Giant beetle
| Giant beetle | ||||||||||||
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Rhinoceros beetle ( Oryctes nasicornis ), male |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Dynastinae | ||||||||||||
| Macleay , 1819 |
The giant beetles (Dynastinae) are a subfamily of the scarab beetles (Scarabaeidae). About 1500 species in 225 genera and 8 tribes are known. The group is distributed worldwide, but is most species-rich in the tropics. The giant beetles include some of the largest insects in the world, such as the Hercules beetle ( Dynastes hercules ) with a body length of up to 225 millimeters. The genus Megasoma also includes species that are among the heaviest insects in the world.
features
Beetle
The beetles have a body length of 10 to 225 millimeters. Their body is usually reddish brown, brown or black in color. Males and females mostly differ from one another ( sexual dimorphism ); Males have either horns or enlarged tubercles or enlarged tarsi on their front legs. There is no sexual dimorphism in the Phileurini and some Cyclocephalini and Pentodontini . The antennae of the beetle are nine or ten-membered, the three-membered antenna lobe is usually small. On pronotum (front chest) and head horns are formed in the males of some species. The compound eyes are divided into two parts. The front edge of the frontal plate ( clypeus ) is either rounded, double-toothed, tapered to a point or short blunt. The front plate covers the labrum (upper lip). The mandibles are designed differently. In the Cyclocephalini and some species of the Phileurini the teeth are missing on the sides, in the other species there are teeth or tips.
The scutellum is normal and never enlarged. The coxae of the front legs are transverse, the tibia of the middle legs have two spurs at the tip, which are directed towards the middle, adjoin each other and are not separated from the basal tarsal phalanx . The claw members of the tarsi are all about the same size, except in the males of most Cyclocephalini species and some species of Pentodontini, where the claws on the front legs are enlarged. An empodium is always developed on the tarsi. The spiracles on the metathorax are modified. The wings are designed like the beetles of the subfamily Rutelinae . The wing field 1Ax has a strongly receding distal arch at its end, the wing tip is broadly rounded, 3Ax has a convex tip, in 2BP the front and rear areas of the branches of BMP-BcuA are widened at the front and the front indentation of BcuA is deep.
The spiracles on abdominal segments one through seven are functional. Those of the segments one and two or one to three or one to four lie in the membrane of the pleura , those of the segments three to six, four to six or five to six lie on the sternites . The stigma of the seventh abdomen segment lies between the sternite and the tergite .
Larvae
In the larvae, the two chews, the galea and the lacinia, have grown together to form the mala . The mandibles have an area on the underside with which the animals can stridulate .
Way of life
The adults feed on tubers, grains or flowers. The larvae mainly eat roots and humus. Some species also develop as bores in plants, such as palm trees . A number of species can cause damage to lawns , young forest plants and in agriculture to root vegetables . In Africa, species of giant beetles are known to feed on the brood and food supplies of honeybees .
Systematics
The Dynastinae belong to a herbivorous clade of scarab beetles, which also includes the Melolonthinae , Rutelinae, Cetoniinae and Valginae . Phylogenetically , however, there are difficulties in demarcating the Dynastinae and the Rutelinae. The following tribes are counted among the Dynastinae:
- Tribe Pentodontini
- Tribe Oryctini
- Tribe Phileurini
- Agaocephalini tribe
- Tribe Dynastini
- Tribe Hexodontini
- Tribe Oryctoderini
- Tribe Cyclocephalini
Types (selection)
- Hercules beetle ( Dynastes hercules )
- Rhinoceros beetle ( Oryctes nasicornis )
- Pentodon idiota
- Atlas beetle ( Chalcosoma atlas )
supporting documents
Individual evidence
- ↑ a b c d e f g 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).
