Like something out of an animated movie, predatory ants have been seen to carry wounded companions from battled with termites – behavior that is highly unusual among insects.
Sub-Saharan Matabele ants spend their days preying on termites. Between two to four times a day, these insects form long lines of 200 to 500 soldiers and attack termite foraging sites, Gizmodo reports. The larger ants break the termite nests, while the smaller ones swarm in to kill the termites. Then the ants bring their dead prey back to their nest.
However, termites have developed ways to fight back, including using their powerful jaws to ward off the ants. Due to this, the ants can expect to have wounded comrades at the end of a battle.
During field research at the Comoe National Park in Ivory Coast, researchers from the University of Würzburg in Germany found that the Matabele ants exhibited rescuing behavior. According to the study,
We show that a unique rescue behavior in [Matabele ants], consisting of injured nestmates being carried back to the nest, reduces combat mortality. After a fight, injured ants are carried back by their nestmates; these ants have usually lost an extremity or have termites clinging to them and are able to recover within the nest.
Upon further analysis, the researchers discovered that wounded ants called for help by sending off two chemical signals, dimethyl disulfide and dimethyl trisulfide, which they secrete through their mandibles. In turn, other ants grab their distressed companions and bring them home. Ants that are injured or have missing limbs recover, then go back to attacking termites.
The study further showed that the ants that returned to the nest without help died 32% of the time, but rescued ants survived a whopping 95% of the time. This behavior means that the colony size stays large enough – a pragmatic move on the part of the ants. In short, spending time and resources on saving wounded ants is worth it, as it keeps the strength of a colony up, allowing it to survive.
The study was published in Science Advances.