Spider (approx 1 inch size including the legs)

When i accidentally broke its web, this spider did something quite surprising to me: It gathered the broken remnents of its entire web, forming a tight ball with it (visible in this photo), and took that ball to its cache (not sure what it did with the web ball after that). After the operation, there was no trace that a web had ever been there. Any idea why they do that?

If you know, please post a comment or email me!