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Stag Beetles (Lucanidae)

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This key is based on the identification tables of the genera and species of the Lucanidae family (Medvedev, 1965, Nikolaev, 1989), and is an application that should facilitate the identification of species of stag beetles for novice amateurs, as it is built according to the type of pictorial determinants and contains visual illustrations for each thesis. It is worth noting that this identifier was developed directly for the Saratov region, but can also be used for many regions of the European part of Russia, since the stag fauna is similar for most European regions

Stag beetles are easily distinguishable among other taxa of the order; their determination is not difficult. Two species of stag beetles are rare in the Saratov region: it is Lucanus cervus (L., 1758), listed in the Red Book of the Saratov Region (1996) and in the Red Book of the Russian Federation (2001) (category 2 is a declining species), and Sinodendron cylindricum (L., 1758) - a species that needs special attention. The causes of the deterioration of the populations of these species are directly or indirectly associated with anthropogenic and abiotic factors. The larvae of stag beetles in their development are closely related to old and dead trees and shrubs, therefore, the conservation factor of old and unchanged primary biotopes should be taken into account, which undoubtedly contributes to the stabilization of the number of species of this family. Currently, the fauna of stag beetles in Russia is represented by 18 species (2005), 7 species were cited for the European part of the USSR (1965). In the territory of the Saratov region, the authors currently note 4 species of Lucanidae (Sakharov, 1903-04, Sazhnev, Rodnev, 2005).

Family Lucanidae Latreille, 1806

Medium to very large beetles (5.0 - 70.0 mm). Mandibles are strong, more developed in males than in females, sometimes (in Lucanus) reach a huge size. Antennae are cranked, with long stems and a 3-6-segmented comb club, or simple. Abdomen with 5 visible sternites. Middle coxae markedly divided, tarsi 5-segmented, claw segment with small empody, bearing 2 setae. Beetles feed on sap flowing from wounds of deciduous tree trunks. Larvae develop in rotting wood, long-term generation (up to 6 years). Up to 800 species, most in the tropics.

Stag habitats

Representatives of the Lucanidae family are most numerous in the forest regions of the tropics, also found in the subtropics and in temperate regions. Only two dozen species from a large stag family live in Russia.

For the emergence of a colony of beetles, it is necessary that there are enough stumps and felled trunks in the forest. This is explained by the fact that the larval stage of stag beetles almost entirely occurs in old trunks and stumps. Until the end, it is not known what specific tree species prefer stag beetle. Larvae are often found next to old stumps of oaks, cork oaks, as well as palm trees and other tropical trees. One of the factors that really matters is the age of the trunks or stumps. Stag beetles prefer wood at the stage of deep decomposition, although each species of beetles from the Lucanidae family has its own preferences. For example, a stag beetle (Lucanus cervus) develops mainly in trunks with a diameter of more than 20 cm or stumps of trees that died at least five years ago.

Species of stag beetles

About 1,500 species of Lucanidae are known that are distributed around the world. Below are some of them.

Stag Beetle (Lucanus cervus)

One of the largest beetles: males of this species reach a length of 10 cm. It lives in the south of the forest zone and in the forest-steppe, preferring oak forests of the European part. The males are equipped with very developed jaws that gave the name to this genus.

Lucanus cervus

Giant stag beetle (Lucanus elaphus)

In terms of its external structure, it is very similar to a stag beetle, but surpasses it in size, reaching 12 cm. It also has a lighter brownish color. Lives in the old forests of North America, but because of their intense deforestation, its population is gradually declining.

Lucanus elaphus

Wingless stag from the island of Kauai (Apterocuclus honoluluensis)

This relatively small representative of the family lives only on the island of Kauai, Hawaiian archipelago. It differs from other representatives of the family by fused elytra. Under the wings, this species has a pair of underdeveloped wings, but since the elytra do not rise, it cannot fly.

Apterocuclus honoluluensis

Beetle Titan (Dorcus titanus)

The length of the males of this species exceeds 10 cm. The head of large representatives is equal in size to the body. It lives in tropical forests and prefers trunks of deciduous trees with solid wood.

Chinese stag beetle (Dorcus hopei)

It lives in oak forests. The beetle larva develops in oak trunks from a year to two years. Adult individuals appearing in the summer live up to 3-4 years. There are 2 different subspecies that differ in the degree of development of the jaws in males.

Dorcus hopei

Rainbow Stag Beetle (Phalacrognathus muelleri)

Males grow up to 7 cm in length. The rainbow stag beetle lives in the Australian forests, developing in the fallen trunks of cedars. Active at night and flies to the light. It is well bred at home.

Phalacrognathus muelleri

North African Stag Beetle (Pseudolucanus barbarossa)

This species is endemic to the Iberian Peninsula and North Africa. Compared to a stag beetle, this beetle is small. Favorite habitats are oak groves.

Pseudolucanus barbarossa

Individual representatives of the genus are very beautiful. Due to the color contrast between the abdomen, head and chest, these species are popular with collectors.

The body structure of stag beetles

Most species of stag beetles are large in size: the length of the males can exceed 12 cm, of which a significant part falls on the powerful jaws resembling horns in shape. However, there are species with small jaws typical of other families of beetles.

Stag beetles have a strong build: an elongated body is combined with a large head. In some species, the head and pronotum (pronotum) may exceed the width of the abdomen. The impressive size of these departments is also explained by the fact that powerful muscles are located inside them, which move the huge jaws.

Head

The head of these beetles is wide and powerful. On it are small eyes, antennae and mouth organs. The back of the head is firmly articulated with the shield of the chest, so its mobility is very limited. Such a strong joint is necessary for the insect during fights with an opponent.

Eyes

Relatively small faceted eyes are hidden behind the antennae and jaws on both sides of the head. Formed by a large number of ommatidia.

Antennae

The antennae of the beetles are articulate, with a long first segment and a 3-6-segmented mace, consisting of movable plates. In a dense mace, these plates are folded at rest. Antennae are sensory organs giving the insect various information about the world around it.

Jaws

In males of this family, the jaws are very strongly developed. But they do not use them for food, but for fights with rivals in the mating season.

Nadkralya

From the back, the abdomen is covered by elytra - they lost their original flight function and turned into plates protecting the abdomen and wings of the second pair (the wings themselves). Elytra strongly chitinized, characterized by considerable thickness and hardness. The color of the elytra and the pattern on them, formed by dots and shading, vary in different species. Each species has an individual pattern that makes it easy to identify these beetles.

Second pair of wings

The wings of the second pair are used for flight. They are represented by a transparent membrane penetrated by a network of veins that strengthen the wing and become its mechanical support. At rest, the wings retract under the elytra.

The stag legs are quite long and consist of segments. The last leg segment is called the tarsus, or tareus, and is formed by five segments. On the last segment of the paw there is a pair of claws and a small empody (membranous plate between the claws) with two setae. With the help of claws, stag beetles are held on the branches of plants.

Palps

The so-called palps of the lower jaws. These jointed appendages are supplied with a large number of sensitive hairs and perceive various irritations (taste, smell, etc.).

Sexual dimorphism

For stag beetles, pronounced sexual dimorphism is characteristic: males differ from females not only in large size, but also in powerful jaws resembling deer horns. In females, the jaw is much more modest than in males.

According to research, males and females behave differently. Both of them, for example, have wings suitable for flights, but males mainly fly into the air, while females always remain close to the breeding places.

Stag beetle lifestyle

Most often, representatives of the stag family can be seen at the stage of an adult (adult), and most of the life of these insects passes unnoticed for us. The long larval period of stag beetle is carried out in rotten trunks and stumps. The life of adults is usually short - from 15 days to a month, but there are also species that live for several years.

Larval stage

Larvae hatch from eggs 2-4 weeks after the female lays eggs in the ground near a decaying rotten stump. Hatched larvae move underground under the stump and penetrate inside, gnawing galleries in it. There they grow and molt. Larvae of the last age equip doll cradles of wood, earth and saliva, in which they turn into pupae. After a certain time, adult insects appear from the pupae.

Rotting bark and wood are not very nutritious and are difficult to digest, so it takes a long time for the larvae to fully develop and turn into adult beetles.

Stag beetles are insects with the longest larval stage. Of course, they are far from some cicadas, but still this stage from the time of laying eggs to the appearance of adults can last up to 7 years. Those. the larval stage in stag beetles is much longer than adulthood, which in many species does not exceed several weeks. During this short period of time, usually coinciding in the temperate zones with the summer months, adults should fulfill the only task: to find a mate and mate, to give rise to a new generation.

A long larval period often leads to the fact that in many places the number of adults varies sharply from year to year. This phenomenon is cyclical in nature and depends both on the natural conditions prevailing during the larval stage of the development of beetles and on the number of adults at the time of laying eggs by females.

Mating season

When adult bugs finally leave their shelter and surface, the most interesting period in the life of these amazing insects begins. Females secrete pheromones - substances that spread through the air and attract males, catching them with the help of special senses located on the antennae. Since males are able to capture the smell of a female from a great distance, they flock to her from all around.

At this time, bright males can be seen flying back and forth near the trees. Due to the large size, loud buzzing and open elytra, it is difficult not to notice them.

Because of the female, males arrange spectacular, but not very fierce fights - stag beetles are not too aggressive. Powerful jaws play a major role, but their task is not to hurt an opponent. The meaning of the fight is to throw a competitor off the branch. Before the fight, the males rise high on their front and middle legs, standing up on their hind legs and opening their jaws wide, taking the most advantageous position for attack. Then they rush at each other. The techniques used by bugs are very similar to the elements of freestyle wrestling. It is necessary to raise the enemy into the air and drop it to the ground.

With the help of the jaws, the stronger opponent grabs the weaker by the body, lifts it and throws it with the exact movement from the branch on which the duel unfolds. Opponents often mutilate each other, and yet the defeated survives. The winner goes to the female. The triumphant approaches her and performs the courtship ritual. The female retains immobility during this, and the male holds her with front and middle legs and jaws.

Hypertrophied jaws serve as an excellent example of how qualities are selected in the process of evolution that give their owners significant advantages. if the jaws retained their original purpose and were provided with sharp ends adapted for chopping food, fights between males would end in the death of one of them. The death of males would be dangerous for the species as a whole, especially if we take into account the long larval stage and the slow growth of the stag population, due to their low fecundity. Evolution contributed to the development in males of very large and poorly functional jaws, suitable only to capture the enemy, without causing him serious harm. Along with the development of jaws, body size and overall insect strength increased. The strongest and largest males win the fights. It is not surprising that in the future their offspring with powerful jaws has the maximum advantage over individuals whose jaws are not sufficiently developed.

Stag food

Adult stag beetles practically do not eat - their body has a sufficient supply of nutrients accumulated during the larval stage. Therefore, they do not need to waste time searching for food - they can fully concentrate on reproductive function. Sometimes, however, adults gather at the damaged bark of the tree through which the juice oozes. In some species, females are able to make holes in the bark of trees with the help of mandibles to get to the sap.

At home, stag fed with an aqueous solution of honey or sugar syrup.

Briefly about captive stag breeding

To help the natural restoration of the population of some members of the family in nature, people create special places for them, providing them with food and suitable conditions for growth. The disappearance of old forests leads to a rapid decline in the population. A man is trying to fix the situation with the help of artificial pyramids of oak trunks driven into the ground. Such pyramids are placed in the habitats of stag beetles, creating favorable conditions for laying eggs by females.

Successful breeding of stag beetles at home requires patience and knowledge of the biology of these insects. The work ahead is long and hard. It should be borne in mind that the larval stage in some species of this family lasts up to seven years, so the efforts made by the breeder will not immediately pay off. For the normal growth of beetles, it is necessary to provide them with enough food and maintain the necessary temperature and humidity. But a lot of space is not needed, since the larvae move in space only in search of food. It is enough to take several containers from any material that allows you to control the growth conditions and fill them with a substrate (usually sawdust of different tree species). Constant monitoring of conditions in the cage will help to avoid egg damage by the mycelium of the fungus. In 5-6 years after laying the eggs by the female, you will receive magnificent adult individuals!

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