Students will observe mealworms and earthworms and then make and record observations about their behavior.
Mealworms can be purchased at your local pet store. They are inexpensive and most are sold in amounts of 50, 100, or 200. The large mealworms cost more, but are more lively, making them easier for students to observe. The large mealworms are often treated with hormones to prevent them from becoming beetles. Inquiring whether the mealworms have been treated with hormones may be a good idea. The smaller and untreated mealworms will change into beetles in four to six weeks. Mealworms are also available from Carolina Science and Math at 1-800-334-5551 or http://www.carolina.com. Larvae are $6.70 for a pack of 50. Petco Store sells untreated mealworms $2.57 for 50 and four to five dollars for 100. Petsmart sells three different sizes of mealworms: 50 regular-sized or 35 giant or 25 super mealworms for $2.99 per type.
Earthworms can be purchased from stores that sells fishing tackle.
For an alternative to mealworms and earthworms you could observe pillbugs. Pillbug investigations can be found in:
All organisms have life cycles. Sometimes offspring do not look like the parent organism at first, but as they go through their life cycle, they begin to look more like the parents. Some organisms show direct development. This means they are born looking like the parent organisms, only smaller. As they develop, they change only by increasing in size until they are to the adult stage and look just like their parents. Spiders and earthworms go through direct development. Other organisms go through incomplete metamorphosis, which means they progress through three stages of development: egg, nymph, and adult. At each stage, they look different than they looked in the previous stage. Cockroaches and grasshoppers are two insects that develop through incomplete metamorphosis. A third type of life cycle is called complete metamorphosis. The insects' bodies change dramatically as they go through four stages: egg, larva, pupa, and adult. Mealworms and butterflies develop by going through complete metamorphosis.
Every organism responds to its environment or the surroundings in which the organism lives. Some behaviors are inherited or instinctual, while others can be learned.
The life cycle of mealworms will be observed and a journal will be kept to record their metamorphosis to adulthood as they become darkling beetles. Caterpillars' life cycles may also be observed and recorded as they change into painted lady butterflies.
Caring for Mealworms:
Mealworms can be kept in a covered plastic shoebox with holes drilled in the lid. Similar containers will work just as well, just so the mealworms have air holes for breathing. Bran or oatmeal can be used to line the bottom of the box and will serve as the mealworms food source. They will need a slice of apple or potato for moisture. Apples seem to last longer than potatoes. The mealworm habitat must be checked every day because the apple and potato slices tend to mold after a few days.
Mealworms need to be kept in a warm, but not hot, area. Do not place the container in direct sunlight. Mealworms move more slowly when the temperature is below 58˚ F. If you want to slow their growth process, they can be kept in the refrigerator for a short while. They will mature at a faster rate if they are kept in a warm area of 75˚ - 85˚F.
Mealworms also like to hide under things. A small bowl, similar to the aluminum tins that individual potpies are cooked in, tipped upside down in the habitat works well as a mealworm hiding place.
An additional habitat option is to use empty Cool Whip containers with holes punched in the lid. Inside the habitat would be the same as with the shoe boxes. Groups of students can have their own group habitats that they can observe.
Before beginning the Invitation to Learn and the investigations, discuss the differences of instinctual and learned behaviors. At the end of the investigations you will go over this again. Your discussion might include the following points:
1. Use Science Process and Thinking Skills
Invitation to Learn
In this activity, the students will be introduced to the mealworms and earthworms. They will study, sketch, measure, observe, record findings, and read about the worms. The students will be divided into pairs. Each pair of students will be given two heavy paper plates. One to three live mealworms will be placed on the first plate and one live earthworm will be placed on the second plate. If lightweight plates are used, make sure to put multiple plates together for sturdiness. Students may pair up to work together.
Next, give each student a copy of the Mealworm and Earthworm Behaviors worksheet. Allow the students to observe the worms as they move around on the plates. Have the students follow the directions on the sheet by observing, sketching, coloring, measuring and recording how each worm moves about on the plate and the sounds it makes as it moves. Encourage the students to gently pick up the mealworms and earthworms, then describe and record how they feel in their hands.
Upon completion of the Invitation to Learn activity, the students will participate in multiple investigations with the mealworms and earthworms by going from station to station using the Mealworm and Earthworm Behaviors sheet. If time is short, the investigations may be conducted on another day.
To complete the investigations, continue using the Mealworm and Earthworm Behaviors worksheet. Direct the students to conduct the investigations using the instructions included on the sheet as they move from station to station. Using the information the students read in the background information during the invitation to learn segment, students will determine whether the behavior they observe in the worms is learned or instinctual. At the end of the investigations, discuss with the class what they discovered and lead them to realize that because the worms are lower life forms, their behavior is largely instinctual. Their instinctual behavior was passed to them from their parent organisms (darkling beetles). Also, point out that the mealworms (larva) look entirely different from the adult beetles, while baby earthworms look like the adult worms.
The teacher must set up the time limits for each station. Five to seven minutes should be plenty of time for students to make and record observations. It is also advised to go through the stations with the students before letting them begin the investigations.
Station 1: Black/White using a mealworm &
Station 2: Black/White using an earthworm
Station 3: Light and Touch Response using a mealworm &
Station 4: Light and Touch Response using an earthworm
Station 5: Barrier Response using a mealworm &
Station 6: Barrier Response using an earthworm
Station 7: Moisture Response using a mealworm &
Station 8: Moisture Response using an earthworm
Station 9: Temperature Stimulus using a mealworm &
Station 10: Temperature Stimulus using an earthworm
Discussion after the Investigations
Observing and Journaling Mealworms' Life Cycle Stages
Additional mealworm and earthworm investigations:
Food Stimulus Station
Training a Mealworm
Painted Lady Butterflies
Observing the metamorphosis of the Painted Lady Butterflies is also a fun extension. Two useful websites are listed in the web sites section for buying and caring for the caterpillars.
Mealworm and earthworm cinquain poems can be written as language arts connection. A cinquain is a simple, five-line verse that follows a specific pattern. The pattern is:
Line 1 - one word of two syllables (usually a noun that names the subject of the poem)
Line 2 - four syllables (two-syllable adjectives describing the noun in line one)
Line 3 - six syllable (showing action)
Line 4 - eight syllables (expressing a feeling or observation about the subject)
Line 5 - two syllables (describing or renaming the subject)
Eating, growing, changing
Will become a darkling beetle
Wiggling, squirming, struggling
Trying to escape from the hook
Look for insects in the yard and garden that go through complete metamorphosis.
Haury, D. L. & Rillero, P. (1994). Perspectives of hands-on science teaching. The ERIC clearinghouse for science, mathematics, and environmental education. Retrieved January 14, 2006, from http://www.ncrel.org/
Lopez, R. E. & Tuomi, J. (1995). Student-centered inquiry. Educational Leadership, 52(8), 78.
Research has shown that hands-on learning in science will help students remember the material better because they are part of the learning process and not just spectators. While this is true for all learners, it can have a profound impact on students with difficulties such as second language barriers and learning and behavior disabilities.