Context: At least a few insects have nociceptors, cells that detect and transmit sensations of pain. This was discovered in 2003 by studying the variation in reactions of larvae of the common fruitfly Drosophila to the touch of a heated probe and an unheated one. The larvae reacted to the touch of the heated probe with a stereotypical rolling behavior that was not exhibited when the larvae were touched by the unheated probe. Although nociception has been demonstrated in insects, there is no consensus that insects feel pain consciously

Question: How many insects have nociceptors?
Answer: a few

Question: Cells that detect and transmit pain are called what?
Answer: nociceptors

Question: When were nociceptors discovered?
Answer: 2003

Question: Nociceptors were discovered by studying the common what?
Answer: fruitfly Drosophila

Question: Which probe did the larvae react to?
Answer: the heated probe