Sunday, December 18, 2011

Heartless

All spiders make silk, but not all make webs. And of the web-builders, not all use the webs for catching prey. I've been watching Hopalong and her friend, the small yellowish spiders that came in on pine tips, to see what she does with her silk. They hide out among the pine needles during the day, then start wandering around in late evening, mostly going up one needle, down the next, back and forth, sometimes venturing out to the glass of their container. I can't see any signs of a web, just individual strands here and there. Pathways or glued traplines? I couldn't tell.

I have provided fruit flies for their meals, which get eaten, but I have not seen how they were captured. Some spiders wait until the prey gets caught in a web, then harvest it at their leisure. Some dash out at the first tug and leap on the insect before it escapes. These spiders depend on their sense of touch to identify the vibration caused by the struggles of their captives; their eyesight isn't necessarily sharp, or may not even be used.

Some build traps or funnels and catch insects and other prey that fall in; again, eyesight is not too important for this.

Hunting spiders use their eyes. They either lay in wait or wander about, leaping on prey that they have seen.

So which method does the Hopalong tribe use? They're wanderers, but they don't seem to be all that visually oriented. I have watched a fruit fly walk right in front of one, without the spider even turning to watch, as a jumping spider would.

Yesterday, I brought in a couple of fresh pine tips, hopefully carrying assorted springtails for snacks. I put them in the container quickly, then examined them through the glass. Something moved. Springtail? No; another spider, then another, very tiny. I left them where they were; the two already there seem to be getting along fine. Two more shouldn't be a problem.

Tonight, Hoppy (#1 or 2) was wandering about on the glass, crossing paths with fruit flies and a red mite, without reacting to them. The largest of the two new spiders turned a corner and met her almost face to face. Nothing happened. Then, as they passed each other, the tips of their legs touched briefly. Instantly, Hoppy wheeled and leapt on the smaller spider; the struggle was brief, and she settled down to eat.

Hopalong has Junior for supper.

The smaller spider is the same species.

So there are two questions answered; these spiders are leapers, not trappers. And they hunt by feel, not by sight.

And they have no inhibitions about eating their relatives.

And this is for Clytie: the shield that joins the legs is shaped like a heart.

2 comments:

  1. During our freezing fog days (which lasted 2 weeks!) I was intrigued by the different spider webs I would find highlighted by the frost. Some draped from branch to branch like Christmas garlands ... some hung loose ... some were round webs, some were shaped like boats. It was fascinating!

    Thank you for the heart, Susannah, it is one of the most amazing nature hearts I've ever seen!!! You can be sure this one will show up soon on Guest Heart Thursday!

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  2. I'm not going over to their house for Christmas cheer! I might end up being the appy. - Margy

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