Sugar beetle
| Sugar beetle | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Passalidae | ||||||||||||
| Leach , 1815 |
The sugar beetles (Passalidae) are a family in the order of the beetles (Coleoptera). There are 680 species in 61 genera and two subfamilies known.
features
Beetle
The beetles are 15.0 to 70.0 millimeters long. Their body has an elongated, cylindrical shape and, shortly after hatching from the pupa, is orange to deep maroon, later black in color. In some species, the ventral side is moderately dense, with yellow hairs protruding from it. The mouthparts are prominent (prognath). The head is narrower than the thorax . It often has a horn in the middle of the top. The compound eyes are divided by a clearly recognizable sclerotized bar (canthus). The forehead plate ( clypeus ) is receded and either separated from the forehead by a seam, or runs vertically and is hidden below the forehead. The upper lip ( labrum ) is well developed and is directed forward below the front edge of the head capsule. The edge of the head capsule is deeply indented, double-indented or ends abruptly. The epipharynx has a slightly sclerotized, partially double-lobed anterior part and a membranous posterior part. The antennae are ten-limbed with a three- to six-limb club. They are turned in below a conspicuous, forward-facing edge. The sensors cannot be placed next to each other, but can be rolled up. The long and curved mandibles lie below the tip of the labrum. They have a blunt, movable tooth that is directed towards the distal side of the mola. The maxillae have a slender, horizontally lying cardo and four-membered palps . The labium has a double lobed mentum and a clearly pronounced prementum .
The square pronotum is wider than the head and has a smooth surface with a central longitudinal furrow. The indentations for the coxes of the middle legs are closed. An empodium is trained.
The deck wings are elongated and have parallel side edges. Their tips are rounded. They have strong longitudinal lines. The wings (alae) have several characterizing features at the base and the wing veins . Five ventrites (visible sclerites ) can be seen on the abdomen . The stigmata on the abdomen, of which the first to seventh functional are located in the membrane of the pleura . The stigma on the eighth segment has receded. Seven sternites are formed on the abdomen. The male aedeagus is uniquely spherical and has an unusual sclerotized surface with the sides and top being membranous.
Larvae
The larvae have an almost straight body that is not or only slightly curved. The head is almost prominent (prognath). The segments on the thorax and abdomen are not divided with folds on the back. The body has long, strong pigmented bristles on the back. The frontoclypeal suture lies between the dorsal side of the mandible joint. Point eyes ( Ocelli ) are not trained. The two-part antennae are short and do not have a large area with sensory hairs. The Maxillarpalpen are without the Palpifer Dual-Segment, the latter is formed in segments, which makes it appear that the Maxillarpalpen are tripartite. With the middle pair of legs, the animals can create sounds through stridulation . The rear pair of legs is stunted to short, single-limbed appendages, which is why it appears that the larvae only have two pairs of legs. The suture between the thigh ring (trochanter) and the splints ( femora ) of the first two pairs of legs is missing.
Occurrence
The family is primarily found in the tropics, but is also found in the temperate regions of North America, South Africa, and Australia. The subfamily Passalinae occurs throughout the distribution area, the subfamily Aulacocyclinae are restricted to Southeast Asia and Australia. In the Palaearctic three species of the genus are Cylidroncaulus from Japan and China and a member of the genus Leptaulax from South Korea demonstrated. There are six known endemic species in Madagascar . In Australia the family is represented with nine genera and 34 species, in the United States there are two species of the genera Odontotaenius and Passalus .
Way of life
The sugar beetles are, unusual for beetles, state-forming . The adults live together with the larvae in feeding tunnels in rotten wood, which are created by the adults. Rotten tree trunks and stumps made of hardwood are settled. The beetles appear there in small groups with a few individuals and feed on the wood. The adults chop up wood for the larvae and mix it with their saliva. The larvae are presumably dependent on this behavior, as they cannot develop further without the presence of the adults. Both the larvae and the adults have to eat the feces of other adults in order to get to the microorganisms in them, with whose help the wood is digested.
The eggs of many species are red shortly after being laid, but after a while they first turn brown and finally green. The adults and larvae can communicate with each other through stridulation , with 14 different sounds being detected.
Systematics
The sugar beetles are divided into the following subfamilies:
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).
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).
