of walls while the weather is cool. Once the home's heating system becomes active for the season, the insects may falsely perceive it to be springtime and enter inhabited parts of the home in search of food and water. Once inside inhabited areas of a home, their excreta may stain upholstery, carpets, drapes, and they may feed on certain types of house plants. In the spring, the bugs leave their winter hibernation locations to feed and lay eggs on maple or ash trees. Clustered masses of boxelder bugs may be seen again at this time, and depending on the temperature, throughout the summer. Their outdoor congregation habits and indoor excreta deposits are perceived as a nuisance by many people, therefore boxelder bugs are often considered pests. However, boxelder bugs are harmless to people and pets. The removal of boxelder trees and maple trees can help control boxelder bug populations. Spiders are minor predators, but because of the boxelder bug's chemical defenses few birds or other animals will eat them. Boxelder bug populations are not affected by any major diseases or parasites. References External links Box Elder Bug – large format photos and information Serinethinae Household pest insects Hemiptera of North America Insects described in 1825 Taxa named by Thomas Say