When are boxelder bugs more common?

Boxelder bugs are more commonly found during dry summers. This is because these conditions can lead to a decrease in the availability of their natural predators and increase the aggregation of boxelder bugs as they seek shelter and food. Dry weather encourages the bugs to congregate in larger numbers around host trees, particularly the boxelder tree, which is their primary food source.

In contrast, wet summers can lead to a higher population of natural enemies such as predators and parasites that help control boxelder bug populations. Additionally, excessive moisture can lead to fungal growth that may affect the bugs adversely. Therefore, the factors associated with dry summers—such as reduced predation and a focused need for food sources—explain why boxelder bugs exhibit higher populations during these conditions.