We all know spider silk is sticky, and if it were not for the adhesive qualities in spider silk, spider webs would never successfully trap insects. So how do spiders avoid getting stuck within their own webs? This question has been asked many times over the years, and there is probably not an entomologist in existence that has not been asked this question at least once. As it turns out, there is a common answer to this question, but the common answer is not so accurate. Many people claim that in addition to excreting silk, spiders also excrete an oil that prevents them from getting stuck to their own silk.
This explanation sounds plausible enough, but the fact is, no known spider possesses these oil-secreting glands. The explanation that says spiders excrete an oil to avoid sticking to their webs is so old and widespread that even some spider experts are not clear on the matter. In any case, this explanation may have been a reasonable hypothesis at one time, but science has known for decades that spiders do not possess oil-secreting glands.
Actually spiders simply step around the gobs of sticky silk that they excrete from the tips of their legs. However, sometimes a spider does step into one of these sticky silk globs, but this is no big deal to the spider. In fact, when a spider accidently steps into its own sticky silk, the spider steps out just as easily as a human steps up after stepping on a piece of gum. The spider is able to detach itself from its silk easily because just a dab of silk only has one sticky droplet. On the other hand, a spider web has several sticky droplets located at all points on the web. This means that if a fly gets caught in a web, the numerous sticky droplets will immediately adhere to the fly’s body preventing the fly from escaping. If a spider were to be caught in a web, the spider would likely meet the same fate as the fly caught in a web.
Do you think that there is any type of insect that can escape the adhesive power of a spider web?