Celebrate Halloween by Teaching about Creepy, Crawly Marcoinvertebrates

It’s Halloween in the Chesapeake Bay watershed! This is a perfect opportunity to introduce your students to the creepy creatures lurking beneath rocks in your local stream. While benthic macroinvertebrates may appear gruesome at first glance, a closer look reveals that these organisms are perfectly adapted to live and feed in their environment.

• Shredders, such as stonefly larvae, use their strong mouthparts to chew through leaves and twigs that fall into the stream from the canopy above.
• Collectors, such as caddisfly larvae, use specialized mouth parts to gather and feed on organic particles from the stream.
• Scrapers, such as mayfly larvae, graze algae from rocks. Some of these macroinvertebrates have strong claws that help them grip rocks in swift currents.
• Predators, such as dobsonfly larvae, have sharp mouthparts that help them eat other macroinvertebrates.

Benthic macroinvertebrates are often used as indicators of water quality because they inhabit almost all aquatic environments and have a wide range of tolerance to pollutants. Far from frightening, stonefly larvae (which are only found in pristine streams) are a beautiful sight to many stream biologists.

You can use the lesson plans below to begin your budding stream biologists’ love affair with bugs.

• Americorps Watershed Stewards Project - Stream Health Lesson Plans
• Project Watershed - Lesson Plan Introduction to the Biotic Water Quality of a Stream