I used IXQuick to search on these three for you. Here's what I came up with.
DIIbot belongs to a company called Digital Integrity [digital-integrity.com] (The link goes to their spider info)
Aranha is the name of a Spanish language get-paid-to-surf site. I am guessing that this is their spider, but I don't know for sure.
Kenjin is an information technology product from a compnay called Autonomy. Their purpose is to help an individual bypass dependency on the commercial search engines. That sounds intriguing, but I didn't have the time to explore any further.