The Craziest Critter that Lives in Your Creek

Photo supplied.
A case made out of rolled vegetation caddisfly peeking out at left.

Can you imagine taking a pile of rocks, stitching them together with silk into a tube, then crawling inside and calling it home?  You’d be safe from predators, and you’re not stuck in one spot, you can stick your feet out and walk around with your home going everywhere you do.  Now how about your cousin Cam, he just rolls himself up in a leaf and calls that home. And then there’s cousin Carl who lives in a windy area, he uses larger stones, stitches them together with silk and glue, and then attaches them to a boulder so he and his home won’t blow away.  Clever cousin Cathy weaves her silk into a butterfly net and sets it out in the wind to catch food.  When she’s hungry, she simply picks food out of the net to eat.

Science fiction you say?  Nope.  A child’s fairy tale? Nope.  These are real life, and they’re happening in Millbrook today!  Underwater that is, in the streams, ponds, and tributaries that make up Baxter Creek.  These are the caddisflies, close relatives of butterflies and moths.  All caddisfly larvae (like the caterpillar to the butterfly) live under water, so imagine a miniature underwater version of the examples above.  If you still have trouble imagining these critters, ask any kid that comes home with wet feet. They have likely seen these and other amazing little critters while playing in the creek.

The tubular case making caddisflies are the easiest to find.  Each family has a unique case design partly dictated by the materials available in the creek.  Cases might be constructed of sand grains, tiny shells, bits of wood, or various plant parts, sometimes leaves that are rolled and stitched.  Members of one family are often mistaken for snails, building spiral cases out of grains of sand.  Cases attached to rocks in fast flowing water are built by the saddle case makers, the larger bits of rock and a dome shape all help to keep these homes from being swept away in the current.  The net-spinning caddisflies create funnels out of silk that look like a spider’s web shaped into a butterfly net.  These funnels face upstream, and the current literally delivers food to them.

Within a year or two each caddisfly larva will seal itself into a cocoon and become a pupa.  just like a butterfly, the adult will emerge with wings, and live above water for about a month.  Their purpose is to mate and lay eggs, sometimes diving back underwater to attach their eggs to objects.

Caddisflies are an important food source for trout and other fish. They are sensitive to pollution, and so indicate the health of lakes and streams.  The next time you are walking along Baxter Creek, pick up a rock and have a look for one of these amazing critters.  Contact the Millbrook Chapter of Trout Unlimited if you’d like to learn more about what we do, and what we can do for you! Troutunlimitedmillbrook@gmail.com.

Photo supplied.
Northern casemaker head and legs out of case climbing over another.

Photo supplied.
A saddle case maker flipped over revealing the cocoon inside.

Photo supplied.
Net-spinning caddisfly funnels collecting food in current.

By Brian Round, Trout Unlimited Millbrook

Tagged . Bookmark the permalink.

Comments are closed.