Sunday, February 7 turned out to be a decent day to be outdoors. It got pretty mild in the afternoon, with sunny skies and a high of about 50 degrees. With that in mind, I took the camera and went to see what I could see. Near the northern shore of Walker Lake in Shohola, PA, I found that a few flying insects were about, and a few stoneflies were observed. Tiny gnat-sized insects were occasionally seen, and as I went to see if I could find some that might be perched in shoreline rocks, I spotted the spider.

The spider looked like a small fishing spider and was on a patch of icefree water near the shore. It was only half-an-inch long and was suspended by the water’s surface tension as it sat motionless. It must have detected me as I got closer; it started to walk away from the shore a foot or so. It then did something that you don’t normally associate with spider behavior. It raised its two forelegs off the water slightly, and it then started to move on its own—except that it’s legs were absolutely still. I then realized that I could feel the slightest movement of air on the back of my neck, even though no ripples were visible on the water, and that this spider was using its forelegs as a makeshift spinnaker sail to power it over the water.

It is known that spiders use tendrils of silk to catch wind and disperse (called “ballooning”), but could they be using this sailing technique to navigate long distances over water? A group of scientists from the UK did some experiments and published their findings in 2015. They took a total of 325 spiders, comprising 21 separate species, and placed them all on dishes of water. All the spiders were able to walk due to the surface tension of water, and a surprising 201 individuals exhibited sailing ability when a small amount of artificial wind was generated. It is likely that spiders could have used this technique to travel to new land masses over the sea.

By the morning of Valentine’s Day, the temperature is forecast to be down to subzero levels, and neither spiders nor open water are likely to be spotted on the area lakes for the time being. But this is worth checking out when spring arrives and insects emerge in force. In the meantime, you can read this abstract at Bio Med Central at bmcevolbiol.biomedcentral.com/articles/10.1186/s12862-015-0402-5