First, the material for the bridge thread emerges from one of the spider’s specialized silk glands and is formed into a strand by its spinnerets. The loose end is drawn out by gravity or the breeze and allowed to blow in the prevailing wind, a process called kiting or ballooning.

If the strand does not make contact with something and attach to it, the spider may gobble up the strand and recycle its proteins, then try again. If the gap is bridged, the spider reinforces the strand and uses it to start the web.

A single bridge thread may be left in place overnight to mark a spider’s territory and a desirable starting spot for building a web the next day. C. CLAIBORNE RAY