Wed, 06 May 2026 23:52:47 +0000

You Won’t Believe What Cluster Flies Are Hiding Behind Your Curtains – Discover Their Secret World When darkness falls, many homeowners notice strange bugs fluttering behind their curtains—tiny, clustered masses that seem almost otherworldly. These are cluster flies, a common yet often misunderstood pest that can invade homes during late summer and early fall. But what exactly are these curious insects hiding behind your window shades, and why should you care? ### What Are Cluster Flies? Cluster flies (Diptera: Pollenia) are best recognized by their grayish-black bodies, typically measuring about 8–10 mm long, with a subtle metallic sheen. Unlike common houseflies, cluster flies are slower movers and often cluster in groups, especially near sunny windows in the late summer and fall—hence their name. They’re not drawn to food like typical houseflies but are instead attracted to warmth, light, and shelter—making your cozy curtains the perfect hiding spot.