Sandsquiggles's Blog

Yesterday I woke around 7:00 a.m. to a dense fog hiding the bay. The fir trees along the edge of the cliff were spookily visible. The fog intensified during breakfast. But by my last cup of tea, the sun began sneaking through. The firs again began to appear, as did the bay waters and the far shoreline. Looking toward the sky, the blue deepened with every passing minute.

Scanning the scene created by the beginnings of a beautiful day on the west side of Little Kennebec Bay, I notice spider webs in and between the tops of the balsam firs that grow above the cottage’s shoreline. In the light southerly sea breeze, these nets were sparkling and glittering against the deep azure sky.

For a few minutes after the fog burned off, condensation coated these webs. The droplets of moisture rendered the beauty and intricacy of several orb spiders’ fantastic spiral nets.

I wondered how an orb spider weaves such an artistic trap forty feet above the ground and sometimes one suspended between the tops of two trees four to six feet apart. And, if all conditions are proper, they can construct them in an hour or less and usually take them down the next day.

Web suspended between two trees. Primary cable visible on left, as is the left branch of perpendicular Y-cable.

All spiders have one to four pairs of spinnerets—the number depends on the species—projecting from the end of their abdomen. Spinnerets produce the threads or silk that forms the web. Each spinneret ejects a filament thinner than a hair that combines with others to form the silk of the individual cables of a web.

To construct a web between the tops of trees, a breeze is required. Initially an orb spider climbs to a secure branch, a high point, and releases a long, sticky thread. Wind catches the thread and carries it across the open space to another branch where the thread sticks and becomes anchored. The spider then tightropes across this initial cable (the primary or horizontal cable) to the far end, emitting silk along the way strengthening the cable. Then the weaver returns to the middle and drops down to a third anchorage point directly below the primary cable. As it falls, it pulls a portion of the primary cable with it to a taut point, then releases more silk as it continues to fall to a third anchorage point. This forms a Y-shaped perpendicular support cable. From this point the spider climbs back to the original anchorage point and begins to produce the web’s radial cables. Once these are complete, the spider begins spinning the spiral cable between the radials. When it reaches the center point of the spiral, the orb weaver strengthens it and sits, then waits for its prey.

Amazing! Orb spiders make high-wire preforming a matter of routine.

ʃ ʃ ʃ ʃ

© Copyright by Richard Modlin August, 2014