Gonioctena variabilis
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Gonioctena variabilis |
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| ( Olivier , 1790) |
 
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| Fig. 2: side view |
   
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| Fig. 3: further color variants |
Gonioctena (Spartoxena) variabilis , formerly Phytodecta variabilis , is a beetle fromthe leaf beetle family and the subfamily Chrysomelinae . Gonioctena variabilis belongs to the subgenus Spartoxena . This sub- genus of the species-rich genus Phytodecta is represented in Europe with five species .
The generic name Gonioctena is derived from ancient Greek γονία gonía , German 'corner' and κτείς, κτενός ktēīs, ktenós , German 'comb' and refers to the tooth on the central and rear rails . The name of the subgenus Spartoxena is derived from ancient Greek σπάρτος spártos , German ' Pfriemenginster ' and ξένε xéne , German 'Gastfreundin' and means that the Priemenginster is the host plant of the species. The species name variabilis from Latin variábilis, e 'different' refers to the different body color and markings of the individuals (Fig. 3).
Characteristics of the beetle
The beetle has the round to elongated and arched shape that is typical of the majority of leaf beetles. The numerous color variants overlap with those of other leaf beetles. The height of five to seven millimeters is also not very meaningful. A certain restriction is given by the forage plant and the distribution area, which is limited to the western Mediterranean region. A genital examination is recommended for a reliable determination .
The head is sloping downwards. The moderately curved eyes are on the sides of the head. The eleven-part antennae are positioned far apart from one another in front of the eyes. They do not reach the rear edge of the pronotum. The last six links are few, but increasingly inwardly expanded.
The indistinctly punctured pronotum is more arched in cross section than the elytra. On the sides it is only clearly rounded in front of the front corners. The rear corners are a little more than 90 ° and pulled back little or not at all. The pronotum can be largely black with yellowish-white spots that extend more or less far from the front corners laterally to the rear. However, it can also be completely pale yellow with the exception of a round black spot on the right and left near the base of the pronotum.
The elytra are clearly dotted, but the dots are only partially arranged in rows. The basic color of the wing covers ranges from bright red to orange and yellow to a greenish gray. It is interrupted by a different number of black, rounded or angular spots or stripes. If there are no black spots, the underside of the abdomen is also colorless. The color and drawing is controlled by several alleles .
The splints of the two rear pairs of legs have a sharp, spur-shaped tooth in front of the tip, which is missing from the anterior splint (Fig. 2). The Tarsen like leaf beetles appear customary four members (kryptopentamer), the visible Tarsenglieder wide.
For the determination of the females with the help of the sexual apparatus, the following results are obtained from the seven other species of the subgenus: The back plate of the eighth abdominal segment narrows evenly towards the rear, it is not constricted at the rear. The two halves of this back plate are widely separated at the base. The abdominal plate of the same abdominal segment is notched sharply and deeply in the middle at the rear edge. The vaginal buttons are less than four times as long as they are wide.
larva
The yellow-brown, only slightly domed larva is similar to a caterpillar. In the last stage, the larva is between 8.0 and 9.5 millimeters in length. The head is badly sclerotized and the mouthparts point down. The short antennae are tripartite. The lowest antennae is much wider than it is long, the middle one about the same length as it is wide, and the third narrow and conical. There are three point eyes on each side of the head, one below the feeler deflection and two behind the deflection. The upper lip is cut out in a V-shape at the front. To the right and left of the cutout, there are six to seven inwardly inclined, strong, short bristles on the front edge. The back corners are very slightly drawn back. On each side there are two bristle hairs and a sensory point. The symmetrical upper jaws are five-toothed and have two bristles on the outside.
The three pairs of legs are the same length. The tooth on the underside of the claw is vanishingly small in contrast to the remaining species of the subgenus.
The chest and abdomen are covered with wart-shaped elevations (tubercles). Several hair bristles emerge from each of these. The number and structure of these tubercles distinguish the species from similar species. On the back of the first breast section, the tubercles are fused to form a back plate, also on the eighth and ninth abdominal segments. On abdominal segments one to six there are four dorsal and two dorsolateral tubercles, as well as additional tubercles on the side. On the seventh abdominal segment, two laterally adjacent tubercles have grown together to form a total of two consecutive plates. The parasternal tubercle of the first abdominal segment, located under the lateral tubercle (pleural tubercle), is greatly reduced and only has two bristle hairs.
biology
The species lives oligophagous on a few types of gorse and is bound to their locations in warm, dry areas.
Role in the history of genetics
In 1925, the Spaniard Antonio de Zuleta succeeded in crossing attempts with different color variants of Gonioctena variabilis to prove for the first time that non-recessive hereditary factors can also be inherited on the y chromosome.
distribution
The occurrence of the species is limited to southern France and eastern Spain. Thus it lies within the range of the host plant Genista scorpius .
literature
- Heinz joy, Karl Wilhelm Harde, Gustav Adolf Lohse (ed.): The beetles of Central Europe . tape 9 . Cerambycidae Chrysomelidae . Spektrum Akademischer Verlag, Munich 1999, ISBN 3-8274-0683-8 (first edition: Goecke & Evers, Krefeld 1966).
Individual evidence
- ↑ a b Gonioctena variabilis in Fauna Europaea. Retrieved February 18, 2012
- ↑ Spartoxena (subgenus) in Fauna Europaea. Retrieved February 18, 2012
- ↑ Sigmund Schenkling: Explanation of the scientific beetle names.
- ↑ L. Donoaster: "On the Color-Variation of the beetle Gonioctena variabilis " Original: Proceedings of the Zoological Society of London Vol. 75, Issue 4, pp. 528-550, April 1905, reprint: Journal of Zoology, 6. July 2010 doi : 10.1111 / j.1469-7998.1906.tb08404.x .
- ↑ a b Susana Pinar: La introduccion de la genética en España durante el primer tércio del siglo XX Llull, Revista de la Sociedad Española de Historia de las Ciencias y de las Técnicas, ISSN 0210-8615 vol. 22, N ° 44, 1999, 453-473 to be opened here as full text
- ^ Andrés Baselga: "The female genitalia of Gonioctena , subgenus Spartoxena (Coleoptera: Chrysomelidae)" Journal of Natural History, 2007; 41 (37-40): 2411–2418 as PDF ( memento of the original from January 1, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ^ A b Andrés Baselga: "The mature larva of Gonioctena variabilis Olivier 1790 (Coleoptera, Chrysomelidae, Chrysomelinae) and key to the larvae of subgenus Spartoxena " ZooKeys 33: 19-27 (2010) doi : 10.3897 / zookeys.33.333 as PDF ( Page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.
- ↑ Klaus Koch : The beetles of Central Europe . Ed .: Heinz Freude . tape 3 : ecology . Goecke & Evers, Krefeld 1992, ISBN 3-87263-042-3 .
