“Hey, there’s a crayfish,” one student excitedly pointed out as they spooned the tiny creature from a tub of water sample.
“I don’t know what this is, but it’s something,” said another student who gingerly lifted a stick-like insect on a spoon. It turned out to be a water scorpion - perfectly harmless, but odd looking like a walking stick, but this one lives in water.
“They actually have a long hollow tube and when they are in the water, they face down and lift that hollow tube out of the water and get air," said Dana Strouse, a senior environmental quality analyst with the State of Michigan Department of Great Lakes and Energy. She visited Mrs. English’ exploratory insect class recently to help students learn more about insects and why they are important.
Strouse brought in four buckets of water - each collected from a local creek or lake. The sample included the leaves, twigs and other debris insects often use for protection. With plastic spoons and tweezers, students worked in teams meticulously searching through the debris and the water to find as many insects as they could. Some, like the crayfish, were easy to spot. Others, like a water penny beetle, looked like nothing more than a miniature penny - but something about it caught the curiosity of one student.
Strouse told students they would probably find mayflies, dragonflies, crayfish, beetle larvae, crane flies, snails and possibly even tiny leaches.
“We monitor macro invertebrates we find in the water samples to help us determine the water quality,” she said. Macro invertebrates are insects that, although they may be small, can be seen by a human eye without a microscope.
She explained how many insects in the larval stage live in water. “The dragon fly will spend up to two years in water in their larval stage,” she said.
The insects class not only helps students understand the many different insects, but also how they are valuable to the ecosystem. “Why are invertebrates important to aquatic biology?” asked Strouse. “They’re fish food. If there are no insects in the water, the fish have no food and if they have no food, they will move on to somewhere else. These invertebrates can help tell us a lot about the water quality in an area.”
When she conducts water sampling, she showed students the list of the many different types of aquatic invertebrates she looks for. She counts and identifies each type in her sample and that helps her determine the overall water quality index.
This exploratory class is designed to help students identify different insects and understand the physical characteristics of insects and how the roles the insects play in providing a balanced ecosystem.