2.3: Part Two- Termite Experiment
- Students will observe the behavior of termites and draw conclusions about their behavior.
- Students will record data as to termite behavior.
- Students will analyze data and discuss a summary of their results.
- Students will recognize elements in the experimental design to include a hypothesis, variable to be tested, control, and other variables.
Background Information
Termites are small, soft-bodied, usually pale-colored insects. These are social insects with a caste system. They live in colonies on the ground or in wood. Their food consists primarily of wood or other vegetable material. The workers are reproductively sterile and lack compound eyes. They do the main work of the colony-collecting food, feeding the queen, soldiers, and young, and constructing galleries.
Many species cause considerable damage to buildings, furniture, utility posts, fence posts, and other materials. In addition, termites are important decomposers breaking down dead trees and other plant materials into nutrients useful to plants. The cellulose in the termite's food is digested by protists living in the termite's digestive tract. This association is an excellent example of symbiosis or mutualism. Termites frequently groom each other with their mouthparts, a result of the attraction of secretions that are usually available on the body.
Problem: Observe the behavior of termites and make conclusions about their behavior. Work together in groups of 3-5:
Materials: Petri dishes, Paper, various ballpoint pens, colored pencils, Termites, small soft-bristled paint brushes, and scissors.
Initial Procedure:
- Cut several pieces of paper to fit the inside of your Petri dishes by tracing the Petri dish and cutting out the circle so that it fits in the bottom of the dish.
- Draw a large figure eight on one of the papers with one of the ballpoint pens provided (go over it several times with the pen) and place the paper in the petri dish. Repeat this on a different piece of paper with a colored pencil.
- Using a paintbrush, CAREFULLY brush 3-4 termites onto the paper in each dish and observe their behavior.
- Develop a chart or table to record your data in a way that measures what you are seeing (These will be quantitative data). Example: (termite response) +, (no response) 0, (termite avoids the markings) -. There are other ways that you may want to record what you are seeing. Be sure to include a column in the chart to record any observations (This is qualitative data).
- Discuss the termites' behavior with your group. Did you notice anything unusual that may be useful for further study? After a general discussion, each group of students will discuss an experimental question involving the termites' behavior. Once your group has developed a question, discuss it with the instructor before proceeding.
- Now, suggest a hypothesis to be tested in an experiment. Write your hypothesis below.
- Develop an experiment based on your question. Test as many other pens and pencils as needed to test your hypothesis and record your data in the table that you have made. Be very thoughtful and intentional about this step. Ask yourself: ‘will using this pen test for more than one variable?’, ‘Am I changing things in the experiment that will test for things not related to my hypothesis?’, etc.
- Carry out your experiment and record your results. Draw conclusions about your observations and give a scientific explanation as to why the termites respond as they do.
- Repeat these steps with a revised hypothesis until you think you know what is going on.
DISCUSSION/QUESTIONS:
- Were any errors or other unforeseen factors that affected the experiment(s) present?
- How would you modify possible future experiments?
- Why should we conclude that the hypothesis can be either rejected or supported, rather than proven? Can you prove a hypothesis to be completely correct?
- Why does this experiment work? How might you test this?
- What purpose do termites serve in the natural world?
Now consider this:
Termites use pheromones for communication and to coordinate their behavior within their colony. Pheromones are chemical signals that termites release to communicate with each other. There are several types of pheromones that termites produce for different purposes, including
- Trail pheromones: Termites use trail pheromones to lay down a chemical trail from the colony to a food source. Other termites follow the trail and feed on the food source.
- Alarm pheromones: When a termite encounters danger, it releases an alarm pheromone to warn other termites in the colony. The alarm pheromone triggers a defensive response in the other termites.
- Aggregation pheromones: Aggregation pheromones are used by termites to gather in groups. They are produced by young termites and attract workers to their location.
- Queen pheromones: Queen pheromones are produced by the queen termite and attract workers to her location. They also suppress the development of other reproductive individuals in the colony.
By using pheromones, termites can coordinate their behavior and ensure the survival of the colony.
- Does this information change your thinking about your experiment?
- If you read this entire lab before starting the experiment, congratulations! You researched preexisting knowledge before you began experimenting with living organisms. This is a great example of why education and extensive research is so vitally important. It can change how you think about a new problem that you’ve not encountered and draw rational conclusions with far less guesswork.
If you read the information about pheromones before class, did it help you formulate a hypothesis?
If you did not read the pheromone information before lab, do you think it may have been helpful?