I know that the term 'bug' in computer speak came from the time of punch cards. If a real bug (spider etc) crawled into the punch cards there'd be a problem...probably a bug.
Perhaps something similar... once upon a time a pilot was flying along and a nice orange spider sat on his ASI/HSI and he found himself flying at a speed the same as where the spider sat. He probably spent many a night training his new friend to sit still and sit where he was told...until someone else invented the bug as we know it.
Nah!!!