Tuesday, September 05, 2006

My mom loves Praying Mantises. She has plastic figures of them around the house and she is always calling me into the garden to look at baby mantis on the box wood.

Excerpt from NY Times Article, This Can't Be LOVE::

"Sexual cannibalism became a hot topic of debate among biologists in 1984. Scientists from Cornell and the University of Texas at Austin proposed that it evolved because the males of some species could get an evolutionary advantage from being eaten. Their bodies could nourish the mothers of their offspring, raising the odds that those offspring would successfully hatch and grow up to produce their own offspring, thus carrying on the father’s genes.

The late Harvard biologist Stephen Jay Gould attacked this argument, calling it a prime example of how biologists had become “overzealous about the power and range of selection by trying to attribute every significant form and behavior to its direct action.”

Dr. Gould argued that sexual cannibalism was too rare to be significant. It is possible, he said, that females eat their mates simply because they mistake them for prey.

Subsequent research refuted parts of Dr. Gould’s argument. Some sexual cannibals, including female Chinese mantises, actually eat a lot of males. “One study estimated that 63 percent of the diet of females are male mantids,” Dr. Brown said. “So they’re the main food source.”

Other scientists have demonstrated that males can increase their chances of passing on their genes if they cooperate in their own death.

Male Australian redback spiders court females for up to eight hours by plucking the strands of their web. Once a male starts to mate, he promptly somersaults onto her fangs. He continues to mate as she feeds on him. In some cases, the male crawls a short distance away, courts the female again, and then mates a second time. He flips onto her fangs, and by the end of the second mating he is dead.

Male redback spiders benefit from cannibalism, but not because they can become food for their mates. Instead, Dr. Maydianne Andrade of the University of Toronto has found that males that are cannibalized mate more than twice as long as noncannibalized males. They also father twice as many offspring with a female that mates with other males.

'We’ve replicated the results three times — ' "

I like the style this article was written in.


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