Scarabaeoidea

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Scarabaeoidea
Wood dung beetle (Anoplotrupes stercorosus)

Wood dung beetle ( Anoplotrupes stercorosus )

Systematics
Superclass : Six-footed (Hexapoda)
Class : Insects (Insecta)
Order : Beetle (Coleoptera)
Subordination : Polyphaga
Partial order : Scarabaeiformia
Superfamily : Scarabaeoidea
Scientific name of the  partial order
Scarabaeiformia
Crowson , 1960
Scientific name of the  superfamily
Scarabaeoidea
Latreille , 1802
Male stag beetle ( Lucanus cervus )
Golden rose beetle larva ( Cetonia aurata )
Pill turner in the Karst of Croatia

The Scarabaeoidea , formerly also called Lamellicornia, are the only superfamily of the suborder Scarabaeiformia and belong to the suborder Polyphaga of the beetles (Coleoptera). The superfamily comprises around 35,000 species in 2,500 genera worldwide. Around 200 more species are discovered each year.

features

Beetle

The adults are characterized by the following features: their prothorax is strongly adapted for digging, the hips ( coxes ) are enlarged, almost always cover the thigh rings ( trochanters ) and have closed indentations, the rails ( tibia ) are usually toothed and have only one spur, the veins of the hind wings have receded, the hind wings have a strong, intrinsic mechanism for unfolding, the antennae are leaf-shaped, the coxal plates are missing on the hind legs, the sternite on the second abdominal segment is only on the side, the eighth tergite forms a real one Pygidium and is not covered by the seventh tergite and four Malpighian vessels are formed.

The group tends to recede the tracheal openings on the eighth abdominal segment and relocate the remaining openings towards the back or the abdominal side. In addition, the number of antennae is reduced, the aedeagus changes from a triple to a double lobe, and the male genitals change from a genital capsule to a gastric spiculum.

Pre-imaginal stages

The body of the larvae has the typical shape of a grub and is curved in a C-shape in almost all species. Only in the sugar beetles are the larvae almost straight. The body is creamy white or yellow in color. The light to dark brown head capsule is heavily sclerotized . The thorax and the first six abdominal segments are divided into two to four folds on the back and sides. Only in the sugar beetles and scrapers (Lucanidae) are the segments not folded. On the meso- and metathorax, as well as on the abdomen, there are no demarcated sclerites; these are only found on the prothorax. The body surface is either covered with only a few hairs, almost completely smooth, or, as in the Glaphyridae, very hairy. The segments on the thorax and abdomen are never flattened dorsoventrally. The legs are well developed. Some species have sound-producing organs on the front and middle pairs of legs ( Hybosoridae and some Ceratocanthidae ) or on the middle and rear pairs of legs (Schröter, sugar beetles, Pleocomidae, some dung beetles (Geotrupidae) and Bolboceratidae ). Occasionally, the hind legs of some dung beetles are partially reduced and that of the sugar beetles strongly receded. As a rule, a single claw is formed on the pretarsus, which is missing in some species of the Bolboceratidae and the Scarabaeinae . The claws have two, four or more bristles or are not bristled. The Urogomphi on the ninth tergum are always absent. The tracheal openings on the mesothorax are relocated to the anterior part of the prothorax, those of the metathorax are normally located on the mesothorax, are significantly reduced and inoperable.

The larvae usually have no ocelli , only the earth beetles (Trogidae) and some scarab beetles (Scarabaeidae) have one. The head capsule has a clearly visible epicranial suture, the frontoclypeal suture is only missing in dung beetles, Bolboceratidae and some species of earth beetles and Ceratocanthidae . The antennae are four-parted and usually of the same length as the mandibles . In the dung beetles, Bolboceratidae, Erdbeetle and Pleocomidae they are tripartite, in the sugar beetles they are bipartite. The feelers are attached to the head capsule on the clearly formed antennae . The mandibles usually do not have a retinaculum but have a well-developed mola. They are usually asymmetrical. The basal part of the maxilla (stipes) mostly has hairs dorsally for stridulation. The galea is not structured and is firmly connected to the stipes. In some species it is fused with the Lacinia . The labial palps are two-limbed, only in some Ceratocanthidae and scarab beetles are they one-limbed. The tip of the labrum differs, but it is always clearly separated from the head capsule. The epipharynx has a complex structure, the hypopharynx has noticeable bristles.

In the larvae a change towards a loss of the closing mechanism of the trachea can be seen, as well as the development of sound-producing organs in different areas of the legs, the increase in the number of antennae elements from three to four and the fusing of the galea and lacinia.

The pupae of the Scarabaeoidea only have functional tracheal openings from the first to fourth abdominal segment.

Way of life

The species of the Scarabaeoidea feed on a multitude of different plant and animal substances, with the adults often living in the same places and eating the same things as the larvae. For example, the Pleocomidae and some Scarabaeidae feed on roots, the Schröter and sugar beetles live in them and feed on detritus and deadwood, the Bolboceratidae and Geotrupinae feed on mushrooms that grow underground, the Ceratocanthidae on tree fungi, the Aphodiinae and Scarabaeinae from the family dung beetles and scarab beetles eat dung from herbivores, the Pleocomidae, Melolonthinae, Dynastinae and Rutelinae eat the roots of living plants, some groups eat humus, the earth beetles eat carrion. Species of the Ceratocanthidae, Aphodiinae, Valginae and rose beetles are associated with social insects . However, there are also species, such as those of the Pleocomidae, Diphyllostomatidae and some species of the Melolonthinae, Dynastinae and Rutelinae, which as adults do not eat at all. Deviating from the classical way of life described so far, some species of the Melolonthinae, Rutelinae and rose beetles eat leaves, flowers and fruits and some Scarabaeinae, Hybosoridae and rose beetles hunt predatory smaller creatures.

Both the larvae and the adults are adapted to digging in the ground. A number of groups have more or less pronounced social behavior and fairly well developed forms of brood care . Especially with the dung beetles and Scarabaeinae, the adults dig burrows for their larvae. In the sugar beetles, a simple form of social behavior has even developed, in which the adults live together with the larvae, which they care for and feed together. They also help the larvae with pupation.

Taxonomy, systematics and tribal history

The oldest known fossil record of the group dates back to about 200 million years ago and is attributed to the genus Aphodiites , which has a strong resemblance to the recent genus Glaresis . However, it is assumed that the development of the Scarabaeoidea began as early as the early Mesozoic . Fossil finds show that the basal clade of the group was already well developed in the Upper Jurassic and Lower Cretaceous . It is believed that these basal species were mycetophagus , that is, they fed on fungi.

The superfamily Scarabaeoidea probably has a sister relationship with the Dascilloidea or various groups of the Staphyliniformia . According to Beutel / Leschen (2005), it now includes 14 families. By far the largest of which are the scarab beetles (Scarabaeidae) that after the currently prevailing view among other Aphodiinae (including Aegialiinae and Aulonocneminae) that Phaenomeridinae that Scarabaeinae that Orphninae that melolonthinae , the species Acoma that Rutelinae , the giant beetle (Dynastinae), which includes rose beetles (Cetoniinae) and the Valginae . The following is a list of families:

supporting documents

Individual evidence

  1. ↑ a b c d e f g h i j k Rolf G. Beutel, Richard AB Leschen: Handbuch der Zoologie - Coleoptera, Beetles, Volume 1: Morphology and Systematics (Archostemata, Adephaga, Myxophaga, Polyphaga partim) . 1st edition. de Gruyter , 2005, ISBN 3-11-017130-9 , p. 345 ff . (English).
  2. ^ Brett C. Ratcliffe: A checklist of the Scarabaeoidea (Coleoptera) of Panama . In: Zootaxa . No. 32, 2002, pp. 1-48.

literature

  • Rolf G. Beutel, Richard AB Leschen: Handbuch der Zoologie - Coleoptera, Beetles, Volume 1: Morphology and Systematics (Archostemata, Adephaga, Myxophaga, Polyphaga partim) . 1st edition. de Gruyter , 2005, ISBN 3-11-017130-9 (English).

Web links

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