A Berlese funnel is a device that enables entomologists to separate the active stages of insects and other small invertebrates from a sample of moist soil, humus, compost, or leaf litter. The sample is placed in the funnel where it dries out over a period of days. Organisms living within the sample tend to move downward to escape desiccation and eventually fall into a container of alcohol beneath the funnel.
INSTRUCTIONS for making an inexpensive Berlese funnel from a plastic milk container.
For best results, collect a Berlese sample from a site that is somewhat sheltered and not subject to periodic flooding or desiccation. High population density and high species diversity can usually be found in:
- leaf mold associated with neutral soils in deciduous forests
- legume ground covers (colver, vetch, alfalfa, etc.)
- compost pile with a mixture of vegetable matter
- mulch from vegetable gardens or organic farms
A Berlese funnel should be set up in a location where it will not be bumped or disturbed. Excessive vibration or agitation will cause dirt to loosen, fall into the alcohol, and cloud the final solution.
Provide black and white construction paper for students to use when they examine their sample. Light colored organisms show up best against a dark background; darker organisms show up best against a white background.
Although the diversity of soil-dwelling arthropods is quite astounding, they can be divided into about 30 major taxonomic groups without too much difficulty. An illustrated key for identifying these organisms can be purchased from Vision Press, P.O. Box 5554, Raleigh, N.C. 27650.