III.B.1 Part Two--Make a Berlese Funnel

The Berlese funnel trap (pronounced ber-lace-ee) is named after an Italian entomologist who invented the trap more than100 years ago. Berlese funnel traps are essential to scientists who study very small organisms that live in leaf litter. These animals prefer moist, cool conditions and rarely leave the cover of dead leaves. A Berlese funnel works by changing the preferred conditions of leaf litter organisms and forcing them out. As a light bulb in the trap warms up the plant material, the animals seek a cooler, wetter place to hide, and they fall into your trap!

A Berlese funnel should take approximately 20-25 minutes to make. Each team of 2-3 students should have one.

Materials needed (for one trap):

• One 2 liter plastic soda bottle
• Knife or scissors for cutting the bottle
• One moistened, white paper towel
• Paper clips, tape, or bamboo skewers for attaching the funnel
• Circular piece of stiff wire screen approximately 3 inches in diameter with holes big enough for insects and animals to pass through. (Window screen will not work because it is too flexible and the holes are too small.)
• One incandescent light bulb (Gooseneck lamps work well. Do not use florescent lights!!)
• Small container such as a film canister of rubbing alcohol for preserving insects (optional)
• Magnifying glass for observing trapped animals

Directions: Cut the neck of the soda bottle off where it begins to curve into the bottle. Save the top. Place a white piece of moistened paper towel into the bottom of the bottle. This will give your creatures some moisture and make them easier to see. Take the top and turn it upside down to make a funnel. Put the funnel into the soda bottle so that the top edges are flush. Secure the funnel with tape or paper clips. Take the piece of wire screen and fit it into the funnel about 2 inches from the top edge. Put in a small handful of leaf litter. Place the incandescent light bulb a few inches over your trap. Allow it to warm and dry the leaves overnight. To observe your live animals more closely, remove the funnel and leaf litter carefully and quickly cover the bottle with a plastic bag. Gently turn the bottle over and shake the contents into the bag. Secure the bag opening and examine your specimens! If you prefer to preserve your collection and examine nonliving animals, tape a small container, such as a film canister, under the spout of the funnel. The animals will tumble into the rubbing alcohol and stay preserved until you are ready to look at them under magnification.