Wood bugs: what do they like to eat?

Students each have a live wood bug and test what kind of food they like best: fresh leaves, or composted leaves. The students add their results to a group graph. The results can be used to feed wood bugs kept in class.
Science content
Biology: Features, Adaptations of Living Things (K, 1, 3, 7)
  • wood bugs, enough for one per student (in a lesson, use the one from the wood bug observation)
  • large petri dishes, or similar flat clear containers with lids, one per student
  • fresh salad leaves
  • partway composted leaves e.g. forest floor litter
  • optional: potato slice (wood bugs seem to love it!)
  • stickies - 1 per student for recording food choice
  • pencil for each student
  • class chart for recording wood bugs' food preferences

Note: I am not doing this activity much any more - it is not good science.
The wood bugs in the food-choice dishes are too unsettled to actually be choosing the best food to eat.
Make a discussion instead about the role of wood bugs (vegetarians) and other decomposers - add these foods to the habitat and look for evidence of any of them being eaten.

Set-up prior to experiment: a large petri dish with fresh leaves, composted/rotten leaves (freeze lettuce for an hour to speed up decomposition) and potato slices. One dish per table group works well.
Wood bugs, one per student in closed containers kept moist with a layer of wet tissue.

Students tap their wood bug into the petri dish with the food choices, and put on the lid. Adults can help by gently pushing the wood bug with a paintbrush if necessary. Cover so that it is dark inside, and leave for a while.

Class discussion or another wood bug activity while the wood bugs to adjust to their new environment. Ideas to discuss: Talk about how different animals eat different things.
Optional prediction: students are asked to predict whether wood bugs would prefer the fresh salad leaves or the partway rotten leaves. For younger age groups, it is best if predictions are done anonymously: ask students to close their eyes, and vote by raising their hand. Class predictions are recorded on the board. A second vote of what the students might like to eat for their own dinner given the same choices lightens up the heaviness of predicting at this age, and gives some thought to how different animals might have different food preferences. (Note: I would recommend skipping this prediction step if the students have not already done a lot of hands-on science with careful observation and recording already. Accurately seeing and recording scientific phenomena is the first step to be mastered, before adding the complexity of thinking ahead and predicting).

At their desks, students are given a sticky note for each wood bug, then they can open the dishes. They look where each wood bug is found when they first open the dish (they are likely still moving around), and write each wood bug location on its own sticky note. Students may need help finding the last wood bugs if they are hidden under leaves.

Each student adds their sticky note to a class bar chart, above the correct food choice column. There is much variability in what food the wood bugs are found on (realistically because the wood bugs are more interested in escaping this foreign environment rather than choosing what food to eat).

The results of this activity can dictate what food to add to a classroom wood bug habitat. Even if no wood bugs were on potato, make sure that some is added to the habitat (wood bugs seem to potato it a lot).


The food choice can more simply be given in the habitats once they are set up. Students give wood bugs food choices and observe what they like to eat over time.

Grades taught
Gr K
Gr 1
Gr 2
Gr 3
Gr 4
Gr 5