Most soil animals are very small. As a result, we don't know much about them. Simple questions like where they live haven't been completely answered. Part of the problem is that larval stages do not look like the adults. Maggots for instance, do not resemble flies. The Tullgren funnel is one method used to separate soil animals from leaves. A light bulb applies heat and light above to leaves, or other materials. Animals moving away from the light bulb are trapped in a vial below. This is a good method for larger animals that can survive the heat. Beetles, springtails and fly larvae are often recovered. Smaller animals frequently dry out and die. Animals trapped in moisture on the sides of the funnel also die.
Soil animals are classified by size. Larger soil animals (macrofauna) include burrowing animals, insects, slugs and snails and earthworms. Middle sized animals (mesofauna) include spring tails (collembolan) and mites. The smallest animals (microfauna) include nematodes.
The most common animals in mushrooms are collembola, fly larvae, beetles, and mites. Millipedes and nematodes are also extracted sometimes.
Earthworms are segmented and larger than most other soil animals. The "nightcrawler" shown here is not native to North America. They dig deep burrows and are very important in decomposition. By mixing soil and organic matter, they have changed the layered structure of some forest soils. I have never isolated one from a mushroom.
Collembola are primitive wingless insects, usually less than 2 mm long. The "spring" under the abdomen and short, thick antennae are distinctive. They have six legs and are white or grey.
The most common fly larvae are white with black heads. They lack legs or antennae. Their bodies are segmented.
Beetles have six legs, antennae, a head and three body segments. They are usually reddish brown or black. Beetle larvae have white, soft, segmented bodies. The six legs are just behind the head. The head is a hard, reddish capsule.
Mites are rarely longer than 1 mm and difficult to see with the naked eye. They are reddish and have eight legs. They do not have the narrow waist between their abdomen and thorax that spiders have.
Millipedes have tube-shaped bodies made up of many segments. Each segment has two pairs of legs (4). The antennae are short. Centipedes in contrast have one pair of legs per body segment.
Nematodes are extremely thin, and range in length from 0.5 to 1.5 mm. They do not have segmented bodies like earthworms. They are transparent (clear).
Among the questions that can be answered using the Tullgren funnel are:
To get the best results use multiple funnels. By chance one funnel may give a very high number, or a very low number. You can calculate the average by using more than one funnel. You might want to read designing experiments before starting.
|Ring stand support for Tullgren funnel.
|Wood rack for Tullgren funnel.
You can calculate the average by dividing the total number by the weight of mushrooms in all of the funnels. For example: 500 individuals divided by 5 kilograms=500 ÷ 5=an average of 100 animals per kilogram. Remember you cannot calculate an average from only one funnel.
Last update: 19 Nov 06. © 2006. Robert Fogel, Ivins, UT 84731.