Dung-beetle

The dung-beetles are insects Coléoptère S coprophages. The majority of these species belong to the S of the Scarabaeinae and the Aphodiinae of the family of the Scarabaeidae . They exclusively nourish excrements, the subfamily of the Scarabaeinae is sometimes vulgarly called true dung-beetles . One finds also dung-beetles in other families, like the Geotrupidae (the beetle tunneller ). The only family of Scarabaeinae includes/understands more than 5.050 species.

Behavior

Many beetles dung-beetles, called pill machines , make use of their forefeet and their Mandibule S to work the spherical pieces of dung in pelottes which they can thus move by making it roll on the ground, using the fecal matter at the same time like food and construction material. Other dung-beetles, the tunnellers , bury the pieces of dung each time they can it. A third group, the Endocopride S , live quite simply in the dung, without moving it nor to work it. They are often specialized for Bouse S of a precise species.

Description

These beetles present a head in the shape of shovel. The tibiae of the forefeet powerful and are widened. Thanks to this morphology, they gather excrements (for example dungs of Vache), form of it a ball which they roll using their back legs and which they will consume with the shelter.

They should not be confused with the dung-beetles Geotrupes stercorarius and close species, which dig galleries in the saddles but do not form balls.

The size of the dung-beetles is variable from one species to another; the endocoprides are usually long and thin. The dung-beetle is generally of color black or brown dark; its Exosquelette offers sometimes a metallic luster, particularly at the tropical species. The majority of the dung-beetles have a flat, but robust body. The males have the head or the horned thorax. Some beetles, except for the endocoprides, are provided with powerful and toothed legs which enable them to work and to make roll the balls of excrement with a correct gripping. The tarsus S of the forefeet of an adult dung-beetle very worn or are generally mutilated because of ceaseless work of roadway drivage (certain species do not have even straightforwardly a tarsus with the forefeet). Certain species living in the desert have covered legs of Cil S which enable them to move more easily in sand. As for the mandibles, they are adapted to the food mode of this animal.

One knows of them several species in Europe of which:

Scarabaeus semipunctatus Fabricius
Scarabaeus sacer L.
Scarabaeus laticollis L.

Ecology and ethology

The dung-beetles are in extremely varied habitats: deserts, cultivated grounds, the forest, and meadows. However, they feel reluctant at the extreme temperatures. One finds them on all the continents, except in the the Antarctic.

The dung-beetles nourish themselves deposit of Herbivore S and Omnivore S, but with a preference for the first. Several of them nourish also Champignons and of Feuille S and Fruit S in Décomposition. They do not need any other food insofar as the excrements contain the totality of the nutrients which their metabolism needs. In the same way, the moisture of the excrements the exemption of drinking. The Larve S nourish vegetable fibers not completely digested by the mammals, whereas the adults cannot eat any solid food: their mandibles are used to them to compress the fecal matter and to suck the juice which is expressed some, a liquid full with micro-organisms and other food (as for example the Lymphe of some caterpillar S coprophages which finish between the mandibles of a dung-beetle!).

The dung-beetles generally find their food using their Odorat very developed. The smallest varieties, however, are restricted to cling to the thighs ruminants while waiting for their subsistence.

Researchers of the Université of Lund showed that a species of dung-beetle is directed thanks to signals polarized in light of day. But very often also, the dung-beetles seek to adapt the fecal ball of congeneric, which obliges the animal to hasten to leave a dung once it succeeded in forming a ball of good size, of fear of being made it fly. The shortest way being the straight line, the animal uses a point of aiming which it does not leave any more of the eyes to move its burden.

The species studied by these researchers, S. zambesianus , makes in theory balls 2 cm in diameter, except when a male seeks to couple itself with a female; it then will make a giant ball 5 cm in diameter. The female will go up on the ball of time to others to lay there, then the offspring will nourish this ball itself.

Function in the ecosystem

The dung-beetles play a particular part in the Agriculture: while burying or in recycling the excrements by their digestion, they accelerate the formation of natural Engrais and enrich the ground in Organic matter and Rock salt. They protect as the Bétail, in particular the Ruminant S, of the possible infections as the excrements, a long time abandoned with the natural putrefaction, could propagate via parasites as the Mouche S. For this reason of many countries introduced these creatures for the great benefit of their breeding. In the Country in the process of development, the dung-beetles are a big factor of promotion of hygiene.

The American Institute off Biological Sciences estimates that the dung-beetles, by burying the dejections, make save approximately 380 million dollars to the agro-alimentary sector of the the United States. The absence of endemic insects coprophages able to recycle the feces of animals introduced in Australia, pushed the Australian governments to acclimatize several species of dung-beetles.

The Chinese Médecine uses the dung-beetles, like many other insects, in desiccated form, like ingredient called qianglang (蜣蜋).

The beetle in the ancient Egypt

Egypt venerated several species of dung-beetles, in particular the Scarabaeus sacer .

The dung-beetle in literature

The fable of Ésope entitled “ the dung-beetle and the eagle ” tells how a keep silent eagle a hare in spite of the petitions of a beetle. The coleopter is avenged while destroying by twice eggs for the eagle. The bird, despaired, flies towards the Olympe and gives its last eggs between the hands of Zeus, requesting the sovereign of the gods to protect them. When the beetle discovers the loophole found by its adversary, it coats dung and falls down on the face of Zeus which, surprised, breakage eggs. Zeus then learns the objections from the beetle ignored by the eagle. It reprimand the eagle, then request with the beetle, but in vain, to be held from now on remotely of the bird. Also it changes the season of laying of the eagles to make it coincide at one period when the dung-beetle winters. Érasme devoted a rather long comment to this fable in its “ Adages ” (“ the beetle with the chase of the eagle ”).

Aristophane often referred to the fable of Ésope in its parts: in “Peace”, the hero gallops towards Olympe to release the goddess of Peace, but its mounting is a gigantic dung-beetle which has ingurgity of enormous quantity of excrements.

In “ the metamorphosis ” of Franz Kafka, the transmuted shape of the hero, Gregor Samsa, is described as “old dung-beetle” (“alten Mistkäfer”) by the cleaning lady.

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