Survivors: How Does Color Protect Insects from Predators?
How does color protect insects from predators?
- yardstick (meterstick)
- 4 pencils
- at least 82 feet (24.6 m) of string
- eight 12-inch (30-cm) chenille craft stems: 1 each of red, green, brown, black, white, orange, yellow, plus any other color you choose (These are commonly called pipe cleaners.)
- Find a large outdoor area with short grass. Measure a square with 20-foot (6-m) sides. Place a pencil at each corner of the square.
- Tie one end of the string to one of the pencils. Loop the string around each of the 3 remaining pencils, and tie the free end to the first pencil to form a marked-off plot of grass.
- Cut twenty-four 1/2-inch (1.25-cm) pieces of each color of pipe cleaner.
- Without letting your helper see, spread the pieces as evenly as possible in the marked-off plot of grass.
- Using the timer, instruct your helper to pick up as many of the pieces as possible in 1 minute.
- Count and record the number of each color found.
- Knowing that there should be 24 pieces of each color, calculate the number of each color not found.
Your helper found some colors more easily than others and probably did not find all of the pieces.
It is hard for your helper to find colors that blend in with the grass or soil. If the grass is the same shade of green as the colored pieces, your helper will have trouble distinguishing between the two. Some of the darker-colored pieces may blend in with the shadows of the grass or with the soil.
Insects with colors that blend in with their background are said to be camouflaged. Camouflage is color and/or patterns that conceal an object by matching its surroundings. Camouflage protects insects from their predators (animals that kill and eat other animals). For example, a bird that feeds on grasshoppers will have trouble spotting a green grasshopper on green grass.
In this activity, your helper represents a predator, and the colored pieces found represent the different insects the predator would eat. Coloring that helps to camouflage insects from predators is called protective coloration.
- How does the number of predators affect the survival rate of insects? Scatter the found pieces in the plot. Repeat the activity twice, first using five helpers, then ten.
- How does the color of the background affect which insects survive? Repeat the original experiment, using a plot of ground, half of which is not grass. Science Fair Hint: Take photos of the procedure and display the results.
Model the effect of protective coloration by preparing colored pieces of bread to represent differently colored insects. Peel off and discard the crust of 4 slices of white bread. Break each bread slice into 80 small pieces. Leave the pieces of 1 slice white, but color the others red, yellow, and green. For each color, mix together % cup (63 ml) of tap water and 10 drops of food coloring in a bowl. Soak the pieces of bread in the colored water, drain, then spread them out on separate trays. Allow them to air dry.
Choose an area with short grass where birds are often seen. Place 20 bread pieces from each of the 4 different colors on the grass. Spread each group in a circle of about 12 inches (30 cm) in diameter. Space the circles about 6 feet (1.8 m) apart.
Leave the area for 4 hours, then return and count the number of pieces of each color that have not been eaten. Subtract this number from 20 to determine the number of pieces eaten for each color. Repeat this procedure three times on 3 different days. Calculate the average number of pieces of each color eaten during the four trials by adding the totals for each color and dividing that total by 4.
Check It Out!
Some moths have markings on their wings that look like huge eyes. These markings can frighten away predators and are a form of protective coloration called warning coloration. Find out more about different types of protective coloration and examples of each. What is mimicry?
Warning is hereby given that not all Project Ideas are appropriate for all individuals or in all circumstances. Implementation of any Science Project Idea should be undertaken only in appropriate settings and with appropriate parental or other supervision. Reading and following the safety precautions of all materials used in a project is the sole responsibility of each individual. For further information, consult your state’s handbook of Science Safety.