Some people are under the silly impression that a spider can hold its breath in order to avoid inhaling toxic fumes from your can of Raid. The relationship between insects and insecticides is not comparable to humans and mustard gas. For example, most household bug-sprays work by killing the bugs on contact, and not by hijacking their respiratory systems.
Although many spiders have a respiratory system, neither spiders nor insects breathe in the same way as humans, so obviously spiders cannot hold their breaths. Arthropod respiration works by enabling a process called “passive diffusion,” and this does not allow them to consciously hold their breaths until you are done spraying your raid all over your apartment.
The reason why home bug-sprays don’t always work has more to do with the fact that the majority of store-bought bug sprays are designed to kill insects and not spiders. However, spiders will die from bug-spray exposure eventually, but not right away like insects. This has led many to assume that the spiders are all surviving because they know how to hold their breaths. So if you were one of those people who believed this, you know better now.
Have you ever failed to kill a spider after spraying it several times with bug-spray?