Activity

Wood bugs: where do they like to live?

Summary
Set up simple habitats in the classroom with various places for wood bugs to hide, or hunt for wood bugs outside, to determine where they like to live. Students document the most frequent hiding places and deduce where wood bugs prefer to live.
Science content
Biology: Features, Adaptations of Living Things (K, 1, 3, 7)
Biology: Food Webs, Ecosystems, Biomes (3, 4)
Materials

For outdoor activity:

  • season that wood bugs are abundant i.e. early fall and spring/early summer (not cold, but not too hot, and moist)
  • area to explore with dead leaves, logs, sheltered spots at the base of buildings
  • worksheet to record where wood bugs are found (attached)

For classroom activity:

  • clear sided containers (e.g. salad container) with small holes punched in the lid (for habitat). Ideally one per table group, or one per student with small classes
  • sand, enough to cover each habitat to a depth of about 1cm
  • water to dampen sand. Ideally use water from a puddle or pond. If tap water is used, leave it to sit for a few days to allow chlorine to dissipate
  • rotten wood chunks that are damp, one per habitat box (e.g. cedar or other wood that wood bugs are found under) to fit in habitat
  • small rocks, one per habitat
  • wood bugs, enough for at least 3 per habitat. Add to box early in the day to settle
  • stickies - 1 per wood bug for habitat choice graph (stick on box lid for start of lesson)
  • pencil for each student (on box lid)
  • class chart with enough spaces for all boxed wood bugs
Procedure

For outdoor wood bug habitat hunt:
Students to look for wood bugs, and record where they find them and the conditions (damp/dry, light/dark, warm/cool).
From their data, conclude where wood bugs like to live, and what conditions provide an ideal habitat for them.

For indoor classroom activity:
Set-up prior to experiment: at least one hour before students come into class, set up a habitat on each table group. Each habitat is a clear container with a layer of damp sand on the bottom, a chunk of rotten wood, a rock and five or so wood bugs.
For the lesson, provide each table group with a number of sticky notes corresponding to the number of wood bugs in their habitat. At their desks, each group counts how many of their their wood bugs are under the wood, how many are under the rock and how many are out on the open sand - they will need to gently lift the items to find all the wood bugs.
Students record their results by using one stickie per wood bug, and writing where they are on it (sand/wood/rock). Each group adds their sticky notes to form the columns of a class bar chart.

A classroom discussion with the bar chart determines where the wood bugs most like to live. Usually the wood is preferred over the rock. Why? The wood is a shelter for the wood bugs - it is a dark hiding place. The wood is also a little moist, so keeps the wood bugs damp. (Wood bugs get oxygen from water with their gills - they don't have lungs - so they always need to stay in damp places to survive. They evolved from animals that lived in the ocean, and have retained their gills unlike many other land animals.) In addition, the wood bugs might like to eat the wood.
Wood bugs are also often found on the sand, or maybe burrowed into it. The sand is damp, which they prefer.
Usually the wood bugs are not found under the dry rock, though sometimes they are.

Then ask students to modify the habitats to make them the best for the wood bugs - the rocks can be removed if wood bugs were not found under them, or left if they were. If a lot of wood bugs were found under the wood, add more wood pieces to each habitat. Whatever the results, the sand should be kept in the habitat as it will keep the environment damp.

Conclude that we have given the wood bugs a shelter that serves their needs. If the wood bugs are to be kept in the classroom, they will need food as well - either conduct an activity to determine what wood bugs like to eat, or alternatively, after discussion that wood bugs eat dead plant matter add some wilted lettuce or potato to the habitat.

Notes

Tricky for kindergarteners to record where 3 wood bugs are in their habitat and report back to class.

I have had very variable results with this activity - if the wood bugs have been recently disturbed, the wood bugs just want to hide and do not care much where, so make sure they have time to settle. It is best if after this activity, wood bugs do have a piece of wood in their habitat, as they eat it as well as hide under it. So if only one or two wood bugs are under the wood, do include the wood in all habitats.

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