let the entire colony play dead

2023-05-11 16:50:53

The ‘playing dead’ trick is common in nature: guinea pigs and many species of rabbits pretend to have perished, as well as various types of snakes or even some sharks. Undoubtedly, the one that plays the role of deceased best is the North American opossum, which opens its mouth, sticks out its tongue, empties its intestines and secretes malodorous fluids. Now, Australian researchers add a new family to the list: ants Polyrhachis femorata, who not only simulate their death, but all the members of the colony do it at the same time. The results have just been published in the journal ‘Australian Journal of Zoology’.

Accidentally discovered while researchers were checking out pygmy possum and bat nests on Kangaroo Island (off the coast of South Australia, southwest of Adelaide), the ant colony appeared to be dead… until one moved. “The mimicry was perfect,” explains Sophie ‘Topa’ Petit, Professor of Ecology at the University of South Australia in a announcement. “When we opened the nest box, we saw all these dead ants…and then one moved a bit.”

The researchers believe the ants were ‘playing dead’ as a defensive strategy to avoid potential danger. “This type of defensive immobility is known only among a few ant species, but we are not aware of other cases where it has been observed in entire colonies.”

On closer inspection, they found that this was not entirely perfect behaviour: some individuals took longer to freeze and some did not stop their activity. “Behavioral triggers are hard to understand,” Petit notes.

The researcher points out that these anthills, which were installed in an effort to recover wildlife after the devastating forest fires of 2020, may present a great opportunity to study this curious behavior. “Polyrhachis femorata is a beautiful tree 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. The ants provide crucial ecosystem services and are a vital part of functioning ecosystems on Kangaroo Island.”

report a bug