What is an example of structural pests mentioned?

Termites are classified as structural pests because they directly damage and compromise the integrity of buildings and other wooden structures. They feed on cellulose found in wood, which can lead to significant structural damage if not controlled. When termites invade, they often go unnoticed for long periods, leading to extensive damage before any signs of their presence are evident. The identification of termites as structural pests highlights the need for effective pest management strategies to protect buildings from their destructive feeding habits.

The other options, while they can be pests, don't primarily concern structural integrity in the same way that termites do. Grasshoppers are agricultural pests that damage crops, bees are generally beneficial insects important for pollination, and flies are considered nuisance pests but not typically associated with structural damage.