Insect Play Dead for an Hour to Protect Itself from Predators

Researchers at the University of Bristol observed an antlion larvae insect whose scheme is to play dead for as long as an hour and a minute to protect itself from predators.

For a long time now, scientists have observed animals faking their death, as seen on 4 Ever Green's YouTube Video below, in a desperate move to stay away from their predators. Observers say that the amount of time playing dead is kept long but unpredictable.

A Science Focus report says that this scheme creates a fatal hide-and-seek game, as the predators' grumbling stomach cannot wait for a long period of time. Their prey needs to get on and continue with their life as well.

Charles Darwin, an English-born biologist and naturalist during the 19^th century, recorded a beetle that remained completely still for 23 minutes straight.

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'Dead' for 61 Minutes

The study entitled "Hide-and-seek strategies and post-contact immobility," which the Biology Letters journal published, examined the benefits of faking death when a predator spots small groups of conspicuous prey.

To understand further what they are analyzing, Professor Nigel Franks, lead author of the study together with his team, utilized the marginal value theorem to find out how the act of an antlion would affect its hungry predator.

A similar report from the New Scientist indicates that antlions are using sands to make pitfall traps so they can catch food.

The researchers said they noticed that after dropping the 12-millimeter-long larvae into a microbalance to get their weight, the said insects froze.

Captivated by what his team saw, Franks, together with his colleagues, observed the insects' behavior repeatedly, noting that they would stay motionless on the microbalance for a few seconds to more than one hour.

Survival Mechanism

The study investigators suspected that what they observed was a last-minute or final survival mechanism for when different kinds of predatory birds such as dunnocks or Prunella modularis, unintentionally drop antlions after taking them out of their sandpits.

They demonstrated the behavior through the use of computers hoping to understand how playing dead, or what researchers termed as post-contact immobility or PCI, and explained in the Proceedings of the Royal Society B is keeping a prey animal alive.

The said models considered different predator-prey factors such as the number of pits in a patch of sand provided, their distance in-between, the time needed for the birds to tour between pits, the birds' behavioral aspects, the possibility that a bird will drop an antlion, for example, and the amount of time that the insect stays in PCI.

Furthermore, the models were informed too, through marginal value theorem, describing the best way an animal needs to feed in order to maximize its effectiveness.

The study then weighs both the costs and benefits of an animal, specifically an insect, of staying in a single spot to eat each last morsel of food that exists there, or rather, taking the time to transfer to another food-filled spot when supplies at the original location start running low.

The study findings propose that faking dead indeed can help an insect achieve survival if it stays in a patch along with many other peers.

This appears to be due to the fact that there are different targets close by that is more worthy for the bird to collect.