Grades: 9-12
Essential Skills: Language Arts, Science
Duration: 1 class period
OVERVIEW
Students learn about pheromones, how honey bees use pheromones for communication, and carry out a scientific experiment to test whether humans have pheromones.
Other Materials:
Information Sheets:
Activity Sheets:
Lesson Plan
Introduction (20 minutes)
Explain to the students that honey bees communicate to one another via odors called pheromones. Review the fact that honey bees perceive pheromones with sensory apparatus on their antennae.
Discuss the ways pheromones might be used and make a list on the board. Read Information Sheet 28.
For example, honey bees use pheromones to find and recognize each other and to locate enemies during defense of the colony. Guard bees "smell" any bees entering the hive, and if the bees don't have the correct pheromone of that particular hive then they are expelled. When the new queen bee flies out on her mating flight, she produces a special odor to attract drones called a sex pheromone. Bees also use odors to help locate their hive, or their new home after swarming. To humans this pheromone smells lemony. Finally, when a bee stings, it gives off an odor that smells like bananas called an alarm pheromone. It attracts other bees to come to the defense of the hive.
AHB Notes: Africanized honey bees are sensitive to odors and may be more easily aroused than
European honey bees. For example, the odor of newly cut grass has been known to arouse bees. Stay
alert when you or others are mowing the lawn. Bees also may respond to lemony or other citrus scents. Avoid using perfumes or aftershaves, heavily scented shampoos or chewing heavily scented gum while hiking. If horseback riding, avoid using fly contro
l products on your horse that have a lemony odor.
The students will do an experiment to test whether they can determine the sex of a person by smelling an article of clothing. (Some students are amazingly accurate, particularly if their parents don't smoke and they don't have colds or allergies.)
Have the students wear their own unmarked T-shirt for 24 hours, or as long as possible. Discourage the use of perfumes, colognes or scented soaps that may give clues about the sex of the individual. Have the students bring the shirts to school in the plastic bag, and number them secretly so that only you know whether the wearer was a boy or girl. It is best not to record the identity of the wearer because it can be quite embarrassing if you know everyone has identified you as the wrong sex!
Pass the bags around and have each student smell the contents and record whether they think the T-shirt belongs to a boy or girl. Tell them to try not to think about it, but record their first impression. Check their results to see if some shirts were harder to distinguish than others and whether some students are more accurate at determining.
Note: Students tend to get overwhelmed if there are too many shirts, so ask for an equal number of volunteers of each sex to wear the shirts, perhaps three to five, for a total of six to ten shirts.
Tabulate the results for each shirt and discuss the results.
Additions
Extensions:
Explore the process of habituation by asking students to smell a test object with a distinctive odor such as a lemon. Have them record their perceptions of the lemon after smelling a sample of perfume. After smelling two different types of perfume, blindfold a student a see if he or she can distinguish a lemon from an orange. How about from an onion?
(for understanding only, not to be tested)
Bibliography:
Pheromones of Social Bees, by J. B. Free. Published by Chapman and Hall, London, 1987.
Insect Societies, by E. O. Wilson. Published by Academic Press, NY., 1971.
