The results of a new study reveal that black fire ants use sand to draw liquid food out of containers when faced with the risk of drowning. This is the first time sophisticated tool use has been reported in ants.
A laboratory experiment has shown for the first time that a species of ant has the remarkable ability to adapt its tool use*. When provided with small containers of sugar water, black imported fire ants were able to float and feed on the surface, but when researchers reduced the surface tension, the ants started depositing sand grains on the inside of the container leading out of it.
*Tool use is seen as an indicator of cognitive sophistication and has mostly been observed in primates and some species of birds. But in invertebrates this behavior is less well studied and has previously been thought of as hard wired and inflexible.
“We found the ants used sand to build a structure that could effectively draw sugar water out of the container to then to be collected. This exceptional tool making skill not only reduced the drowning risk of ants, but also provided a larger space for them to collect sugar water.”
-Dr. Aiming Zhou, associate professor, Huazhong Agricultural University, Wuhan, China
The sand structures were found to be so efficient that they could siphon almost half of the sugar water out of the containers in five minutes. The results not only demonstrate black imported fire ants’ ability to use tools to forage but also that they can recognize an increased foraging risk and can adjust their tool use in response to this.
“We knew some ant species are able to use tools, particularly in collecting liquid food; however, we were surprised by such remarkable tool use displayed by black imported fire ants. Our findings suggest that ants and other social insects may have considerable high cognitive capabilities for unique foraging strategies.”
-Dr. Jian Chen, Research Entomologist, The U.S. Department of Agriculture’s (USDA) Agricultural Research Service (ARS), Stoneville Mississippi
Journal Reference: Aiming Zhou, Yuzhe Du, Jian Chen. Ants adjust their tool use strategy in response to foraging risk. Functional Ecology, 2020; DOI: 10.1111/1365-2435.13671