It’s a hallmark Halloween decoration: Sticky, burdensome cobwebs that stretch across ceilings and walls, remnants of spider occupations gone by. Some homes don’t need the artificial version, with real cobwebs a persistent nuisance that requires perpetual prodding with a duster. Where do these cobwebs come from?

The term cobweb is used to describe any web spun by a member of the Theridiidae family of spiders, made up of a number of species that tend to be found in residential homes. But colloquially, people tend to use the phrase to refer to abandoned threads of webbing they wind up clearing with brooms. When in use, these cobwebs tend to be sticky but unstructured, lacking the amazing and intricate design of webs woven by other species. Spiders make webs in the hopes of trapping prey, but if one location isn’t proving fruitful, they’ll move to another. That—along with the death of the web owner—can lead to abandoned cobwebs that eventually fall apart, dangling listlessly from room corners, collecting and trapping dust.

It’s that flypaper characteristic that likely results in you noticing a cobweb for the first time. As particles accumulate, the cobweb becomes more visible. You may also notice single web strands in isolation. These are likely from a spider’s interior travels as they search for a place to settle in.

If you want to reduce the cobweb clutter, regular dusting will reduce both their visibility and their existence. You can also look for and seal cracks around windows or doorways that might provide access. Maybe wait until after Halloween, though.

[h/t realtor.com]