A new method of extracting free-living arthropods and molluscs from rough, matted grassland has been developed which gives extraction rates that are usually above 95 per cent. Its advantages over other known methods, especially sweeping, are that it is less liable to personal error, collects from otherwise inaccessible places in the habitat, permits selection of places within the habitat (e.g., tops and bases of grass) and does not depend on removal of parts of the habitat.
The apparatus consists of a light, portable but powerful electric suction pump of standard pattern, with a special compartment, containing a small collecting bag, fitted between the fan intake and the flexible hose that carries a nozzle 1 in. in diameter, which is inserted into the grass. It can be operated on several hundred yards of cable.
The sample obtained comprises a mass of plant matter and detritus from which the animals are easily sorted by hand in the laboratory.
The method is unsuitable for subterranean arthropods or for insects living inside or otherwise firmly attached to plants. But it should be possible to use it for a variety of habitats other than grassland.