The female praying mantis has long been considered the femme fatale of the insect world.
When an ardent male approaches, according to scientific literature going back to the 18th century, the willing female bites off his head. This triggers a series of automatic copulatory behaviors in the male. Once the decapitated suitor has served his purpose, the female settles down to complete her cannibalistic feast.
At least that's what the science books say.
W. Jackson Davis says it isn't so.
He has completed a study of mantis mating behavior that reveals that these large, carnivorous insects have a complex courtship ritual that not only leaves the male very much alive but that is, Davis said in an interview, "just a lovely thing to see."
Davis is a neurophysiologist at the University of California, Santa Cruz, who spends most of his time investigating the link between an animal's nervous system and its behavior. He wanted to measure the relative strengths of the instinctive behavior involved in feeding and mating. The mantis, given its reputation, seemed a good animal to study.
Thirty pairs of males and females were placed in laboratory cages and nature was allowed to take its course in front of video cameras. Frame-by-frame analysis revealed that not once did the female try to bite the male.
"It just doesn't happen, as far as we've been able to tell," Davis said, alluding to his collaborator, Eckehard Liske, a zoologist at West Germany's Max Planck Institute. "What does happen is a rather elaborate courtship ritual in which it looks as if the female actually goes into a nonpredatory position."
Davis said that, in a few instances, the female even stroked the forelegs of her suitor for several minutes before he attempted to mate. "If these guys were human," Davis said, "you'd have to call it foreplay."
Mantis courtship rituals usually begin as the male walks slowly toward the female. Sometimes the female approaches the male. As the distance closes, the male begins swinging his antennae forward and back. Then he repeatedly curls his abdomen up and over his back. After several minutes of this, the male suddenly makes a flying leap and lands atop the female.
"What's really interesting," Davis said, "is that at about this point the female extends her forelegs straight out. She goes into a position from which she can't grab him."
The familiar "praying" position of the front legs, Davis said, is the only one from which a mantis can catch and hold prey. This is why some mantis fanciers say the usual term "praying" should be spelled "preying."
With the legs held straight out, the insect cannot do either. In some cases the female extended her legs before the male started his flying leap. In other cases she did so as he was in the air. Most often she waited until the male had landed on her back.
Davis said he has searched the scientific literature for documentation of the female mantis's anti-male reputation but found only anecdotal references to a preexisting belief.
He did find an 1886 report in which a scientist had kept a female in a jar and then put a male in with her. Nothing happened right away but the next morning he found the male headless, lifelessly hanging on to the female's back.
"I'm not going to say it never happens," Davis said, "because we know that a starved female will eat a male." Davis produced such a situation in his lab by withholding food from a female for several days and then putting a male into her cage. The male performed none of the courtship rituals and was attacked and eaten.