The pain caused by this insect's sting is purported to be greater than that of any other Hymenopteran, and is ranked as the most painful according to the Schmidt Sting Pain Index, given a "4+" rating, above the tarantula hawk wasp. It is described as causing "waves of burning, throbbing, all-consuming pain that continues unabated for up to 24 hours". It is thought that the ant has evolved this way to ward off any predators who would normally unearth them.[3] A paralyzing neurotoxic peptide isolated from the venom is poneratoxin. It affects voltage-dependent sodium ion channels and blocks the synaptic transmission in the insect central nervous system. It is being investigated for possible medical applications.[6][7]
The Satere-Mawe people of Brazil use intentional bullet ant stings as part of their initiation rites to become a warrior.[8] The ants are first rendered unconscious by submerging them in a natural sedative and then hundreds of them are woven into a glove made out of leaves (which resembles a large oven mitt), stinger facing inward. When the ants regain consciousness, a boy slips the glove onto his hand. The goal of this initiation rite is to keep the glove on for a full ten minutes. When finished, the boy's hand and part of his arm are temporarily paralyzed because of the ant venom, and he may shake uncontrollably for days. The only "protection" provided is a coating of charcoal on the hands, supposedly to confuse the ants and inhibit their stinging. To fully complete the initiation, however, the boys must go through the ordeal a total of 20 times over the course of several months or even years.[9]
Colonies consist of several hundred individuals and are usually situated at the bases of trees. Workers forage arboreally in the area directly above the nest for small arthropods and nectar, often as far as the upper canopy; little foraging occurs on the forest floor. Nectar, carried between the mandibles is the most common food that is taken back to the nest by foragers. Two studies in Costa Rica and on Barro Colorado Island (BCI), Panama, found that there are approximately four bullet ant nests per hectare of forest. On BCI the nests were found under 70 species of tree, 6 species of shrub, 2 species of liana and 1 species of palm. Nests were most common beneath the canopies of Faramea occidentalis and Trichilia tuberculata but these trees are also the most abundant in the forest. Nests were present more frequently than would be expected based on the abundance of the trees under Alseis blackiana, Tabernaemontana arborea, Virola sebifera, Guaria guidonia and Oecocarpus mapoura. The large number of nest plants suggests that there is little active selection of nest sites by bullet ants. Small shrubs however are under utilised, probably because they do not provide access to the forest canopy. The study on BCI concluded that trees with buttresses and extrafloral nectaries may be selected for by bullet ants.[10]
The small (1.5–2 mm long) phorid fly, Apocephalus paraponerae, is a parasite of injured workers of P. clavata, of which there is a constant supply because there are frequent aggressive encounters between neighbouring colonies resulting in maimed workers. They are able to parasitise healthy ants if they are artificially restrained, but this is thought to be rare in practice as healthy ants are agile and able to repel the flies. Both male and female flies are attracted by the scent of injured ants, the females to lay eggs as well as feed and the males to feed and possibly to mate with the females. The flies are attracted to a crushed ant within two to three minutes and ten or more flies may be attracted to each ant. Each ant can harbour 20 fly larvae. Carl Rettenmeyer observed P. clavata actively trying to attack A. paraponerae when they approached the entrance to their nest, but other authors have not observed similar behaviour.[4][11]