Noticing the little animals

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This frog has sprouted legs, but needs more time before maturing to adulthood

Most of these blog posts are about Big Things, taking a whole-ecosystem or landscape-level view of wetlands. No surprise, as my PhD work was a big project advised by a big thinker. But, I do enjoy a close look at the little things, and in particular if I have a dip net with me at a wetland, it’s fun to get up close and personal with the animal life. At Christy Pond in Carroll County, I did just that.

You’ll most likely find the animals near plants which provide cover (shade, hiding space). Big “emergent” plants like cattail and bulrushes grow up out of the water, but how about Common Bladderwort (Utricularia macrorhiza)? This species holds pretty yellow flowers up in the air, but is a tangle of stems in the water. Attached to those submersed stems are bag-like traps (bladders) which catch and digest animals. (Admittedly, they will catch only really tiny animals).

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Bladderwort plant with aerial stem bearing flower, and a tangle of bladder-laden aquatic stems

You’ll find plenty of “primitive” or “lower” animals in a wetland pond. Sneer at them if you wish, but their lineage goes waaaaayyy back, and they have been very successful at what they do, for a very long time. For example, few animal movements are as graceful as a leech swimming, it’s like a ribbon undulating in watery flight. Snails adhere (even upside-down) to slippery, slimy surfaces, using a mouth shaped like a paint scraper to graze on surface growths.

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Medicinal leech with a bunch of snail comrades

Amphibian larvae (tadpoles or polliwogs) come in many forms, some hopping about on land in one season; some frogs take years to develop in the pond, becoming in some cases almost as large as your fist!

I should probably have a whole blog just for aquatic insects—so diverse in form and lifestyle and rich in species. Let’s look at this water bug as just one representative. Now, I’ve heard people refer to just about anything as a “bug,” from butterflies to earthworms (seriously!). But technically, a “true bug” is a particular type of insect with sucking mouth parts. Either as a member of the Hemiptera (“half-wing”) or specifically grouped as Heteroptera (“different-wings”), they all wear the mark of their clan on their back: a big X where the wings cross (one folded over the other). The leading portion of the wing (forewing) has a heavy, protective texture (it even looks like a shield!), while the trailing portion (hindwing) is thin and flexible. To my eye, this animal looks like a little, streamlined dinosaur. Fierce and beautiful.

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Water bug, ventral (belly) surface…sorry, I didn’t get a photo of the X-back.

If you visit this park, bring a snack. The wetland is on the lower part of the property, but near the street is the old farmstead. It’s a nice shady spot to rest, and you can even explore an old farm outbuilding. All in all, I’d call this an excellent spot to experience rural Iowa and its wetland life. Enjoy!!

Author: Paul Weihe

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

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