Please remember that spiders love messy rooms, and I do not want any eight-legged guests. Also, I read online that dust makes people sneeze, which explains my allergies. In general, everyone knows that good roommates clean up after themselves!

When we make general statements about plural nouns (like spiders and good roommates) or uncountable nouns (like dust), we use the zero article.

If the roommate said "the spiders," they would be talking about a specific group of spiders already living in the room (yikes!).