Critter Crawl

For recent weekend science fun posts we have had a couple of walks: a spring flower walk and a flowering tree walk. Now it is time for a change of pace and do a critter crawl.

Have you ever dug through a pile of leaf litter or looked under a log? How about sifted through a compost heap? Take some time to find a quiet, preferably moist, spot where pieces of dead plants are piled and spend a while getting to know the small, but important animals that live there. Prepare to be amazed at how many different tiny creatures dwell in this often-ignored part of our world.

Before you get started, you might want to gather up a few items:

• A magnifying lens can help you see more details
• Tweezers, forceps or a small stick to gently move leaves or bark
• Small paintbrush to remove dirt and move tiny creatures
• Paper and pencil to make drawings and record results
• Gloves (optional but helpful)
• Identification guides, or take a look at descriptions of compost critters like this one at the Junior Master Gardener website

Locate a compost heap, pile of leaves or logs where you have permission to explore. First survey the area. Make sure you and your family are familiar with common poisonous creatures such as snakes or scorpions that might also be found hiding under leaves, rocks or logs in your community. Bees and wasps sometimes nest in the ground too, so exercise caution.

Gently begin to turn over leaves or peel off loose bark. Pay close attention. What kinds of things might you see?

Expect:

• Insects such as beetles, crickets, cockroaches, ants or earwigs
• Snails, slugs
• Spiders, mites
• Millipedes, centipedes
• Worms

If you are lucky you might find a few creatures that are children’s favorites, the rolypolies or sowbugs (also called potato bugs, wood lice and various other names). Depending on the type, rolypolies and sowbugs are 1/4- to 1/2-inch-long, gray and relatively hard shelled.

If you find some, gently pick one up. How does it react to being picked up? Does it roll into a tight ball? If so, then it is a rolypoly.

Does it simply try to scamper away? Then it is likely to be a sowbug. Sowbugs look similar to rolypolies, but lack the ability to curl up tightly.

The rolypolies and sowbugs belong to a group of animals called the Isopoda. “Iso” means same, and “poda” means foot. Carefully tip yours over and see if this name fits. Does all its feet look the same? How many legs does it have? Insects have six legs and spiders have eight legs, do you think it is either of those?

Does the isopod have eyes? Does it have antennae? What are those small spikes sticking out from the rear part?

When scientists carefully examined isopods, and then compared the isopod appendages and other characteristics to those of other groups of animals, they figured out that isopods are closely related to crabs, shrimp and lobsters. They are crustaceans. Tiny crustaceans in your garden or compost heap, isn’t that cool?

What happens when you set your isopod back down? Does it run towards the light or away from the light? Does it try to hide or does it curl up? Try thinking up some more questions to ask.

Keep looking through the litter. You will probably encounter a few things less familiar than the rolypolies, but no less interesting. Have a lot of fun while you observe and learn about this hidden world.

If you can’t get outside this weekend, then pick up a few books, like the ones suggested below. After reading them, crawl around the house pretending to be earthworms, crickets and isopods.

Rolypolyology (Backyard Buddies)
by Michael Elsohn Ross, Published by Carolrhoda Books, Inc. Minneapolis, 1995. ISBN 0876149018 contains detailed information and ideas for experiment with isopods.

Compost Critters
by Bianca Lavies, Published by Dutton, 1993. ISBN 0525447636 has absolutely stunning photographs of the inhabitants of a compost heap. Amazing!