Insect Orders
Insect Identification: The Basics
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Sampling Tools and Methods
The most important tool you will use is a net. The type of net you use will depend on where you are planning to scoop. All of the nets should be very sturdy and the shaft should have a length of at least 4 feet. In slow-water environments a D-frame or O-frame aquatic net should be used. In a fast-moving water environment a large rectangular kick net should be used. To sort the sample, the easiest tool to use is a light colored pan.
When sampling in a pond or other slow-moving body of water, the best technique is to sample the submergent vegetation (the vegetation under the water). Avoid scooping too close to the bottom. Most aquatic insects can be found at all levels of the pond and if mud is scooped into the net or pan it will be very difficult to see any insect at all. Scoop in a sideways motion, being careful not to fall in. (Figure a.)
In the early spring, the first visible life was on a sunny day in which the temperature was above 42 degrees Farenheit. A number of aquatic beetle adults, and dragonfly and damselfy nymphs were present. But when the temperature dipped or the sun was hidden by clouds, all of the aquatic insects vanished. I believe they buried themselves in the debris on the bottom, but I was unable to confirm that.
When sampling in a river or other fast-moving body of water, the best technique to use is called the kick method. While wearing waders, walk into the water with a large rectangular net. Face down-stream. Hold the net so the rim touches the bottom and the opening of the net faces up-stream. Then begin to kick the bottom substrate (silt, gravel, etc.), allowing the material to flow into net.
With either method, one important thing to keep in mind is to not over fill the net. If that happens it will be hard to lift the net out of the water, and then to sift through the massive amount of substrate to find the insects.
After collecting the substrate in your net do not simply look in the net for the insect. As Figure b. illustrates, the insects' camouflage can make it very difficult to see them. To counter this, use a light colored pan (Figure c.). Place of the plants into the pan and swirl them around. Then let the substrate settle and visually look for the insects, they will move around and be easily spotted. To sort the insect you can scoop them up using jars with caps; but a cost effective way is to scoop them in yogurt cups (Figure d.).
Remember to return the substrate from where you got it!
If you want to take the samples back to the lab keep them in separate containers. Place those containers into a bucket. The reasons for keeping the insects separate are so you don't have to reseparate them in the lab, and so the insect don't eat each other while in transit.