Have you ever wondered what would happen if you blindfolded a spider? Well, a team of presumably very bored entomologists at the University of Nebraska have managed to do just that. However, and to the scientists’ credit, the spider that they managed to somehow blindfold is not just any spider. The spider in question possesses the largest eyes known to science. This spider has been named Deinopis Spinosa and is found in Australia, Africa, and the Americas.
This spider hunts prey at night, which could be why this spider has evolved a pair of abnormally large eyes, which, combined, equal eight eyes in total. A very dedicated biologist was not content with this theory and decided to camp out in the spider’s habitat for a total of eight months to see how it would behave after he blindfolded it with dental silicone.
It turns out that these blindfolded spiders could not catch ground dwelling prey as easily as they could with the use of their eyes, but their ability to catch flying prey remained largely unaffected. This is likely due to the spiders preferred taste for ground dwelling insects, as they tend to be more nutritious. Why do I get the idea that this entomologist just really loves camping?
Can you think of an insect that wouldn’t be negatively affected by being blindfolded? How would they adapt to survive without sight?
Scientists at Oregon State University wanted to find out exactly how spiders sense the vibration in the webs when insects land on them and how they detect where that insect has landed. To do this they built a web out of two different kinds of rope, just as spiders use two different kinds of silk, and placed on in an octagonal frame, to which a speaker was strapped to deliver different vibrations. They then placed an artificial spider in the center that has flexible legs to show how a real spider would detect the vibrations. They thought that they would find that by shaking one of the radial lines the spider would feel that lines more than the others and thus attack in that direction. However, they discovered that it is much more complex than that.
They found that different frequencies caused complex vibration patterns affecting many strands of the web. Different frequencies also caused certain strands to stay completely still. The researchers hypothesized that these different frequencies might reflect different insects landing on the web. This means that spiders can’t simply rely on one strand vibrating to lead them to their prey. They must understand how different frequencies affect the web structure in order to know which direction to attack. It turns out that spiders might just be a bit more sophisticated in their hunting techniques than we previously thought.
How do you think spiders learn to understand the different frequencies made by their webs? Is it a case of trial and error or are they taught this?