All these differences help us see ants as they really are: rich in diversity, earned over millions of years of evolution as they adapted to a world’s worth of habitats, ecosystems and survival strategies. Dr. Rice calls ants “the Bauhaus creations of the natural world.” Like the architectural principle that form follows function, each strange-looking adaptation represents a major commitment in creatures with “little space for extravagance” and so illustrates yet another of the multitudinous ways that there are to be an ant. “To answer the question posed by an ant’s form,” Dr. Rice writes, “is to begin to untangle the intricate relationships that scaffold our world.”
The naturalist and author Edward O. Wilson discovered this early in his scientific career, when a mentor sent him a note about a group of ants with strange, long mandibles that could spring shut like traps. (“Wilson, find out what dacetines eat,” he wrote. “What do they hunt and catch creeping around with those weird mandibles?”) A question about morphology became a clue about a food web. The ants, it turned out, were eating springtails, a kind of hexapod that can fling itself rapidly through the air to avoid predators, but not quickly enough to outrun the incredible speed of the ants’ jaws. It was a race, Dr. Wilson wrote in “Tales From the Ant World”: “each using its own explosive devices, one to capture, the other to avoid capture.” Mr. Niga’s photographs show trap-jaw ants with mandibles like scimitars or lobster claws; some can close their jaws in barely one-tenth of a millisecond, slamming shut at speeds reaching 145 miles per hour.
We also meet Cataglyphis bicolor, with its long, spidery legs — an invaluable adaptation if you live, as this ant does, in the Sahara and need speed and height to keep you cool above the blazing sand. (For Oecophylla smaragdina, or weaver ants, long legs serve a different purpose: spanning gaps in the tree canopy as they construct nests of leaves and silk.) Leaf-cutter ants look fierce, their bodies covered in spines and spikes, but all that armor is meant not for fighting but, in effect, as a gardening tool. The ants are agriculturalists, ferrying food to the fungus that they cultivate in elaborate underground chambers, and the spikes allow them to better balance their leafy loads. In the tropics, they work in such diligent numbers that you can see the ant highways that their tiny ant feet wear into forest floors.
Learning the ways of ants teaches us that their lives are very different from our own. The ants we encounter in our own lives are almost exclusively female; the males are, in Dr. Wilson’s words, “little more than flying sperm missiles” that don’t live long and are often unrecognizable as ants at all. Queens are made, not born; fertilized eggs have the potential to be queens or workers, and will develop differently based on what the youngster is fed as she grows, a diet and a future that will be dictated by the needs of the colony. Ants also have an unusually high number of odor receptors, which allow them to decode chemical trails and messages. Some species also have three simple light-detecting eyes, called ocelli, to help them fly and navigate, in addition to the standard two compound eyes.
There are many reasons to understand ants better. Whole ecosystems are built around them, and large numbers of species, from plants to beetles to birds, are “ant obligates,” meaning that they depend entirely on their relationships with ant colonies to survive. Winnow ants disperse so many herbaceous seeds in North America, Dr. Rice notes, that “removing them causes wildflower abundance to drop by 50 percent.”