There is a species of fire ants that turns sand grains into a powerful tool for food extraction. Its design is so clever, it reduces drowning risk at the same time. Not only is it an extraordinary way of gathering food, but ants are not exactly known to be tool users (unlike humans, apes, elephants, crows, and even sea otters).
Ants and Their Tool-Building Capacity
Very few invertebrates have displayed tool-building capacity. This lack of ability may indicate that insects and bugs are inflexible, rule-based creatures incapable of thinking outside the box.
However, fire ants have displayed a tool-building capacity, using grains of sand as a tool while foraging for liquid food. This species is native to South America, but they’ve become an invasive species in the southern states of America too.
The Research
Aiming Zhou, an associate professor at Huazhong Agricultural University in China, led the research, as she had a hunch that black imported fire ants could adapt their tool use when facing risks. To stimulate these risks, the researchers set up an experiment to see how the fire ants would adjust their tool use in response to an increased chance of drawing.
To do so, researchers filled several small bottle cap-like containers with sugar water (something ants can’t resist). Since they have water-resistant exoskeletons, they can easily dive right in and guzzle the sugar water while skimming the surface of the bath. However, the researchers added a non-toxic surfactant to the sugar water to reduce surface tension, taking away the ants’ aquatic advantage. This resulted in an increased occurrence of drowned ants.
The “Tool”
Researches then provided the ants with a familiar resource – sand grains. The ants proved to be clever by pilling up the sand around the containers, allowing them to siphon the sugar water from the food container. However, when the same ants were offered sugar water that was not with the surfactant, they didn’t build sand structures at all.
These findings suggest that social insects, such as ants, may have considerably high cognitive capabilities for unique foraging strategies.