Cluster Flies: A Fall Invader That Lives Up To Its Name
An annoying fall invader of homes, cluster fly adults are now on the move, looking for a warm spot to overwinter.
As the days grow shorter and the night temperatures drop, a number of insects begin looking for their winter’s lodging. These are insects that overwinter as adults. They spend the winter as adults because they need protection from cold temperatures. Other insects overwinter in the form of eggs or pupae. Those that are adults are more vulnerable and must find a suitable location where they won’t freeze. There are several that make a yearly fall appearance, including Boxelder bugs, multi-colored Asian lady beetles, western conifer seed bugs and cluster flies. The one that causes the most dismay for many people is the cluster fly, Pollinia rudis. It’s because they resemble big houseflies and are found in groups on a sunny outside wall or …
