It is 6 am. In the soft morning light, we can barely see the monkeys. They have just exited their sleep tree and fed on some succulent Pourouma nearby.  Their soft chatter suggests that they are relaxed and unafraid.  It is time to stretch, yawn, and be groomed.

Their choice for a siesta is a little glen of low hanging branches, just a few feet off the leaf-strewn forest floor.  We observe them through an elaborate tangle of lianas; it is as rewarding as watching a movie through a disorganised sieve.

Thus, we decide to move closer.  My partner drops to his knees and begins to crawl slowly under the lianas, guided by my whispered instructions.  On no account do we want to disturb these tamarins.  When it seems like they might notice him approaching, I hiss at him to slow down.  Inch by inch, he gets closer to the animals.

A slight scuffle with some thorny bamboo hidden within the curtain of lianas attracts the attention of the nearest tamarin.  She is the dominant female in the group, and I fear that all is lost.  Remarkably, she nonchalantly turns away and continues to be groomed by a nearby male.  They are finally becoming habituated to us stalking them. We must look too silly to be of any harm.

This is our focal group of saddleback tamarins, and they have been our raison d’être for the last two months.  We are recording their parenting behaviour and have spent weeks habituating them to our presence.  When they are indifferent to us, in moments such as this, we can obtain beautiful data on their natural behaviours in the wild: alloparenting, grooming, food sharing, infant play, and the occasional bout of agonism.

As I watch them negotiate their social milieu, I feel a happy glow come over me; I live for moments such as these.

sfus grooming

An unheralded and piercing shriek rends the air.  The curtain of lianas leaps to life and disintegrates spectacularly over my partner.  The monkeys are a mere memory—they have fled the scene, no doubt certain never to take the “funny primates” for granted again.

I rush over to him, as he tries to crawl out of the lianas.

“Oh Lord, it’s a snake. He’s been bitten,” I think, feeling a panic attack coming on.  We have only been here a month, and my worst nightmares are coming true!

He emerges like some monster from the underworld.  His person is streaked with grime, leaf litter is embedded in his hair.  His face is a mask of pain.  I am certain he is dying.  (Please, let him not be dying.)

“I’ve been bitten,” he gasps, “It’s in my pants!”

Ordinarily, the idea of a snake down his trousers might have generated a slew of jokes in bad taste.

Not this time.  I was nearing that state of panic in which your mind shuts down, and your bowels move permanently out of your control.

“Take them off!”, I shriek, and he obeys (faster than ever before, I might add.)

In vain did we search for the snake among the folds of his clothing.  We very nearly came up empty-handed, because the culprit was so SMALL.  Trapped between his forefinger and thumb, wrapped in the fabric of his trousers, was a squirming, dark insect—an ant.

There is nothing ordinary about this creature; with its bulbous head, elongated mandibles and perfectly curved ovipositor-cum-stinger, it is one of the largest ants we have ever seen.

It is Paraponera clavata, the isula or—to us folks in the west—the bullet ant.

bulletant1

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It takes a moment for the identity of the creature to sink in.  I glance at my partner, and despite the throbbing pain, I can tell he is glad that it is only a bullet ant.  He might change his mind during the next few hellish hours, but at least we will not have to evacuate him to the other side of the Andes.  A small mercy in convenience, but a tragedy of pain.

The creature in question has recovered, and is now waving its forearms and antennae at us threateningly.  Its stinger is brushed with light golden hairs, a stark contrast to its black body.  Now we can actually hear the stridulations it makes with its abdomen.  I shudder.

The mosquitoes around us are fully aware that there is a semi-naked human in the vicinity.  They drunkenly attempt to hone in on his odor plume, many of them successfully.  We carefully swat the ant off his trousers with a long stick, and it disappears instantly in the leaf litter.  We make our way back to camp, our day in shambles, defeated by an insect.

***************

There are ~ 100 million cases of hymenopteran stings each year (an incidence of 0.3-3.0%), with 40-50 deaths occurring from sting-induced anaphylactic shock within the US alone (1).

Hymenopterans vary in stinger use and venom toxicity.  Bees (or apids) embed their stingers so deep that they detach with the distal ends of their abdomens when they fly off.  Wasps (or vespids), on the other hand, can sting multiple times using stingers that can exit a victim without detaching.  Formicids or ants, however, are unique—they can hold their victims with their mandibles, and sting them multiple times, rotating in a circle.  They generally don’t need to drop their stingers after the episode, and can go on to sting further.

There are 22 recognized subfamilies among ants, with 299 genera and about 14,095 described species (3).  That’s a lot of potential stings packaged in miniature parcels of pain.  Most ants, however, will leave you alone, if you leave them alone. Only a select few have truly painful stings.

The ponerine ants are the root canals of the ant world.  We know this because Justin Schmidt of the Carl Hayden Bee Research Center in Arizona, in the course of his work on hymenopterans, has been stung by an impossible number of taxa and has catalogued his reactions in vivid detail (7).

The largest ponerine ant—the 3.4 cm long Dinoponera—is a terrifying thing, but the ant with the most painful sting is Paraponera clavata (8).  In Perú it is called the isula, but the Sataré-Mawé tribe call it the tocandira.

The sting of the bullet ant, Schmidt has been quoted as saying, is a “pure, intense, brilliant pain”, although he concedes that the location of the sting and the identity of the victim have a lot to do with how painful it can be (7).

The moment in which one is stung, however, is not the most painful part of the experience.  My partner, who has since been bitten several times by bullet ants while working in the Peruvian Amazon, reports that it is the pain that comes after the sting that is truly memorable.  He says: “The pain grows and throbs.  It lasts for hours.  The area around the wound swells.”

Yikes.

What does your body undergo once stung?

Paraponera clavata produces venom that we call poneratoxin.  This 25 amino acid peptide blocks synapses in the central nervous system by affecting voltage-dependent sodium channels that normally facilitate the action of neurotransmitters (5).  According to a report on a particularly bad case from Brazil, each sting from a bullet ant can potentially “provoke systemic manifestations such as fever, trembling, cold sweating, nausea, vomiting, [enlarged lymph nodes] and cardiac arrhythmias.”  In fact, the pain itself can last for up to 24 hours.

Unless you happen to be allergic to the sting, and subsequently do not receive treatment, the bullet ant most likely will not kill you.

What happens if you are stung repeatedly?

We now move away from Schmidt’s self-experimentation, to a remote region on the border of Pará, in Brazil and Amazonas, in Perú.  Here live  ~ 10,000 members of the Sataré-Mawé tribe—Amazonian Indians that have incorporated the tocandira into a ritual of pain and triumph.

A group of respected elders first capture several ant colonies, a risky endeavour in itself, as colonies of Paraponera clavata are small (~20 ants), and will aggressively defend their nests from perceived threats (2).  The ants are then gently soaked in a concoction of herbs that do not kill them, but temporarily anaesthetise them.  Their venom remains as potent as ever.

Each drugged ant is then woven carefully into a glove, such that the stinger alone will contact the bare skin of anyone who wears it.  By the time the gloves are ready, hundreds of bullet ants are awake within them; they are also understandably, very angry.

Each man must stand with both hands inside gloves, and tolerate the anguish of hundreds of stings for at least ten minutes.  While the stings must be excruciating, it is during the subsequent hours that participants suffer the most.  Symptoms include severe vomiting and indigestion, fever, and chills (2).

Still, everybody survives.

The Sataré-Mawé do it to garner respect from their tribe and elders, and each man will undergo the ritual twenty-five times before he is recognised as a respected adult.  Schmidt’s sacrifice to science might be unrivalled, having been stung by 78 species of hymenopterans in the course of his research, spanning at least 150 instances.  Dozens of scientists suffer bullet ant stings while working in the Amazon, as must the residents of jungles across South America, both human and otherwise.  They are an inevitable experience while working in the rainforests in which they are found.

How do you identify a bullet ant?

Although most stings are accidental, with the ant disappearing before being assessed, it is still helpful to distinguish Paraponera from the rest.  At the very least, it is important to note their general characteristics so that you can take possible Paraponera seriously.  There are several genera of ants that are often confused for Paraponera, including Dinoponera and Pachycondyla.

Dinoponera gigantea is the largest ant of the Formicidae with an average length of about 3.4 cm.  It is not as aggressive as Paraponera and will retreat when disturbed at its nest.  While Paraponera do hunt terrestrially upon occasion, they are primarily arboreal ants.  Thus, a column of large black ants on the forest floor is more likely to be while a solitary forager on a vine or leaf around head height is probably Paraponera clavata.  Its stinger can be thrust out, and its exoskeleton is harder or more sclerotised than that of Paraponera.  Despite possessing a less painful sting, and less toxic venom, Dinoponera has a larger venom apparatus overall.

Pachycondyla is a genus of large ants found across the globe, from Madagascar to Perú, a few species of which are often confused with Paraponera.  They are solitary foragers, like Paraponera, but do not have as painful a sting or as potent venom.  They are never arboreal.

I spoke with Roxana Arauco, a researcher in the Entomology Department of the Museum of Natural History (San Marcos, Lima) on how to spot a bullet ant.  Her advice: If you do get a close look at a large black ant, examine the petiole.  This is the constricted region or the “waist” in the body of an ant, and can consist of one or two segments.  In Paraponera, the petiole has a spine that points toward the head of the ant, which is quite different in appearance than other ants.  Also, the head of  Paraponera clavata is wider and more rounded than that of the Pachycondyla species.  If you look closely at these images, you will also notice some differences in the shape of their bottoms, although I desist from including lurid descriptions at this time.  However, NEVER harass ants just to look at their petioles when you suspect they are bullet ants; besides being a great way to get stung, it is unnecessarily harsh on the ant.  Roxana’s advice is to try to obtain the following images for identification later: a lateral view of the whole ant’s profile (with an emphasis on the petiole), a frontal view of the head, and a view from above of the top of the ant’s body.  Then find someone like her to help you out!

Paraponera_profile
Paraponera clavata displaying a forward-facing spike on its petiole. Photo by April Nobile from AntWeb
pachycondyla_profile
Pachycondyla apicalis displaying a triangular petiole. Photo by April Nobile from AntWeb
Dinoponera gigantea profile
Dinoponera gigantea displaying a quadrangular petiole. Photo by April Nobile from AntWeb

How do you treat a bullet ant sting?

If you discover a bullet ant on yourself or someone else, the first thing to do is to evict it, without a fuss.  If you slap it, or cause it distress, it will sting you, likely multiple times.  Bullet ants are not aggressive unless provoked, and must be treated with respect.  Alex Wild, an entomologist that hosts Myrmecos, a blog on everything ant-related, has taken some wonderful images of these ants on his hands, without being stung.  I noticed a bullet ant on my lap during dinner at my field station once.  It was a memorable, but not a dangerous experience.

If you do get stung, there are a few simple steps that help ease the pain:

Randy C. Morgan, the Associate Curator of Entomology Insectarium at the Cincinnati Zoo and Botanical Garden, recommends the immersion of the wound in ice water to prevent the spread of the venom.  Ice-water is typically an unfulfilled dream in a jungle, and so some other treatments must be used in those circumstances.  Although entirely unsuited to their original purpose of treating snake-bites, I have found that venom extractors assist in dissipating pain and extracting venom from hymenopteran stings.  A coloured liquid can usually be extracted from a sting if applied soon after the event.  There is a possibility that the extractor is merely numbing the area surrounding the sting; in this case, a most acceptable result!

Finally, take the maximum dose of an antihistamine as soon as possible to prevent an allergic reaction.  Of course, it is always useful to have an Epipen on hand as well.

Remember, this might be a painful experience, but it is typically not life-threatening.  Just life-disruptive. Everybody has a different reaction to the stings, so pay attention to your body and keep on antihistamines until the inflammation and pain die down.

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After 19 months in the Peruvian Amazon, and countless chigger, bot fly and mosquito bites, I have yet to be stung by a bullet ant.  They have tried and thus far failed; no doubt, they will succeed one day.  I can then share my own sensations, as so many have before me.

Sources:

1: Diaz J.H. (2009). Recognition, Management, and Prevention of Hymenopteran Stings and Allergic Reactions in Travelers, Journal of Travel Medicine, 16 (5) 357-364. DOI:

2: Haddad Junior V., Cardoso J.L.C. & Moraes R.H.P. (2005). Description of an injury in a human caused by a false tocandira (Dinoponera gigantea, Perty, 1833) with a revision on folkloric, pharmacological and clinical aspects of the giant ants of the genera Paraponera and Dinoponera (sub-family Ponerinae), Revista do Instituto de Medicina Tropical de São Paulo, 47 (4) 235-238. DOI:

3: Hoffman D.R. (2010). Ant venoms, Current Opinion in Allergy and Clinical Immunology, 10 (4) 342-346. DOI:

4: Morgan E.D., Jungnickel H., Keegans S.J., do Nascimento R.R., Billen J., Gobin B. & Ito F. (2003). Comparative survey of abdominal gland secretions of the ant subfamily Ponerinae., Journal of chemical ecology, 29 (1) 95-114. PMID:

5: Palma, M. S. 2006. Insect Venom Peptides. In The Handbook of Biologically Active Peptides (Ed.) Kastin, A. J. pp. 409-416.

6: Szolajska E., Poznanski J., Ferber M.L., Michalik J., Gout E., Fender P., Bailly I., Dublet B. & Chroboczek J. (2004). Poneratoxin, a neurotoxin from ant venom: 
structure and expression in insect cells and construction of a bio-insecticide. European Journal of Biochemistry, 271 (11) 2127-2136. DOI:

7: Schmidt, J. O. 1990. Hymenoptera Venoms: Striving Toward the Ultimate Defense Against Vertebrates. In (Eds.) D. L. Evans and J. O. Schmidt. Insect Defenses: Adaptive Mechanisms and Strategies of Prey and Predators. Albany, New York: State University of New York Press pp: 387–419.

8: Johnson S.R., Copello J.A., Evans M.S. & Suarez A.V. (2010). A biochemical characterization of the major peptides from the venom of the giant Neotropical hunting ant Dinoponera australis, Toxicon, 55 (4) 702-710. DOI:

More on Paraponera:

Feeding ecology and how to care for Paraponera (lovingly) but safely in captivity.

Listen to Dr. Hayward Spangler talk about “hearing” ant stridulations with your teeth.  Roberta Gibson of Wildaboutants takes on ant stridulations, providing numerous examples of ants stridulating away.

The Schmidt Sting Pain Index has been widely reported on, in many rather exaggerated forms. Cecil Adams summarises the scale as such, based solely on Schmidt’s published papers:

The Schmidt Sting Pain Index is a five-point scale, as follows:

  • Sting level 0 is virtually imperceptible — the stinger doesn’t penetrate the skin.
  • A level 1 sting is the sharp prick you get from a sweat bee or a fire ant, a rating that seems surprisingly low until you realize hardly anybody gets stung by just one fire ant.
  • A typical level 2 sting is produced by the honeybee, the benchmark of sting pain.
  • But things can get much worse. For the archetypal level 3 sting you want a harvester ant (genus Pogonomyrmex), whose sting combines intensity with duration — the pain can last four to eight hours.
  • Finally, there’s a level 4 sting, which is as bad as it can get. Schmidt knows of only three critters capable of inflicting level-4 suffering: the warrior wasp (Synoeca septentrionalis), a two-and-a-half-inch-long black bug found in the tropics; the bullet ant (Paraponera clavata), also tropical; and the tarantula hawk (genus Pepsis), two inches long, which Schmidt can find in his yard in Tucson.

Alex Wild’s guide to the most common neotropical ants. A must-see for anyone planning a visit to the Amazon rainforest. You are likely to meet a lot of these ants!

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