Show a real wood bug. Ask if students have seen them before in parks or gardens.
Ask what are the needs of an animal to stay alive? (food, water, shelter). Wood bugs have these needs too.
Class discussion of the needs of wood bugs (food, water and shelter), including where they like to hide, and what they like to eat. This discussion can be based on experiments done in class (see other activities in the lesson plan), and/or by a walk to find and observe wood bugs in their natural environment (wood bugs are easily found in the fall or spring under logs and rocks in gardens and forests).
Wood bugs’ food is rotting wood and leaves, so wood bugs are often found in the upper layer of a compost heap.
Wood bugs need water, as do all living things, but wood bugs have a special need for water. Wood bugs are closely related to ocean-living crustaceans such as shrimp. Like these ocean animals, they have gills - using them to extract oxygen from water. Because of this, they always need to be in a moist environment, and will die fast if they dry out.
For shelter, wood bugs like to live in moist dark places, such as under paving stones, rocks and chunks of rotting wood.
See reference for more information and different kinds of wood bugs: http://en.wikipedia.org/wiki/Woodbug. I believe I collected wood bugs from these three families: Oniscidae, Porcellionidae and Armadillidiidae (pill bugs, which roll into a ball).
Students set up a wood bug habitat which should include a layer of damp sand, to keep the habitat moist, ideally a piece of rotting wood for a hiding place (wood bugs also eat it), and a few composted leaves for food.
Wood bugs are added to the habitat from the walk, previous experiments, or from a collection made by the teacher in advance. Take care of this living thing: do not pick up the wood bugs with your fingers as they are very delicate. Use a paintbrush if you need to move them around.
Review by asking students to check that their wood bugs have damp sand to keep them moist, so that they can get oxygen. Ask students to check that they have a place to shelter, and food to eat. Lastly put the lid on.
Students continue to take care of their wood bugs. Note: it is important that the rotting leaves do not grow mould - remove any that do. The habitat needs to be moist but not soggy. A habitat can be kept for just a week, or several weeks. If kept for several weeks, babies may be born in the habitat.
After a week or two, look for evidence of the wood bugs eating (food with nibbles out of it), excreting (brown spots of fecaes under the wood), growing (a shedded exoskeleton), having babies (new baby wood bugs; the eggs are too small to see with the naked eye).
When the habitat is ready to be dismantled (after a month or months if they are doing well in the classroom), they need to put back where they came from (assuming it is warm enough - spring and fall are when wood bugs are not hibernating, so the best time). Could be combined with a decomposer hunt activity.
Students use a paintbrush to flick the wood bugs from their habitat into a garden or sheltered spot.