Exercise 1 solution

Attack the bees: nosema (a disease of the adult honey bee); the mites. The article says the tracheal mite infests the trachea; varroa is blamed as a leading cause of CCD; tropilaelaps mites spread to Apis mellifera.
Attack comb and stores: wax moth larvae (they tunnel through comb with bee larvae and honey).
Cannot place from the article alone: the small hive beetle. The article only calls it a serious pest among honey bees unadapted to it, and does not say how it harms them. The exact way each mite harms the bees (other than the tracheal mite's location) is also not described.