BerleseTullgrenFunnel

The Berlese-Tullgren funnel, commonly called the Berlese funnel, is a laboratory apparatus used to extract terrestrial invertebrates from soil, leaf litter, moss, and other small substrates. It enables researchers to sample microarthropods such as mites, springtails, and small insects by driving them away from a drying surface and into a collecting vial containing a preservative.

The technique relies on a desiccating gradient created by heat or light. As the substrate is heated or illuminated, organisms move downward in search of moister conditions. They pass though a fine mesh or funnel into a collecting jar or vial, which is filled with a preservative such as ethanol, glycerin, or a suitable fluid. The collecting vessel is placed beneath the substrate screen to receive the fauna.

Construction typically includes a funnel body with a substrate screen, a second screen to hold the sample above a collecting bottle, and a heat or light source positioned above the sample. The collecting bottle is filled with preservative. Variation exists in mesh size, preservative type, and heating method (electric heater, incandescent lamp, or warm air), but the basic principle remains the same.

Applications include surveys of soil fauna for ecological and taxonomic studies, biodiversity assessments, and some forensic entomology contexts. The method was developed in the late 19th to early 20th centuries and is named after Julius Berlese and Karl Tullgren, who contributed to its early formulations. Limitations include potential bias toward mobile or heat-tolerant taxa and possible damage to delicate specimens from heat or desiccation. Time required ranges from several hours to a few days.