You can purchase mealworms inexpensively at a pet store as they are often used as food for birds or lizards. To allow first graders to experience complete metamorphosis, you will need to commit to having a home for the mealworms for two to three months. The larvae stage lasts up to 10 weeks but when you purchase mealworms at a pet store, they are often advanced in the larvae stage and will transform to pupa in two to three weeks. Divide first graders into groups and provide them with a shoe box. Allow them to use crayons or markers and decorate the outside of the box as a home for their mealworms. Give each group about 1 inch of oats, bran or cornmeal in the bottom of the shoe box. Punch a few small holes in the top of the box for air. Divide the larvae between the groups and have students place them in the new home. Store the boxes away from direct light or high heat. Every few days, have students observe the larvae and make note with words or drawing of any body changes in a science journal.
An ideal temperature for mealworms is about room temperature, or 76 to 80 degrees Fahrenheit. If you raise or lower the temperature by five to 10 degrees, you can effect the rate at which mealworms mature without harming them. Explain this to first graders and allow them to observe or assist as you set up a class experiment. Take a few mealworms and put some in each of two boxes along with the bran or oats. Label one box with "Warmer" and one "Cooler" and write the date on both. Place the cooler box near an air conditioner or other cool location no lower than 62 degrees Fahrenheit. Place the other in a warmer location such as near a sunny window or under a bright desk lamp. Once a week, have groups of first graders observe the two boxes and draw pictures of their observations in a science journal.
Once the mealworms mature into beetles, have first grades refer to their science journal sketches and use it as a reference to assist them in drawing a picture or making a model of the beetle life cycle. First graders can label the parts of the life cycle with assistance in the form of a word wall list spelling the life cycle stages. Have them label pictures directly on the drawing. For first graders who want to make a model, have them use modeling clay to create the life cycle parts. The life cycle parts can be glued on pieces of cardboard then labeled with words written on the cardboard.
Have first graders observe the mature beetles during a lesson on the parts of an insect. Place an insect in a small, clear container for each student or small group so students can closely observe them. Instruct first graders about the three body parts (head, thorax and abdomen) and six legs all insects have. Ask students to observe these parts on the live beetles. After observation and the lesson, have first graders draw a picture of the beetle and label the insect body parts.