ADELAIDE, Australia — You may have seen a crafty animal or even a person playing dead to avoid a hungry predator — but have you ever seen an entire community try this tactic? Scientists in Australia have found an entire colony of sneaky ants who all play dead to fool predators.
The species on Australia’s Kangaroo Island appeared to play dead when threatened, a behavior that University of South Australia researchers believe is a world-first. The team were originally checking pygmy-possum and bat nest boxes when they accidentally discovered a colony of Polyrhachis femorata ants that appeared to be dead, until one “messed up” and moved.
Researchers believe all of the ants were playing dead as a defensive strategy to avoid potential danger. Published in the Australian Journal of Zoology, this is the first time that a whole colony of ants has been recorded feigning death, and the first record of the Polyrhachis femorata ant species for South Australia.
Wildlife ecologist and UniSA Associate Professor S. “Topa” Petit says she was surprised by this discovery in one of the nest boxes.
“The mimicry was perfect,” Petit says in a university release. “When we opened the box, we saw all these dead ants…and then one moved slightly.”
“This sort of defensive immobility is known among only a few ant species – in individuals or specific casts – but we don’t know of other instances when it’s been observed for entire colonies,” Petit continues.
“In some of the boxes containing colonies of Polyrhachis femorata, some individuals took a while to stop moving, and others didn’t stop. The triggers for the behaviour are difficult to understand.”
Petit says that nest boxes may present an opportunity to study the ants’ death-feigning behaviors, which are of great interest to many behavioral ecologists investigating a diversity of animal species. Researchers made this discovery during the Kangaroo Island Nest Box Project, where they monitored 901 box cavities across 13 diverse properties as part of wildlife recovery efforts following the region’s devastating 2020 bushfires.
Co-researcher at the Kangaroo Island Research Station, Peter Hammond, says he used to call the Nest Box Project “Friends of the Invertebrates,” because invertebrates were often the only occupants of the bat and pygmy-possum nest boxes.
“We are learning a lot about invertebrates as well as targeted vertebrates,” Hammond says. “Most of our several hundred boxes are on burnt ground, but we also have some on unburnt properties as controls because our aim is to determine the value of nest boxes in bushfire recovery.”
“Polyrhachis femorata is strongly associated with the critically endangered Narrow-Leaf Mallee community, where it colonized several boxes very quickly. However, we also have records for two other properties further west, indicating that the ants will use other habitats,” the researchers adds. “We believe that the Polyrhachis femorata species was strongly affected by the bushfires.”
Petit notes that there is still a lot to learn about this sneaky species.
“Polyrhachis femorata is a beautiful arboreal ant that tends to be quite shy, but little else is known about its ecology or behavior,” Petit says.
“We have a relatively unknown world of ants under our feet and in the trees. Ants provide crucial ecosystem services and are a vital part of functional ecosystems on Kangaroo Island and elsewhere.”
“It is very exciting that such an endearing species as Polyrhachis femorata is living on Kangaroo Island and we look forward to finding out more about its ecology,” the study author concludes. “We have no doubt that other ants with similar death-feigning behaviors will be discovered in Australia, but it is thrilling to be among the pioneers.”
South West News Service writer Dean Murray contributed to this report.
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