Experiments

Experiments

Experimentation with living things demands your attention to attitudes toward life, science and the scientific method. To contribute to an understanding of animal behavior, the leader and 4-H members must tamper with, harm and, in some cases, kill test animals. Few people object to killing insects because they are a low order of life and the well-being of humans makes it necessary to control pest insects. One should not convey an attitude of pleasure or, conversely, an attitude of disgust if the insect is harmed by the experiment. The experiment is a logical means to an end and should have moral purpose. It should be both humbling and exhilarating to unfold and understand some of the mysteries of life.

The following experiments or observations may be performed by members or conducted as demonstrations by leaders or junior leaders. Results of some experiments will depend on what kind of insect is used. Therefore, the observer must be alert for detecting and interpreting results. Remem- ber, every experiment should have a control, or unrelated units of the experiment as a reference point.

  1. Collect a large fly and remove one of its halteres. Release the fly in a closed room and observe the fly's flight control. Recapture the fly and remove the other haltere. How was the fly's flight affected each time? Are halteres important to flight? Is a fly's flight affected if its legs are removed but its halteres left on?
  2. Catch a butterfly and clip the wings together with a paper clip. Suspend the butterfly on a string attached to the paper clip and let the butterfly quiet down. Now touch the tongue of the butterfly with a small watercolor brush that has been dipped in sugar water. What happens? Next touch the front tarsus with the brush. What happens to the tongue this time? Touch the antennae and other parts of the butterfly with the brush and notice what happens to the tongue each time. How does the butterfly respond to taste? (by uncoiling its tongue)
  3. Catch several large insects of the same kind and notice how they move and the position they take when resting. With a dark colored paint or dark fingernail polish, cover one eye of one of the insects. Does this change the insect's behavior in any way? Cover the top part of each eye of another insect and notice its behavior. Try covering the bottom of each eye of another insect, and all of both eyes of another insect to see the effects.
  4. Cut the front wings from a grasshopper, June beetle or any other beetle that is a good flier. Does the absence of these parts affect the flight of these insects? If so, how?
  5. Place several crawling insects of any kind at the center of a l0-inch circle, and determine the average length of time it takes them to crawl out of the circle. Place the same insects in a jar, refrigerate them for 15 minutes, and time them again in the circle. After 15 minutes, time them again. Next warm them gently with an electric light, and time them again. What effect does temperature have on the activity of these insects?
  6. Catch a cricket of the chirping variety and keep it in a cage you can move around. Place the cage in different areas with different temperatures, and record how many chirps it makes per minute at different temperatures. Use a thermometer to determine the temperature. Make a graph of your data. Put degrees on one scale and number of chirps per minute on the other scale. At some later time when the cricket is chirping, count the number of chirps per minute and see if you can predict what the temperature is.