Sifting for Leaf Litter Arthropods
Leaf litter arthropods are one of the most abundant forms of animal life in temperate deciduous woodlands (and shrubbery beds and compost piles, etc.). They are easy to find and interact with in fun, creative ways. Short of investing in Berlese or Tullgren funnel techniques as used by scientists (incidentally, these techniques by necessity for taxonomic study, kill the arthropods captured), one may sample this rich diversity of life with simple, inexpensive home-made tools.
The basic tool is a screen of some sort that will allow you to separate the larger leafy material from the tiny arthropods so that the arthropods can be seen. [need to continue...
Now that lots of little arthropods are crawling about on the white surface, what can you do with them? First, I suggest you spend a little time watching them crawl around and just enjoy the show. The creatures have interesting shapes, colors and movements. For nothing better to do, try your hand at capturing a few of the screened arthropods (you can release them immediately or after you have finished observing them in a collecting dish or jar). A standard collecting tool is the aspirator [google "insect aspirator" for more info]. Aspirators are nice and quite efficient for collecting large numbers of small arthropods, but in my experience a significant number of arthropods captured with this method are killed--apparently on impact when they hit the walls of the vial. Aspirators are also challenging to construct with home materials. A worthy alternative to the aspirator, especially for minimizing damage to the live animal, is a paper funnel.
The paper funnel is an excellent tool for capturing freshly screened, active leaf litter arthropods. Spiders, centipedes, and more will walk right into the mouth of the funnel. All that is required is a little herding action on your part as you manipulate a small probe (leaf fragment, slider twig, or even your finger works as a probe) to direct the bug of interest into the funnel. Even those fast jumping springtails are easily caught with this method. Position the mouth of the funnel near the springtail and with your free hand, gently provoke the springtail to jump. Nine times out of ten, the springtail will jump into the funnel. Once the little creepy crawly is in the funnel, simply move the narrow opening over a collecting jar and give the funnel a few taps. The creatures fall harmlessly into the jar. If you are collecting springtails, make sure your collecting jar is tall enough so that the springtails can't readily jump out. Use a number of collecting jars if you wish to separate the various types of creatures. A slightly moist tissue in the bottom of the collecting jar will help keep the critters alive until you get back to your lab space.
Click here for a paper
funnel pattern.
Print out the paper funnel pattern and instructions provided at the link above.
Once you have formed the funnel, you may want to flatten it so that it packs
well for transport. Funnels flattened with two crease lines readily pop
open when the creased edges are squeezed towards each other.
After children have seen a few arthropods, the funnels can be turned into artwork. See the examples linked below:
Decorated paper funnel 1
Decorated paper funnel 2
A word about paper thickness for the funnel. While thicker papers, e.g. construction paper or card stock, will make sturdier funnels, multi-purpose office paper, as is typically found in most printers, is best because it is thin and smooth. Being thin, the paper offers little hindrance to to crawling arthropods entering the funnel. Being smooth, the inner walls of the funnel offer little support to would-be clingers so that all arthropods should slide more easily down the funnel into the collecting jar.
Other Resources:
http://cbc.amnh.org/center/pubs/pubscbcinverts.php?npid=8 - pdf of "Life in the Leaf Litter" from the American Museum of Natural History
Leaf Litter Activity from Discover Life in America
.