Science Focus (issue 24)

Pheromone Perfumes: Beyond Advertisements 費洛蒙香水:廣告沒有告訴你的二三事 The cosmetics industry has long been promoting pheromone perfumes for their power to attract the opposite sex. They claimed that such products can enhance a person’s charm and sexual attractiveness. Therefore, some believe that pheromone perfumes can make the one you love fall for you more easily. Is this myth true or not? What Are Pheromones? With that being said, you may wonder what exactly is a “pheromone”? First discovered in insects, pheromones were defined in 1930s as hormones that are secreted outside the organism’s body (ectohormones) with effects on the conspecifics [1]. Although consensus cannot be reached on how to define pheromone beyond insects, most definitions agree that pheromones should be species-specific chemicals that have well-defined effects on the behavior or endocrine system of another individual [1]. Pheromones should also consist of one or just a few chemicals, with the effects minimally affected by learning (that is, one cannot easily learn to resist those inherent reactions) [1]. How Do “Pheromones” Work in Animals? Insects are well known to possess pheromones. Female silkworm moth (Bombyx mori) produces a pheromone called bombykol to attract males [2], initiating and guiding the flight of the male moth to the female [1]. Pheromones also play a crucial role in regulating the honey bee society. The queen releases “queen pheromones” as signals to stimulate various behaviors of the worker bees, including cleaning, building, guarding, foraging, and brood feeding, and inhibit ovary development in workers to ensure that the queen is the only fertile female in the hive [3]. Since 1960s, scientists began to investigate whether mammals also possess pheromones. They observed that vaginal secretions of rhesus monkeys seemed to elicit copulatory behaviors in males, and agents in the tarsal scent glands of male deer appeared to elicit licking by females [1]. These observations led to the discussion of whether mammalian pheromones exist. The androgen derivatives found in boar saliva are considered a typical example of mammalian pheromone by some scientists [1, 4]. Boars are known to salivate profusely and foam around the mouth when sexually aroused. It is suggested that the volatile pheromones will diffuse in the air and elicit lordosis, a posture in which the spine of a sow bents inward to prepare for mating. Some scientists doubted that these agents are pheromones. They argued that sows do exhibit mating preferences, i.e. they do not lordose for all salivating males; the chemicals isolated from saliva cannot elicit the same response in all sows [1]. Taken together, the results are By Charlton Sullivan 蘇柏安