Fun with a dip net

Can you spot the Arthropods? (hint: look for a “chitinous exoskeleton“)

In a recent wetland visit, I was reminded of the fun we had at the nature center back in my college days, when we gave a “pond tour.” Picture a bunch of school kids or families gathered around a pond with dip nets, catching frogs, snails, insects, whatever. We had pans or trays of water to hold the organisms and sometimes even microscopes or magnifying lenses for close-up viewing. Fun times!

At Westmoreland Wildlife Area in Pocahontas County, a low spot in the wetland, nearest the road, was deep enough to over-top my hip boots. I nevertheless mucked about, catching biota and snapping pix—all for your benefit, dear reader. But, I confess…it was also fun. Let’s meet some of those wetland residents, shall we?

In the photo at the top of this post, notice the bug-eyed animal at the top left corner. You can easily count the six legs (that’s an insect, all right) and notice the three paddle-like extensions from the tail end of the abdomen; those are external gills. We are looking at the immature (nymph) stage of a Damselfly. Together with Dragonflies, these insects are in the Order Ododnata. You can find lots of great information about these fascinating animals at the U. of California-Berkeley web page. In a pond tour, I liked to show participants their amazing hinged jaw: it swings out from the head, extending the reach of this predator. The adults have amazing flying ability, as I have noted previously.

Also in my container are a couple crayfish (crawfish? crawdads? Whatever). Everyone always fixates on those ouchy pincers, but they have really long, sensitive antennae and work them expertly—fun to watch. Even more impressive is their ability to “jump” backwards when threatened: the fins at the tail end spread wide to push against the water, and the abdominal muscles are fast and powerful, causing the tail to “snap” underneath the belly, propelling the animal backwards—fast as a rocket! These guys also have a really pretty pattern I like very much as well.

Mollusks (snails), insects, maybe an Ostracod (“Seed Shrimp”). Quite a haul!

The dip net brings up quite a variety of invertebrates, actually. I paused to photograph my hand with several. In particular, notice the snails. For convenience, we might broadly classify the shell shape as either flattened (“rams-horn”) or conical (spiral). Examples of each type are present in my palm. Both conical snails here have the same chirality (“handedness”), being dextral (“right-handed”). That chirality is the same as a standard screw, is the more common form for snails as well. Interestingly, just a couple years back, researchers published about the genetic determination of chitality in a common snail. I find it interesting that we’re still learning about things like snail shell development. Isn’t science awesome??

Polly-wog or tadpole? You decide!

Speaking of awesome, how about the pearlescent belly on that tadpole? I’ve looked at plenty of immature amphibs having a light-colored belly under a dark topside. But never before did I notice one glowing so beautifully in the sunlight (my photo doesn’t really do it justice). Be aware, this animal is quite vulnerable out in the air—I immediately returned it to the water after snapping this photo.

I could wax poetic about the pond, but let’s think about the bigger picture. The pond is a deepwater habitat grading into a shallower water habitat, grading to a semiaquatic habitat lacking standing water (but with waterlogged soil). It’s part of a continuum, as wetlands should be. Better still, this is part of a whole wetland complex. I chuckled at the “dueling wetlands” located directly across the street from each other, but I’m delighted that these are part of an even larger, 519-acre (210-hectare) Varina Area Wetlands Complex. The signs indicate cooperation between the Iowa Natural Heritage Foundation and the County Conservation Board. I hope to further explore these areas in the future. If you have visited there, please tell us about your experiences in the comments! Thanks…


Author: Paul Weihe

Associate Professor of Biology at Central College, traditional author (Textbook of Limnology, Cole & Weihe, 5th ed.; Waveland Press), and now...blogger!

One thought on “Fun with a dip net”

  1. Thanks for the memories. It has been too long since I looked at wetland critters in a white pan.

    And that tadpole is just gorgeous. It seems to be showing us an entire dark starry sky, including a galaxy. We humans could live twice as long and still not run out of wonders to contemplate in wetlands, if only we had the time.

    Liked by 1 person

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