Why is arachnophobia part of The Web?

I get how being trapped and manipulated is thematically connected to spiders and webs, but spiders are similar enough to insects that they would be part if The Corruption, the threat Anabelle gave Martin in one of the last episodes about making spiders eat away his insides and replacing him with a mass of spiders that puppeteer his body sounds especially Corruption-like yet it is something she can do as an avatar of The Web