Tullgren funnel

All Sources -
Updated Media sources (1) About encyclopedia.com content Print Topic Share Topic
views updated

Tullgren funnel A device used to remove and collect small animals, such as insects, from a sample of soil or leaf litter. The sample is placed on a coarse sieve fixed across the wide end of a funnel and a 100-watt light bulb, in a metal reflector, is placed about 25 cm above the funnel. The heat from the bulb dries and warms the sample, causing the animals to move downwards and fall through the sieve into the funnel, which directs them into a collecting dish or tube below. The dish can contain water or alcohol to prevent the animals from escaping.

views updated

Tullgren funnel A device used to extract small invertebrate animals from a dry soil sample. The sample is placed in a container with a base made from gauze, with a mesh designed to hold soil particles but permit the animals to pass. The container is arranged over a funnel, with a light above. The heat causes the animals to move away from the top of the sample, through the gauze sheet and into the funnel from which they can be collected. Most species are collected after two hours, but complete extraction takes 2–3 days.

views updated

Tullgren funnel A device used to extract small invertebrate animals from a dry soil sample. The sample is placed in a container with a base made from gauze with a mesh designed to hold soil particles but permit the animals to pass. The container is arranged over a funnel, with a light above. The heat causes the animals to move away from the top of the sample, through the gauze sheet and into the funnel from which they can be collected. Most species are collected after two hours, but complete extraction takes two-three days.