This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
This 2007 photograph of a fire ant brandishing her stinger is among the most heavily circulated images from my collection. Since several people have asked how I managed to coax the animal into such a dramatic pose, I bring you the following recipe.
But first, a digression into fire ant biology.
Everyone knows fire ants sting. But a lesser-known fact is that fire ants reserve that option mostly for vertebrate foes. When faced with a smaller threat like other ants, fire ants do something counter-intuitive. Instead of stabbing their stingers deep into enemy flesh, as one might expect a self-respecting fire ant to do, fire ants avoid stinging altogether.
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When provoked by other ants, fire ants exude a droplet of venom and wave their stinger high in the air. This behavior is called "gaster flagging", and the volatile venom serves as a deterrent to their enemies and helps recruit nestmates to battle. When pressed, a fire ant may use her stinger, but as a brush rather than a dagger. Ant armor is so tough that stingers just bounce off, they aren't terribly useful. Thus, fire ants don't stab ant opponents, they smear them.
If you'd like a photo of a gaster-flagging fire ant, one of the easiest methods is to pit two ant colonies against each other.
Ingredients
1 fragment of a large colony of fire ants kept in a small tube or vial, with larvae.
1 colony of an aggressive non-fire ant species; other pests like Argentine ants are ideal
1 large, open box at least 2 feet in the longest direction
10-20 sheets of white printer paper
1 large, flat pan filled with water
1 moderately large rock
1 flashlight or desk lamp
1-2 strobes on stands with remote triggering
1 dSLR with lens capable of 3-4x magnification
Tape the white paper to the inside of the box until every surface is covered. Place the box on a table and hang a few more sheets to cover most of the top.
The box is your studio. Place your strobe(s) inside the box facing upward, set manually to 1/4 power. When the strobes fire, the box should fill with diffuse white light. Not only does the box produce lovely light, it solves one of the big challenges of photographing fire ants. Fire ant skin, it turns out, is among the most shiny of all ants, nearly like glass, and unless the lighting is carefully managed, the ants look terrible in photographs, all glare and shadow. Place the flashlight inside the box, or the desk lamp just outside, to serve as a working light so you can see what you are doing.
Place the pan with water in the bottom of the box, and the place the large rock in the pan. The pan is a moat to keep you free of fire ants while you work. Take a few photographs of the rock at high magnification, varying the camera and flash settings, until the exposure is correct. This experimentation step is important, as you don't want to be messing around when your box fills with angry stinging ants.
Put the tube with the fire ant colony fragment on the rock and open the entrance. Once the ants are out exploring, dump the competitor ants out on the rock in large numbers. At least some of the fire ants should begin gaster-flagging. When they do, choose one ant to focus on and follow her around. For the most dramatic angles, lower yourself so that you are shooting at the ants' level.
Once you have a series of images, chose the best ones and post-process to taste.
Warning: fire ants sting, and some people experience a dangerous allergic reaction. If you don't know how you react to fire ant stings, you should probably forego this project.