Last week, I stopped off at a local library to peruse the section on field guides and natural history, and low and behold, there sitting on the shelf was a book on macro-invertebrates. Squeee! Okay, generally one refrains from squeeing at a public library, and when one does succumb to the urge, it is rarely about a book on insects.
Let's step back a few months...
Sometime in spring, I attended a meeting with the Valley of the Fox group of the Illinois chapter of the Sierra club. What drew me there was the volunteer activist group called the Water Sentinels, who every three months monitor the water quality of the streams throughout the county. I put my name forward. As it happened, one of the volunteers was relocating out-of-state, and a replacement was needed to cover the three site he monitored. Timing couldn't have been better. Not only did I volunteer to take the samples, but I offered to work in the lab, measuring the pH, turbidity, electrolyte, nitrates and phosphate levels.
Now chemical analysis is but one way to measure the quality of a body of water, the other method being biological. Usually this involves wading through the water with nets, collecting various organisms along they way, and then identifying and counting their numbers. Such organisms are usually referred to as macro-invertebrates, which is essentially all your insects, arachnids, crustaceans, molluscs and worms big enough to be seen with the naked eye.
Fast forward back to the present....
In reading the book, I came up with an idea. What if I collected some macro-invertebrate specimens from the local environment and learn to identify them? Furthermore, what if I tried to keep them alive in an aquarium, so I could observe their behavior and understand their requirements?
So one evening I gathered up some supplies - nets, jars, buckets - and with the two young minions in tow, headed to the banks of the Fox River. There we gathered rocks from the bed of the river, took water samples, and collected several minnows, flatworms, snails, waterboatmen, and one lone waterbug. Once we arrived home, we housed everything in an empty aquarium.
A couple of days later, I decided that the aquarium needed some plant life, and a greater diversity of insects. So I wisely put on my wellington boots, and visited a nearby pond, hoping to find something interesting. The bank of the pond was exceptionally muddy, and seemed determined to swallow my boots. I was able to gather up a few of the smaller plants - pondweed (Potamogeton nodosus), Common Arrowhead (Sagittaria latifolia) - digging up the roots with my bare hands. I took more water samples, collecting mostly water beetles in addition to some floating duckweed (Lemna minor). There where plenty of dragonflies in the air - ruby meadowhawks (Sympetrum rubicundulum), common whitetail (Plathemis lydia) - but I did not find any nymphs. Perhaps next time.
With a little rearranging, I added the plants, mud and all, to the aquarium, and poured in the beetles and duckweed along with the pond water. As the goal is to create a natural biotope - with prey, predators, plants and detrivores - there is no need to worry about contamination or quarantine. Whatever comes along for the ride can only be a plus.
Whether or not this little ecosystem can sustain itself, and for how long, remains to be seen. Eventually, it may need to be replenished with fresh livestock, or a cull or one or more species may be in order.
