Tuesday, September 14, 2010

Praying Mantis

My neighbor Kim brought me a cool critter from her flower bed.  It is sweet and lovable with soulful eyes.  It does have a bad habit of snatching up its food quickly and letting an occasional wing or leg fall to the floor.  I attribute that to its customs in its native land.
Praying Mantis (also called mantids) are named for their praying posture with their arms folded, not unlike a dog sitting up and begging.  There voracious creatures are anything but devout as you can discover by getting an insect within their quick grasp.  This creature grabbed a katydid faster than I could follow the action.
Chinese Mantis (Tenodera sinensis) were first brought to this country in 1895 as a source of pest control.  They are still readily available as pets and for gardeners in the form of egg cases to raise for their garden.  They have an unfortunate habit of eating any insects, good or bad, as well as an occasional lizard, frog or even an unwary hummingbird.*
Male Mantis- Bugguide.com
How do tell the boys from the girls?  There are several ways.  The females have 6-7 abdominal segments while the males have 8.  Also, the males have four appendages off the tip of the abdomen, a pair of cerci and a pair of styli (see picture) but the females have only the one pair of cerci.
Egg Case- (Ootheca)
Mantis females lay 100-200 eggs in an egg case attached to a woody stem.  When the first instar emerge in the spring, they disperse in search of food.  Many species of mantis are cannibalistic, eating their siblings after they are born, so moving away from home is crucial in their survival. 
Female mantis may eat a male approaching for mating, so males have to be very careful.  Even if she is receptive, he isn't out of danger, as mantids are famous for their sexual cannibalism.  The females may eat the male during or after their intercourse. Is this a strategy to improve their mating success or did they simply get  "the hungries" at an inopportune time?  Why do the males allow this?  Ask a mantid.  There are several theories.
  1. The male being eaten has longer intercourse during that time and therefore more sperm to increase his chance of breeding his own young.
  2. The male sacrifices his body to provide nourishment for the young his partner will produce.
Neither seems a reasonable choice to me, but it apparently makes evolutionarily sense to the mantid.  Some research has suggested that sexual cannibalism occurs predominately in mantids in captivity.  On the other hand, another study showed that 60% of the food of a female mantid was derived from her boyfriends.
Other species such as spiders and scorpions are known to frequently eat their mates during mating.  Some spider species have developed elaborate strategies to inform the female of their intentions.  This can include elaborate dances or motions that say "I am your species and would like to mate rather than eat you."  Never knowing whether she is in the mood, some males have other strategies to avoid the tender trap, but none are foolproof.

More on praying mantis can be found in Wikipedia
* Check out this Video of a mantis catching a hummingbird.
Our Chinese Mantis, now named Ginger, is now living at the WOLF School

No comments:

Post a Comment