Cockroaches deliver karate kicks to avoid being turned into "zombies"

/ The happy wasp administers two bites: one to paralyze the legs, the other to make the roach his zombie slave.

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If you want to see how horrible "red teeth and claws" nature is, you just have to turn to the wasp, an emerald gem. The female of the species is known for her unsuspecting pious cockroaches with a venomous villain who makes cockroach her docile slave. In this way, she will be able to lay her eggs in the roach still alive and bury her alive, thus ensuring that her offspring will eat when she leaves. Even if you do not like cockroaches, it's a horrible fate: they become undead.

But it turns out that the poor cockroach is not helpless, according to an article by Brain, Behavior and Evolution with the rather funny title, "How not to be transformed into a zombie". Cockroaches can use their hard, bristly legs like weapons, even with large kicks to ward off a cheering attacking wasp. This is the most effective way cockroaches fight attacks to turn them into insectoid zombies.

"The cockroach has a series of behaviors that it can deploy to repel the zombie manufacturers."

The author, Vanderbilt University, has the gift of creatively studying the aggressive behavior of various creatures; his specialty is the predator / prey interaction. In 2016, the naturalist and explorer Alexander von Humboldt reported, in the nineteenth century, the electrical eel in Venezuela that leaped aggressively and dazzled horses through a series of high voltage discharges. (Part of this experiment involved LED lamps mounted on an alligator head, attached using conductive tape, to better visualize these discharges. case.)

This time, he studied the defense mechanisms of the American cockroach (Periplaneta americana) against female wasps (Ampulex compressa, also called Emerald Cockroach Wasp). Catania had read stories of cockroaches that were trying to defend themselves against these devastating attacks and thought that they deserved to be examined more closely – in this case, with videography at very low speed, it was better to better understand the complexity of interactions.

• A cockroach will adopt a position on stilts to escape the attack of the happy wasp.
• The cockroach sets up a kick against an approaching wasp.
• The cockroach swings his leg like a baseball bat to sweep the wasp.

The wasp delivers two stings. The first paralyzes the legs of the roach. Then the wasp sticks its sting into the soft tissues of the throat and into the brain. All this takes only 11 seconds. This allows the wasp to drive the cockroach now docile to its nest by the antenna – once the cockroach engages in compulsive grooming behavior, because who does not want to have the best possible look while being eaten alive? But a cockroach has a decent chance of surviving if he can spot the looming attack in time.

"The cockroach has a series of behaviors that it can deploy to repel the zombie makers." "It starts with what I call the guard position, as in fencing." It is also called "stilts". From this position, the roach can follow a wasp that approaches and raise his body as best as possible. kick fast and hard at the wasp's head and body. The cockroach uses his leg almost like a baseball bat. If that's enough, "the wasp usually thinks it's a smaller, less defensive cockroach to have," he says.

"The best strategy is to be vigilant, to protect your throat and to hit the attacker's head over and over."

He found that the anti-kick defense was surprisingly effective: 63% of adult cockroaches caught the approaching wasp and resisted the attack for three full minutes (Catania success criterion). Young people, alas, have not been so lucky. Almost all cockroaches in the experiments failed in their defense and were turned into zombie slaves.

Catania hopes her work will help reveal how these unique predator (wasp) and prey (roach) behaviors have evolved over time. "It seems likely that cockroach tusks evolved in response to a wide range of predators," he writes. "In contrast, each wasp jewel is" a born cockroach ", the result of a successful attack of a cockroach."

So, what is his advice not to be turned into a zombie, at least if you're a cockroach? "The best strategy is to be vigilant, protect your throat and hit the attacker's head over and over again," he writes. It could work for humans as well.

Video provided by Ken Catania / Vanderbilt University.

DOI: Brain, Behavior and Evolution, 2018. ()