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Posted by Elaine on July 19, 2006 at 22:15:39:

In Reply to: Tough to be a Male posted by c2cDiver on July 19, 2006 at 20:11:25:

This paper reflects the research and thoughts of a student at the time the paper was written for a course at Bryn Mawr College. Like other materials on Serendip, it is not intended to be "authoritative" but rather to help others further develop their own explorations. Web links were active as of the time the paper was posted but are not updated.

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Biology 103
2002 First Paper
On Serendip

The Female Praying Mantis: Sexual Predator or Misunderstood
Michele Doughty

"Placing them in the same jar, the male, in alarm, endeavoured to escape. In a few minutes the female succeeded in grasping him. She first bit off his front tarsus, and consumed the tibia and femur. Next she gnawed out his left eye...it seems to be only by accident that a male ever escapes alive from the embraces of his partner" Leland Ossian Howard, Science, 1886. (7)

The praying mantis has historically been a popular subject of mythology and folklore. In France, people believed a praying mantis would point a lost child home. In Arabic and Turkish cultures, a mantis was thought to point toward Mecca. In Africa, the mantis was thought to brink good luck to whomever it landed on and even restore life to the dead. In the U.S. they were thought to blind men and kill horses. Europeans believed they were highly worshipful to god since they always seemed to be praying. In China, nothing cured bedwetting better than roasted mantis eggs. (7) The praying mantis is known for its unique look and very interesting aspects of behavior. Their bodies consist of three distinct regions: a moveable triangular head, abdomen and thorax. It is the only insect capable of moving its head from side to side like humans. Compound eyes help give them good eyesight, but it must move its head to center its vision optimally, also much like a human. Females usually have a heavier abdomen than males. Legs and wings are attached to the thorax and elongated to create a distinctive "neck". Its front legs are modified as graspers with strong spikes used for grabbing and holding prey. (2) To say the least, the mantis is a highly evolved curiosity with raptorial limbs that can regenerate when young, wings for flight, ears for hunting and evading predators, and mysterious behavior. With such highly evolved bodies for capturing and seizing prey, why are females infamous for their sexual cannibalism of males?

The mantis has an enormous appetite, eating up to sixteen crickets a day, but is not limited to just insects. They are carnivorous and cannibalistic, and only eat live prey in both nymph and adult stages. Although customarily they eat cockroach-type insects, they prefer soft-bodied insects like flies. They have been documented eating 21 species of insects, soft-shelled turtles, mice, frogs, birds, and newts. (2) Although the European mantis was introduced to the United States to eat insects that destroy farm crops, other species are known informally as "soothsayers," "devil's horses," "mule killers," and "camel crickets" since their saliva was mistakenly thought to poison farm livestock.

Because of the interesting sexual cannibalism of the species, there have been many studies on the praying mantids reproductive processes. Breeding season is during the late summer season in temperate climates. (5) The female secretes a pheromone to attract and show that she is receptive to the mate. The male then approaches her with caution. The most common courtship is when the male mantis approaches the female frontally, slowing its speed down as it nears. This has also been described as a beautiful ritual dance in which the female's final pose motions that she is ready. The second most common courtship is when the male approaches the female from behind, speeding up as it nears. He then jumps on her back, they mate, and he flies away quickly. It is most seldom that courtship occurs with the male remaining passive until approached by the female.

The actual mating response process has been described as an initial visual fixation on the female, followed by fluctuation of the antennae and a slow and deliberate approach. Abdominal flex displays with a flying leap on the back of the female are executed in order to mount her. The female lashes her antennae and there is rhythmic S-bending of the abdomen. During one experiment, mantids were observed in copulation for an average of six hours. The male flew away after mating. (6)

Although the praying mantis is known for its cannibalistic mating process in actuality it only occurs 5-31% of the time. Especially in laboratory conditions of bright lights and confinement, the female is more likely to eat the male as means of survival. "In nature, mating usually takes place under cover, so rather than leaning over the tank studying their every move, we left them alone and videotaped what happened. We were amazed at what we saw. Out of thirty matings, we didn't record one instance of cannibalism, and instead we saw an elaborate courtship display, with both sexes performing a ritual dance, stroking each other with their antennae before finally mating. It really was a lovely display". (7) There is one species, however, the Mantis religiosa, in which it is necessary that the head be removed for the mating to take effect properly. (5) Sexual cannibalism occurs most often if the female is hungry. But eating the head does causes the body to ejaculate faster. (3)

There are over 2000 species of praying mantids that display diverse shapes and sizes. They are camouflaged to blend into their environments from tropical flowers to fallen leaves. "And although they work around the same general lines- 'wait, seize, devour', behavior patterns between different species are as diverse as their body shape." (7) Some engage in sexual cannibalism more often than others. Those that do, it seems, are responsible for giving those that don't a bad reputation.

In our society that loves gory tales of sex and violence, it seems that we have focussed more on the fatal attraction aspect of the species than trying to figure out exactly why they do it. After all, being eaten also benefits the male since he serves as a kind of vitamin for his offspring so that they are strong enough to survive. And he gets to pass on his genes. The fact of the matter is that sexual cannibalism isn't that uncommon in nature. Especially in the insect world, male redback and orbweb spiders fall prey to their lovers, not to mention the infamous black widow. Have scientists focussed too much on the tales and myths of the deadly seductress? Have we misunderstood the praying mantis?

References


1)Praying Mantis

2)Praying Mantid Information

3)Sexual and Mate Selection

4)The Wondrous Praying Mantis!

5)The Praying Mantis

6) The Praying Mantis

7) You Give Love a Bad Name



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