Grass Spider

 

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I’ve visited the web of this female Grass Spider three times during September 2014, and it has been interesting to learn about her behavior. The web faces east and is woven into the grass on the bank of Loch Raven Reservoir, Maryland; she has a spectacular view of the water, but she can’t enjoy it because Grass Spiders don’t see images as we do, but only sense different levels of light.

Grass Spiders are funnel weavers, meaning that they lay funnel shaped webs on the ground, or higher up in thickets of vegetation, and spend most of their time concealed in the stem portion of the web, waiting to ambush prey.

On my first visit, I took a small pinch of sand and slowly dropped a few grains into her web, trying to mimic the vibrations caused by a trapped insect. It worked, she came rushing out to investigate the disturbance, and when she determined there was no prey in the web, she went back to her hiding spot. It was enough to get a couple of photographs of her, but I wanted to see a little more.

The next time I visited I brought her a black ant, readied my camera, and tossed it in the web. She came out of her lair so fast that I bungled photographing the initial part of the attack. She spent a couple of quick seconds maneuvering above the ant, and I later observed a line of silk running vertically from one of the ant’s legs to the spot in the web where she first went. So her first move must have been to secure the ant to the web. I’ll admit to having camera trouble during those first two seconds, so it is possible that she could have delivered a first bite to the ant before she threw the silk line on its leg.

After I gained focus on her, she was preparing to strike and I caught an excellent shot of her milliseconds before hitting the ant, and a blurry shot of the actual strike. She took up a position between the ant and the stem of her funnel, and would intermittently strike the ant and back off. After it was paralyzed, she cut the vertical line loose and carried the ant back to her hiding spot.

I brought her another ant on my most recent visit, but it was a very sunny day, and I was careless with my shadow, allowing it to fall over her. It spooked her, and she abandoned the ant in mid attack, retreating to her hiding spot. I moved back a little and she still would not come out to fetch the ant. I moved further back, and she finally came out to finish the ant off. I decided not to try to photograph her as she seem capable of detecting my presence in the bright sunlight. On my previous visit she seemed oblivious to my presence, and I was very close to her with my camera.

I plan on going back to visit her, but I’ll bring her some other type of insect, as my friends at http://forums.spiders.us/ tell me that spiders don’t particularly like ants, as they use formic acid as a defensive mechanism.

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