Pollination
In his book, "Biology: Life on Earth," biologist Gerald Audesirk points out that seed- and pollen-producing plants are critical to life on Earth. These plants provide food, medicine, shelter and other resources for people and animals. They could not exist without insects and other small arthropods that help distribute pollen and seeds across large distances. Honeybees, wasps and butterflies are particularly well-known for their role in pollination, but spiders, moths, scorpions and numerous other arthropods aid in the process of plant reproduction.
Food
Arthropods are an important source of food for humans. Lobster and shrimp are popular delicacies, but humans also eat insects like crickets and grasshoppers. Arthropods also provide nutrition to other thousands of animal species, many of which are then eaten by humans. Many animals that play an important role in human science, research and well-being also eat arthropods. Chimpanzees, humans' closest relative and the subject of much scientific research, frequently eat ants.
Pest Control
Though some arthropods, like ants and termites, are considered pests, other arthropods control their populations. Spiders hunt insects and prevent them from overrunning the planet. The interactions of arthropods with one another form a delicate ecological balance that directly benefits people.
Medicine
Arthropods, primarily insects, have been used for thousands of years in traditional medicine. Honey is particularly popular as a wound treatment, and some modern holistic physicians advocate honey produced by honeybees as a solution to several medical ailments. Modern medical practitioners also benefit from arthropods. Horseshoe crab blood, for example, is sometimes used to test the safety of antibiotics.
Legal
Entomology is the study of insects, their behavior and their interactions with their environment. Forensic entomologists use insects at crime scenes to uncover important information. The presence or absence of certain insects can be used to determine time and location of death. It can also be used to narrow down a list of suspects, and lawyers may use the testimony of forensic entomologists to convict or exonerate people accused of crimes.