What is one of the major seasonal behaviors of cluster flies?

Cluster flies are known for their distinct seasonal behavior, particularly in terms of how they manage the cold months. The correct answer highlights that cluster flies overwinter in homes, which refers to the practice of seeking shelter inside buildings during colder temperatures. They typically enter homes in the fall, often congregating in attics or wall voids to avoid the harsh winter conditions.

This behavior is driven by their need to survive in a climate that is unsuitable for their activity, as adult cluster flies become inactive when temperatures drop. When spring arrives, they become active again and emerge from their hibernation sites to mate and reproduce, which is typical for many insect species that adapt their lifecycle to seasons.

In contrast, cluster flies do not migrate long distances as a typical behavior. Instead, they focus on finding local shelter. Though they may be found in larger numbers, they do not produce multiple generations within a single season like some other pest species, primarily due to their lifecycle which includes an overwintering phase. Additionally, they do not hibernate in natural structures such as leaf litter or soil like some other insects; their behavior focuses on entering human habitats for protection against winter conditions.