Ant colony can 'play dead' to keep safe

A species of ants found on South Australia's Kangaroo Island can "play dead" to avoid potential danger, university researchers believe.

The behaviour was discovered accidentally by University of South Australia scientists who were checking on pygmy possum and bat nesting boxes on the island.

They noticed a colony of Polyrhachis femorata ants in one of the boxes that appeared to be dead - until one moved.

It's considered the first instance where a whole colony has been found to employ the defensive strategy.

"The mimicry was perfect," wildlife ecologist Topa Petit said.

"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."

Professor Petit said the discovery might present an opportunity to study the ants' death-feigning behaviours, which were of great interest to many behavioural ecologists.

It is believed the species was heavily impacted by the 2020 bushfires on the island, but there remains much to learn about them.

"Polyrhachis femorata is a beautiful arboreal ant that tends to be quite shy, but little else is known about its ecology or behaviour," Prof Petit said.

"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."