GB No. 4(23)/96
Everybody knows what beetles (Coleoptera) look like. You have probably seen a ladybug, a Colorado beetle, a dung beetle, a cockchager or a black Carabus running among fallen leaves. The presence of the hard integuments which cover the wings is the common and easily observable feature of these insects. These integuments are a modification of the first pair of wings.
However, few people know that the most numerous family of beetles in Poland is represented by Staphylinidae. To date, about 1200 species of these insects were observed in our country (17% of all Coleoptera in Poland). Over 20000 species of Staphylinidae live all over the world.
How can you recognize a representative of this family? Although they can take different sizes (about 1-40 mm) they all have an elongated and flattened body. Shortened integuments characterize the best. They cover only the two first segments of the abdomen. The whole body often glitters metallically. The integuments of some of the species have red, greenish of bluish color. Staphylinidae have strong legs and run quickly.
Most of these beetles, when threatened, put up the back part of the abdomen. This makes these small creatures similar to scorpions! Some of them (Staphylinus olens) spurt out an irritant liquid when attacked. All the species from the Paederus genus contain poisonous substances which acts like perite. If you squeeze the beetle and your skin is irritated by this liquid, it may cause blisters which are difficult to heal. As the most poisonous species, Paederus has a vivid, frightening color. It seems to inform "leave me alone!".
Staphylinidae are not easy to observe since the habitat of most of them is the litter in the forest, or the organic remains. Some of them hide under the bark of a tree (e.g. Nudobius lentus which feeds on borers), in nests and burrows of different animal and in anthills. Most of Staphylinidae which have adapted themselves to life in anthills belong to the family Aleochrinae. Such beetles are usually hated by ants because they eat the eggs, larvae and pupas of ants. In addition, Staphylinidae defend themselves against attacks of their hosts by secreting frightening substances from different parts of their abdomen. However, some of the Staphylinidae which live in the anthills behave differently. Instead of frightening liquids, they secrete a liquid which is a delicacy for ants. In this way they pay them for "renting the flats". Ants don't fight with such beetles and also take care of them and feed them.
Staphylinidae dwell in different habitats. They can be met almost everywhere in Poland - from the Baltic coast to the peaks of the Tatra Mountains! The species from the genus Philonthus are one ofthe easiest to observe.
The representatives of the genus Stenus and Paederus hide on the wet banks of rivers and reservoirs.
Almost all of Staphylinidae are predators. They feed on insects' larvae and also on other small invertebrates. They are useful in the biological fight with the pests. They play a huge role in the fight with the borers.
Some of them feed on resolving organic matter and also plant food (e.g. Anthobium torquatum which eats pollen).
I would like to encourage you to pay attention to observing the litter during walks through the forest. It is quite probable that you will notice one of the Staphylinidae running quickly, glittering and putting up his abdomen...
Ewa Olejnik
reprinted from "Salamandra" bulletin II/1995(3),
by The Polish Society for Nature Protection