Spring is here and in full bloom! Birds are singing, new life is emerging, and spiders are… flying? Perhaps you’ve noticed them. They look like an unexpected glimmer in the air, or a lawn that appears to be covered in tinsel, or the sudden buildup of webs on the sides of a building.
Although silk is seemingly everywhere, the spiders that left them behind are not always as visible. Which begs the question; how do we stop them from coming inside?
Can Spiders Really Fly?
Spiders don’t fly in the same way that birds, bees, or even airplanes do. Instead, they use a technique known as “ballooning.” It begins when a spider climbs to the top of a leaf or branch or similar structure.
There, the spider drops a line of silk for an anchor and raises its front legs into the air. Special hairs on their legs provide the spider with information about wind speed, wind direction, humidity, and electrical activity.
Most ballooning happens when the wind blows at less than seven miles per hour. If weather conditions are suitable, the spider puts down its legs, raises its abdomen as high as it can, and releases strands of silk into the air. When it’s ready, the spider pulls the anchor line and takes flight. To change their speed or direction, they change the position of their legs.
Much like a hot air balloon, there is only so much the spider can do to keep from being blown off course. Scientists used to think that air currents alone controlled spider ballooning.
However, in 2018, Erica Morley demonstrated that sometimes ballooning occurs when there is no air movement at all. Morley conducted a study that showed when spiders are placed in a sealed box and exposed to a small electrical current, they can fly inside the box.
This happens because silk has a slightly negative charge, while the atmosphere is positively charged. The negative charge of silk both prevents strands from tangling together and allows for easier liftoff.
Oh, The Places They’ll Go
Spiders balloon for a number of reasons, including habitat disruption or to escape being cannibalized from their siblings. While most spiders balloon for short distances, they’ve also been known to fly for thousands of miles. This fact, in combination with modern travel, can make it difficult to impossible to determine how invasive species get introduced to new places.
For example, the Australian house spider (Badumna longinqua), now lives in some intertidal regions of Washington, Oregon, and California. They may have come over on ships, but it’s also possible that they flew across the ocean.
In 1832, Darwin was famously aboard the H.M.S. Beagle. In one of his journals he wrote that it sounded as though rain was hitting the sail on the otherwise clear day. It turned out that the sound was made by hundreds of spiders colliding with the sail.
This ability to disperse makes spiders vital colonizers of new environments. There are remarkably few places that spiders can’t access or can’t survive within.
Not only can spiders travel outwards, but they can also travel upwards. In 1939, a study was published by P.A. Glick titled “The Distribution of Insects, Spiders, and Mites in the Air.” Over the 5 year study, Glick and his research team found some typical results, but other were less self-evident.
For example, it was a spider that took the prize for highest recorded altitude. It was captured at 15000 feet in the air, a full thousand feet above any other collected specimen. When Glick’s study was complete and the numbers were tallied, they found that one in every seventeen airborne arthropods they caught was a spider.
How Can We Help?
Most spiders only live for about a year. In the spring, there are the highest number of spiders there will be all year and the largest percentage that are capable of ballooning.
Late spring and early summer are great times for dewebbing, because soon spiders will be too large to fly. Contrary to viral articles that flooded the internet last spring, giant spiders are incapable of flight.
The larger the spider, the less likely it is to be airborne. We can help clean up the mess that young, emerging spiders make and prevent them from establishing a home in or around your business.
Now is also a great time to schedule inspections for potential entry points. Spiders and other arthropods are at their smallest and they’re looking for a place to spend their lives.
We can help identify places that they may be entering your building, and we can help with the exclusion work needed to keep them out.
In addition, we can also put a monitoring system in place that lets us know whether arthropods are active inside.
Finally, perimeter treatments can be a supplemental service that help to reduce spiders and other seasonal arthropod pests.