Some Physical Gradients Set Up in Tullgren Funnels During the Extraction of Mites from Poultry Litter

In the present experiments, a twelve funnel version of the Tullgren apparatus (Burkard Manufacturing Company, Rickmansworth, Hertfordshire) was used to assess the freeliving mite fauna of poultry deep-litter. No relevant published information exists on the performance of this apparatus during the extraction of arthropods from either soil or litter. An attempt was therefore made to determine the physical characteristics of poultry litter during extraction in the funnels. It is hoped that the account which follows will facilitate the work of others who acquire the apparatus for the extraction of fauna from various forms of litter. In addition, some new data on physical gradients in Tullgren funnels are given.