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Using Artwork to Gain Behavioral Insight
During this activity, students will use house fly larvae (i.e., maggots) to answer morphological and behavioral questions, all while creating unique artwork! Students will create and test hypotheses, as well as learn about the complete metamorphosis life cycle. This hands-on learning activity shows students how fun scientific inquiry can be. The activity takes 30 to 40 minutes and is designed for 20 students, although the number of materials can be easily adjusted for larger or smaller groups.
Correlation to the Next Generation Science Standards* (NGSS)
This activity address the following dimensions of the Next Generation Science Standards:
4-LS1-1. Construct an argument that plants and animals have internal and external structures that function to support survival, growth, behavior, and reproduction.
Students’ performance objectives are to:
Handle living organisms that are examples of the complete metamorphosis life cycle
Formulate hypotheses about various aspects of maggot behavior
Describe maggot behavior
Interpret observations to answer morphological and behavioral questions, as well as develop new questions
Create art while learning about insect behavior
Familiarity handling live insects
Familiarity with insect life cycles
Preparation: 10 minutes
Activity: 30 to 40 minutes
Perform this activity in accordance with established laboratory safety practices, including appropriate personal protective equipment (PPE) such as gloves and lab coats or aprons. Ensure that students understand and adhere to these practices. Know and follow all federal, state, and local regulations as well as school district guidelines for the disposal of laboratory wastes. Students should not eat, drink, or chew gum in the lab and should wash their hands after entering and before exiting the lab.
House flies, as well as all other flies, are insects that undergo complete metamorphosis. As seen in Fig. 1, this type of metamorphosis has 4 stages: egg, larva, pupa, and adult. Adult female flies lay eggs in clusters directly onto decaying organic matter. When the eggs hatch, larvae will emerge and feed on this organic matter. Fly larvae, also known as maggots, are legless and wingless, as well as creamy white in color. In other words, they look nothing like their adult counterparts. It may help students to understand this concept by comparing maggots/flies to another more common example of complete metamorphosis (e.g., caterpillars/butterflies).
On the posterior (back) end of the insect are 2 spiracles, which the insect uses for breathing (Fig. 2). Spiracles are to insects what nostrils are to humans. Many students will think that the 2 dark circles on their maggots are eyes. By observing the maggots’ movements, students will discover that these dark circles are, in fact, on the posterior (back) end of the insect. Students will probably find it amusing to know that maggots breathe out of their back ends! Maggots are tapered toward the anterior (front) end and have a pair of small mouth hooks, which they use to tear through food.
Maggots move through undulating movements. Students will observe that their maggots will not stay in the center of their cardstock paper; instead, they will move until they find the container’s edge. Maggots typically feed in large groups and, like many insects that exhibit such aggregation behavior, prefer to be in contact with another surface. This is referred to as positive thigmotaxis.
Maggots feed on decaying matter for several days before moving away from the food source and pupating. During the pupal stage, the insect does not feed. Instead, the entire body of the insect changes from a legless, white maggot into its adult form with wings, 6 legs, and large compound eyes. The entire length of this life cycle depends on temperature. House flies progress from egg to adult much more quickly in warmer temperatures than they do when exposed to colder temperatures.
House fly maggots are excellent examples of decomposers. These maggots can be found feeding on decaying organic matter such as dog feces and are responsible for cycling nutrients back into the soil.
Before class, pour a small amount of paint into 10 condiment cups. Each student will receive 2 cups, but you may use as many colors as you like.
Cut cardstock paper so that it will lay flat within a food storage container. You should be able to cut multiple pieces from a single sheet of paper. Each student should receive 2 to 3 pieces of cardstock.
Transfer at least 10 maggots into each of the 5 remaining condiment cups and distribute evenly among the class (1 cup for every 4 students).
Give each student a pair of gloves, 2 paint cups, 1 food storage container, and 2 to 3 pieces of cardstock.
Ask each student to place a piece of cardstock into the food storage container.
Have each student select a maggot and allow it to crawl on the cardstock paper (no paint). Have them observe the movement and ask them which end appears to be the head and how they came to that conclusion. Have them closely watch the way the maggot crawls. Once students know which end of the insect is the head, have them look for the tiny hooks the maggots have for mouthparts. With these observations, they should be able to answer questions 1 and 2 after the activity.
a. Optional demonstration:If the maggots are submerged in liquid, they will raise their posterior spiracles into the air like a snorkel. You may choose to demonstrate this to students by dropping a maggot into a container of paint.
Have each student take a maggot and lightly dip it in paint. Guide students through the following procedures:
a. Place maggot in the center of paper and watch where it moves.
b. Place maggot near the edge of the paper and watch where it moves.
c. Add a second maggot and see where they move; do they follow one another?
Have students predict what the maggots will do in each experiment. Note: Students may need to re-dip the maggot in paint between experiments and may need to switch out their cardstock paper for a clean piece.
Encourage each student to try his or her own experiment. For example, some students may want to see if the maggots behave differently if painted in a different color or if maggots will move toward or away from a drop of paint on their paper. Have students formulate a hypothesis and then run an experiment to test it.
Students should return their maggots to their shared condiment cup, discard their gloves, and leave their artwork to dry.
Have students independently answer the Analysis and Discussion questions.
Your teacher will give you a pair of gloves, 2 paint cups, 1 food storage container, and 2 to 3 pieces of cardstock paper. There will also be a cup of maggots for you to share with 3 other students.
Place a piece of paper into the food storage container.
After putting on a pair of gloves, choose a maggot from your group’s cup and let it crawl on your paper in the container. Carefully observe the way it moves.
Remove the maggot from the container and lightly dip it in one of your paint cups. Be careful not to drop it in the paint.
Place your paint-covered maggot in the center of the paper and watch where it moves.
Remove the maggot from the paper and re-dip into the paint cup. You may switch colors if you like.
Place the maggot near the edge of the paper and watch where it moves.
Choose another maggot from your group’s cup and dip in paint. Add to the paper with the original maggot. Watch their movements and see if they interact or follow one another.
Remove your painting from the container and replace with a clean piece of paper.
Think of a research question that you can answer with a small experiment. For example, does a maggot move differently if it is dipped in one color versus another? Be creative! Develop a plan for your experiment. You may use 1 or more maggots.
Run your experiment using the maggots and paint colors that you need.
Place all maggots back into the group cup, remove your gloves, and leave your maggot art to dry.
Answer the Analysis and Discussion questions.
Draw a maggot and label the front (head) and back (abdomen)
Drawings will vary, but students should label the tapered end of the maggot that contains the mouth hooks as the front (head) and the broad end with the posterior spiracles as the back (abdomen).
Maggots do not have legs. So how do they move?
Maggots move a lot like worms—they wiggle their bodies to get where they need to go.
When you placed a maggot in the middle of your paper, what did it do?
The maggot moved until it hit the wall of the container. It did not stay in the middle of the paper.Note: Because of their positively thigmotactic nature, the maggots will sometimes move underneath the paper after they hit the container wall, so students may have this observation as well.
What experiment did you choose to do? What did you think would happen? What actually happened?
This answer will vary, but make sure that students have a hypothesis and reasoning for this prediction.
Example: I wanted to see if insects would move toward a drop of paint placed on the paper. I expected them to move towards it because they might think it was another maggot. During the experiment, maggots ignored the drop of paint and did not move towards it.
Display maggot art in a “Larva Louvre Art Gallery” in your classroom.
Maggots can be rinsed in cold water, patted dry with paper towels, and then reared to adulthood. This will allow students to witness complete metamorphosis firsthand. For rearing information, please see our care instructions for house flies.
Students can share their experiments with the class, stating their experimental question, hypothesis, and findings.