Bola spider

My friend Janell Cannon, a wonderful children’s book author and illustrator, sent me an email detailing her recent encounter of a bola spider in the apple tree on her property near Carlsbad, California. It was fantastic, so I asked, and received her permission to share. Janell loves to study animals, and was the friend who accompanied me to Mongolia last fall. She has several great books in print about such things as snakes, bats, hyenas, and other such desirable species. Enjoy her bola spider (Mastophora cornigera) encounter!

“The mama bola spider has three egg packets. She suspends the globe-shaped packets (one on upper right) in a stiff web network between branches, and she is hidden in the dry leaf that she secured to the underside of the branch. Never mind that the entire tree is devoid of foliage. Nobody will EVER be able to see her! (wink-wink)

Here’s a close up. Her camouflage is designed to make her look like bird shit. Her front legs are folded up top left.

Went out at night to watch her activities. Found her weaving an egg packet.

Went back in the morning and saw that her new packet was finished. It looks like a fine vase.

It is speculated that the knobs and holes in her large body are the pheromone factory with which she attracts her prey close enough to snag with the sticky bola. Moths are her favorite. The next night, caught her hunting with the bola.

I think the tiny spider at bottom right has hatched from one of the egg packets. I imagine each packet holds several spiderlings.

Haven’t yet witnessed an actual strike, but the next night saw she already had a well-bundled moth and was going for more.

The following night, on my way to check in on Mama Bola, I found a quivering, nearly-lifeless moth that had been damaged somehow. It was on the porch deck, so I think That Cat may have swatted it. I was overwhelmed with curiosity whether or not Mama Bola would accept and eat it. I touched the moth ever so gently to the bola, and its antenna instantly fused. I let go of the moth, and the line stretched and held. Mama Bola effortlessly held the line, but did nothing.

The grip this material has on the antenna is fascinating–and stunningly strong.I decided that she was not quite comfortable with this anomalous situation, so I went away for about an hour. Came back to find the offering had been rejected.

Close inspection of the gripped antenna showed no evidence of residue. Had assumed that if the bola was gluey, that the delicate antenna would be gummed up.

Am wondering by the shape of the globule, when it is holding an object, if it creates the sort of a dynamic like those funny old woven tubes that would grab one’s finger when one attempted to pull it out of the tube.

Am now curious if the grip is developed not by sheer viscosity, but by some interesting molecular tension/compression when the glob is pulled. In order to find out the consistency of the glob and to test the theory, I would have to annoy the spider by tampering with the bola.
Also am curious about the maximum weight capacity of the bola. Am imagining attaching increasingly heavy objects…

Poor Mama Bola. She has piqued the curiosity of a giant hairless primate.”

Janell added that Wikipedia has an excellent article explaining how the bola grabs the moth.


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