Using a microscope allows us to see things we cannot easily observe with the naked eye. This makes many objects fascinating to study, and the world of insects and arachnids is no exception. This article explores what a spider looks like under a microscope, and it includes tips for conducting this simple experiment.
A spider’s legs are one of the most interesting features to view under a microscope. They look long and thin, with many individual hairs. At higher magnification, the legs are clearer and students can easily observe the tendons that allow for movement of the legs. The legs also contain a number of organs that help the spider move and sense its environment. For example, there is a small spherical pit located at the end of the leg called the tarsal organ that is believed to detect odors and humidity.
The legs of a spider are also lined with tiny sensory hairs that can be seen under the microscope. These so-called slit sensilla and lyriform sensilla enable the spider to sense its movements and vibrations on surfaces it crawls on. Each hair consists of a number of flattened fibers that push against the surface and create friction. Having more points pushing against the surface increases the adhesion force and improves the ability of the leg to climb and grip surfaces.
To observe a spider under the microscope, first find a complete, dry spider web and carefully remove it. Place the web on a slide and cover with a cover slip. Paint a small area of the slide with clear nail polish, not too much—just enough to keep a web attached to the slide. Students can then use a microscope to make observations of the spider web, including observing the silk strands.