What is tullgren funnel?

Tullgren funnel is a commonly used device in entomology for collecting small arthropods from soil and leaf litter. It consists of a metal frame with a cone-shaped funnel at the top and a mesh bag at the bottom. A heat source (such as a bulb or lamp) is positioned above the funnel, which forces the insects and other arthropods to move downward toward the bottom. The mesh bag at the bottom collects the specimens, which can be easily removed and examined. Tullgren funnel is particularly useful for extracting small and delicate arthropods, such as mites, springtails, and beetle larvae, that may be difficult to capture using other methods. It is a non-destructive method of collecting specimens that allows for further study and research.