As noted in the American College of Gastroenterology Case Reports Journal:
"Bug ingestions are rarely reported but can occur even during sleep. The patient's colonoscopy preparation was 1 gallon of polyethylene glycol the evening before colonoscopy, and the colonoscopy examination was otherwise normal. His colonoscopy preparation may have helped the bug escape from digestive enzymes in the stomach and upper small intestine."
Apparently cockroaches are seen in the colon much more often than ladybugs.