In the heart of the Amazon rainforest, a cricket's final moments unfold in a brutal display of nature's ingenuity. As the sun sets, the cricket, unaware of its impending fate, leaps onto a shrub's stem, only to become ensnared in a deadly embrace. Over the next hour, it is dispatched, dismantled, and butchered, piece by piece, by a hidden army of ants. This is not the work of some monstrous, carnivorous plant, but a testament to the intricate dance of survival and cooperation in the natural world. This may be the most savage ambush attack we've ever heard.
The relationship between ants and plants is a fascinating one, with many examples of myrmecophily, or the intimate bond between ants and plants. Some plants offer sugar or protein 'treats' to recruit ants as security forces or seed dispersers, while others provide accommodation. But one of the most complex myrmecophilous relationships is between the shrub Hirtella physophora and the ant Allomerus decemarticulatus. This ant, barely 1.5mm long, has a superpower not of size but of numbers. Its colony, spread over the host plant in barracks or domatia, can number up to 1,200 individuals.
The plant provides food in the form of carbohydrates and extra-floral nectaries, but the ants' needs go beyond sugar. They use materials provided by the plant to build a trap. First, they cut stiff hairs known as trichomes from the plant's stems and arrange them into a complex, criss-cross scaffold. Next, they chew a fungus to create a living, adhesive paste that grows over time across the scaffold. This matrix of hair and fungus forms a platform along the length of the plant's stems, with a sheltered cavity beneath where the ants can move in relative safety.
The surface of the platform is pock-marked with hundreds of ant-sized pores, turning the entire structure into an intricate snare capable of capturing prey many times the ants' size. This is the only collectively constructed snare so far found in the ant world. The workers sit in the pores, exposing only their heads and mandibles, which are cocked and ready to snap shut on any creature that happens to walk or land on the plant. A large cricket makes a meal more than 140 times the weight of individual ants.
In a horrific but easy-to-visualize scene, the ants grab the cricket's limbs and pull backwards, while the insect struggles in the opposite direction, where more hidden jaws are waiting to grab it. The ants hold the insect down and more workers are recruited, stinging and biting until the prey is eventually overcome. While smaller insects rarely get away, larger ones, such as crickets and grasshoppers, do sometimes escape, losing a leg or two in the process.
This may appear unsuccessful, yet it still works: the cricket is put off the idea of eating the plant, and the ants gain a considerable meal. It's an extraordinary tripartite relationship. The ants get a supply of prey; the plant gets an ever-alert, highly organized security force; and the fungus gets both a place to grow and nourishment from the ants' waste. For this ant-fungus-plant symbiosis, it's a case of win, win, win.
