Many, if not all of you, are familiar with E.B. White’s famous children’s book Charlotte’s Web. In 2006, an excellent, live-action feature film was released. The story is centered around a livestock pig, Wilbur, who is destined to be slaughtered following the county fair. An intelligent spider, Charlotte, figures out how to save him, by weaving words into her web, making him famous.
As with all spiders, at the end of summer, Charlotte’s days are numbered and she leaves behind an egg sac, which Wilber rescues and takes with him back to the farm. All winter he guards the sac. With the arrival of spring, the sac begins to stir and thousands of tiny spiders begin to emerge. Wilbur is beside himself with joy. That is until the spiderlings begin to depart. Each one spins a line of silk and is lofted into the sky. “Where are you going?” questions a worried Wilbur. “Weeeeeeeeeeeee, weeeeeeeeeee. We take to the breeze, we go as we please. Goodbye,” they respond. “Wait, what’s happening?” a despairing Wilbur implores. “Where are you going? You can’t go. I have so much I wanted to tell you. And someone I wanted to tell you about . . .”
Okay, so even though the story is fictional, a box of tissue was definitely necessary to have nearby. And despite the fact that animals don’t talk and spiders don’t spin fancy adjectives into their webs, the author certainly did get some facts correct when it comes to the natural history of spiders. Especially, their dispersal methods.
Ballooning
Spiders use a technique called kiting, or ballooning to achieve their impressive movements between locations. When conditions are perfect, a spider climbs to the highest point that it can find. In a behavior known as tiptoeing, it stands with its legs raised up and its abdomen pointing toward the sky. As a light breeze begins to blow, the spider initiates a release of very fine silk from the spinnerets at the tip of its abdomen. This specialized silk, known as gossamer, forms a triangular parachute that harnesses the air and lifts the spider up and away. Many attempts at liftoff may be made before the perfect opportunity arrives, leaving gossamer threads to cover the landscape.
Once airborne, a ballooning spider is at the mercy of the wind. While some only end up but a few feet from where they began, others are swept into the jetstream and taken on amazing journeys. Weather balloons, nearly 3 miles into the upper atmosphere, have reported ballooning spiders in their samples. Sailors on ships in the middle of the ocean have also reported witnessing spider landings. Spiders have also been discovered on newly created volcanic islands. They also occupy the highest of mountaintops. Unbelievably, spiders can survive without food while dispersing for nearly a month.
Some spiders have been observed ballooning on days with no wind at all. Baffled scientists have discovered that the earth’s electric fields can provide enough force to lift the spiders off the ground. You may have felt the electricity in the air from a nearby lightning strike or felt a small shock resulting from static electricity. Spiders use tiny hairs covering their bodies known as “trichobothria” to sense electric fields. If the strength of the field is strong enough, the spider will seek out a high point, produce silken lines and balloon away.
Autumn spider dispersal
Ballooning is not something that only newly hatched spiderlings use for dispersal in the spring. Other species of spiders use it as well, at different times of the year.
Autumn spider dispersal is an event I look forward to every year. On a warm fall day, when the breeze is slight, I begin to catch the glint of gossamer floating above my pastures and I know that the ballooning event has begun. For hours on end, I walk up and down my driveway, inspecting each fencepost. On the top of each are tiptoeing spiders of many different species, their abdomens pointing skyward. I stand and watch as the gossamer appears and extends upward. If I am patient enough, the spider will suddenly launch skyward and disappear into the sun.
I love to set up my camera equipment and photograph the event. Using the time-lapse setting has resulted in some spectacular footage. Yes, I am addicted to this awe-inspiring event, which, as I write this, has not yet occurred.
Whether or not you are a fan of spiders, this is something to watch for and be amazed by. It is yet another one of Mother Nature’s spectacles that often go unnoticed. If nothing else, you may simply consider settling down with a bowl of popcorn and watching the 2006 version of Charlotte’s Web. I can’t think of a better movie to watch at this time of the year. Oh, and don’t forget the tissues!
