How arthropods eat and move.

some arthropods such as the trapdoor spider dig underground so they can get the jump on things.

Here are some of the most useful trapdoor spider facts such as trapdoor diet, habitat, reproduction, and physical characteristics. Trapdoor spider is the medium-sized spiders that belong to the family of Ctenizidae. These spiders are known for constructing burrows that are fairly ajar in order to ambush passing-by insects. The burrows are normally constructed with vegetation, soil, and a silk. However, there are certain species that do not build burrows instead they rely on silken tube with trapdoor in bark crevices. There are around 120 recognized species of trapdoor spiders. Trapdoors are associated with the funnel-web spiders and tarantulas. These spiders have shared characteristics and features such as fangs that move up and down instead of moving side by side. Trapdoor spiders are common all throughout the range of Asia, Australasia, Americas, Europe, and southern Africa. There are around 15 species across United States in which southern and western states hosts most of the spiders. taken from http://animalstime.com/trapdoor-spider-facts-trapoor-spider-habitat-diet