A bitemark is the mark left by a bite of an animal.
Forensic Odontology
If you are asking what the company is on the computers used in the show, you can see on Freddie's laptop a pear with a bitemark in it; it is not a real company, it's a parody of the Apple Computer logo, which is an apple with a bite mark in it. iCarly features many parodized products, which are also seen on other Dan Schneider shows (Drake & Josh, Zoey 101, etc). Others on iCarly include ZapLook (Google), SplashFace (YouTube), Chickipedia (Wikipedia), Skybucks (Starbucks), Pear Phone (iPhone), etc.
Camel back crickets, also known as cave crickets, do not bite humans. Spider crickets, on the other hand, may bite if handled roughly or threatened, but their bites are not venomous or harmful to humans.