Whirligig beetles

Total biomass of fresh-water animals is formed mostly by molluscs, aquatic insects (larvae), bark beetles and fish. Less important from the aspect of weight, but often ecologically significant are the Annelida, whirligig beetles, and other worms [1, 2]. 

Epineuston is on the surface and includes Gerris lacustris L., many whirligig-beetles (Rotatoria) and spring-tails (Colembola). 

Soil fauna consists of a significant amount of animals of different size which are present in soil, some permanently, some temporarily. Some of them are of microscopic size, for example, protozoa which are discussed in detail within the framework of microorganisms. Microfauna covers also some metazoa, such as whirligig beetles or small worms. Macrofauna is represented by a rich groups of larger animals which are usually classified into arthropods and other animals. The greatest attention is focused on the components of fauna which occur in the arable land since they significantly influence its fertility and other properties. The main varieties are now discussed in turn. 

Whirligig beetles (Rotatoria) — microscopically small worms present in high amounts particularly in soils with high reserves of organic matter. About 100 species of them have been described, but their importance in the soil is not well known. They require adequate soil moisture and move in a thin layer of water in soil pores, but some can live in a dry environment. Their food consists of soil humus, detritus, bacteria, algae, protozoa and small nematodes. 

Gyrinidal and gyrinidone are compounds from the defensive glands of whirligig water beetles Gyrinus sp.). Suggest schemes for their biosynthesis from farnesol. Note the resemblance to iridoids. 

---