A Berlese funnel, also known as Tullgren funnel, Berlese trap, or Berlese-Tullgren funnel, is an apparatus used to extract living organisms, particularly

arthropods Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a Segmentation (biology), segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and Arth ...

, from samples of

soil Soil, also commonly referred to as earth or dirt, is a mixture of organic matter, minerals, gases, liquids, and organisms that together support life. Some scientific definitions distinguish ''dirt'' from ''soil'' by restricting the former te ...

. The Tullgren funnel works by creating a

desiccation Desiccation () is the state of extreme dryness, or the process of extreme drying. A desiccant is a hygroscopic (attracts and holds water) substance that induces or sustains such a state in its local vicinity in a moderately sealed container. ...

gradient over the sample such that mobile organisms will move away from the dry environment and fall into a collecting vessel, where they perish and are preserved for examination. The illustration shows how it works: a funnel (E) contains the soil or litter (D), and a heat source (F) such as an

electric lamp An electric light, lamp, or light bulb is an electrical component that produces light. It is the most common form of artificial lighting. Lamps usually have a base made of ceramic, metal, glass, or plastic, which secures the lamp in the soc ...

(G) heats the litter. Animals escaping from the desiccation of the litter descend through a filter (C) into a preservative liquid (A) in a receptacle (B). This illustration is merely a schematic, since usually the soil sample will not be crumbled and poured into the funnel (this would inevitably lead to a high amount of soil particles in the preservation fluid requiring laborious work to sort out the

soil organisms Soil biology is the study of microbial and faunal activity and ecology in soil. Soil life, soil biota, soil fauna, or edaphon is a collective term that encompasses all organisms that spend a significant portion of their life cycle within a soil ...

). In fact, the soil sample is placed on a mesh sieve that will allow the soil animals to pass but should retain most of the soil particles. This type of extraction is commonly referred to as Berlese funnel or Tullgren funnel. Antonio Berlese described this method of dynamic sampling in 1905 with a hot water jacket as heat source. In 1918 Albert Tullgren described a modification, where the heating came from above by an electric bulb and the heat gradient was increased by an iron sheet drum around the soil sample. Today's extraction funnels of this type usually combine elements from both publications and thus should be referred to as Berlese-Tullgren funnel. A variation of the Berlese funnel uses

naphthalene Naphthalene is an organic compound with formula . It is the simplest polycyclic aromatic hydrocarbon, and is a white crystalline solid with a characteristic odor that is detectable at concentrations as low as 0.08 ppm by mass. As an aromati ...

flakes or similar aromatic mothballs in place of the heat source to drive organisms downward. This method finds application in situations without electrical power, where the organisms are repulsed by volatile preservatives in collection container, or they cannot migrate downward quickly enough to avoid desiccation.

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