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Cannibals and Weavers

Lady Killers



With branches of kung-fu based on its movements, the mantis is the epitome of elegant lethality in the insect world. Over the years I've seen more 3- to 4-inch adult European mantises (Mantis religiosa) in the fall. The imported creatures come in pale green and tan, and are easily recognized by the black bull's-eye on their upper front legs.

In spring you can buy egg cases for biocontrol in local garden supply stores. But you have to remember they are indiscriminate killers, dispatching whatever moves whether it is good or bad for us, eating honeybees and leaf chafers with equal relish. While an egg case may hatch out 500 or more juveniles, few are likely to hang around to adulthood in your berry patch, and they are cannibalistic. Like the black widow spider, the females are known to eat their mates.

There is a harsh logic: Once the male has mated, his nutritional value is the greatest thing he has left to contribute to future generations. The female does not always consume the male and researchers differ on the percentages. But they don't just eat each other after mating. Not long ago I happened on one mature female eating another. Damage to the victor's wings indicated it was not a sudden ambush but a real fight. All I got to witness was the victor cleaning up the evidence.

Tangled Webs

In the Ancient Greek story of Arachne, the protagonist, a beautiful young lady with amazing skill at weaving, challenges the goddess Athena to a contest. Athena creates a godly tapestry while Arachne weaves a panorama of the follies of the gods. In her fury at a mortal mocking the gods, Athena puts a curse on the human, shrinking and twisting her body, cursing her to weave forever. Thus was created the spider, and this is where the order's name Araneae comes from.

In a roadside greasewood (ceanothus) bush I noticed a messy spider web. Hidden within was a neat orb. I suspected it was the work of two separate spiders, perhaps one having abandoned its home or being eaten by the weaver of the other. Most interesting were the anchor points of the main support cables for the messy part. Maybe 50 strands were attached to a leaf, combining into a single cable which, when it approached the mass, unraveled and parceled out to various parts of the mess. It made a fascinating curve, resembling images from a documentary on rope making I had seen years ago.

I consulted The Field Guide to the Spiders of the California Coast and The Pacific Coast of the United States. Not a combination at all, this was the work of a member of the genus Meteperia which spins an orb, a messy, irregular web and a central shelter for itself. Browsing further, I found another web form which I had photographed some time before but never got a look at its maker. An inverted cone (I am careful to not say "funnel web" which belongs to a dangerous Australian species), it was most likely made by genus Calymmaria.

While not all spiders build impressive webs, they can all make silk and use it for various purposes, like egg sacks and shelters. Some babies spin long strands that catch the wind and carry them far away from their birthplace, a dispersal behavior called "ballooning." Some spiders that spin webs use several different formulations, making some strands especially strong, some that yield, absorbing shock like an aircraft carrier's arresting gear, and some sticky for prey adhesion.

Funny, no one makes offerings to Athena any more, but the children of Arachne and her amazing tapestries are still with us.


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