Ants are famous for putting themselves at risk for the wellbeing of their colony, but desert harvester ants (Veromessor pergandei) are especially heroic. New research suggests the insects charge into spiderwebs to rescue their ensnared nestmates, sometimes ripping the silk apart to free them.
Researchers first observed the fearless ants in 2015 in the Mojave and Sonoran deserts. Not only did the insects free their comrades from the sticky silk, they dismantled the entire web afterward, ripping it apart with their jaws for up to 2 hours, the team reports in The American Naturalist. The rescues weren’t without personal risk; about 6% of rescuers got stuck in the silk themselves or were captured by the spider lurking nearby.
When the scientists brought the ants back to their lab, they discovered that the insects ignored empty webs. Their valor is likely spurred by chemical distress signals put out by their web-bound siblings, the team suspects.
The findings put desert harvester ants in an exclusive club of animals that engage in “rescue behavior,” which is typically reserved for mammals like primates and dolphins. Even rarer are those that destroy traps, limited among vertebrates to two groups of chimpanzees and mountain gorillas that disassemble poachers’ snares.
The researchers think the ants’ heroic streak may have evolved because V. pergandei has to collect enough seeds for the colony to produce hundreds of new ants daily. This makes every forager’s life—and their labor—indispensable.