Chlaenius velutinus
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Chlaenius velutinus |
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| ( Duftschmid , 1812) |
Chlaenius velutinus is a beetle from the family of ground beetles and the subfamily Chlaeniinae .
The genus name Chlaenius is from Altgr. χλαῖνα chlāīna "coat" derived and refers to the hairiness that most species of the genus have. The species name velutinus ( Latin velutīnus, a, um ) means "velvety" and characterizes the type of hairiness.
Of the 16 European species of the genus Chlaenius , Chlaenius spoliatus and Chlaenius festivus are very similar to the species Chlaenius velutinus . According to a new conception, Chlaenius velutinus is a subspecies of Chlaenius festivus and would then be called Chlaenius festivus velutinus .
Chlaenius velutinus occurs in the two subspecies Chlaenius velutinus velutinus and Chlaenius velutinus auricollis .
Characteristics of the beetle
The beetle grows to thirteen to almost eighteen millimeters. The top is metallic green, the wing-coverts have a striking pale yellow edge. The body is more rounded than that of Chlaenius spoliatus .
The mouthparts point forward, the end links of the jaw and lip probes are spindle-shaped with a truncated tip. The forehead between the domed eyes is less wide than that of Chlaenius festivus , only about three times as wide as an eye. The eleven-limbed yellow antennae are thread-shaped and only from the fourth limb onwards are more densely hairy ( pubescent ) and therefore appear darker and more dull there.
The laterally bordered, heart-shaped pronotum is completely golden green or copper red and without a yellow border. It is clearly and irregularly dotted , less dense than in Chlaenius festivus . The posterior corners are less sharply rectangular than in Chlaenius festivus .
The green wing-coverts are clearly hairy and appear dull. The outer edge is provided with a light yellow wide stripe (Fig. 2). This is clearly narrowed towards the front ( hardly in Chlaenius spoliatus ); it widens towards the rear, but not several times in a step-like manner (as in Chlaeniellus vestitus ). The elytra are striped by rows of dots, the short row next to the label (scutellar stripe ) is followed by eight to nine further rows of dots. The intervals between the rows of points are all equally curved and finely dotted. The lateral edge of the elytra is turned under up to about the narrowing of the wing.
The legs are yellow. The tarsi are five-part. The spine at the end of the posterior splint is shorter than half of the first tarsal link (Fig. 1, in Chlaenius festivus it is longer). In the males, the three posterior tarsal links on the front legs are square.
biology
Beetles and larvae are predatory. The beetle can be found in damp places, preferably under stones on the banks of flowing and standing water. Especially in the south, it occurs on the banks of such streams that only carry water at times. The behavior patterns observed in such a temporary body of water in southern Spain are likely to be characteristic of southern countries. Accordingly, the animals can be found from February to July. Here is the distinct activity maximum of Imagines in April and May, when the propagation conditions are best. There are about as many females as males. Females with maturing eggs were found from February to June. The simultaneous findings of different age groups during the peak of activity show that the season, which is favorable for reproduction, is being fully exploited.
The eggs ripen quickly, and females can be found as early as March with the abdomen inflated by the large, ripe eggs. However, egg-laying does not peak until the second half of spring.
The females examined contained an average of about ten mature eggs during oviposition, often together with egg cells in earlier stages of development. Under laboratory conditions, the time from oviposition to hatching of the imago took a little over a month. While the mortality rate in the eggs was relatively high (almost 90%), over 80% survived each of the three larval stages and the pupa stage. This means that only about 4% of the eggs developed to the imago in the laboratory and it can be assumed that the laboratory conditions were suboptimal. The development times in the laboratory were about 5 days for the egg and the first two larval stages, the third larval stage lasted around two weeks and the pupa stage took around six days.
In July there are only a few young animals left. The life cycle is therefore usually one year, with favorable conditions a second generation is probably possible. During the unfavorable seasons, the animal rests as an imago.
The nimble larvae live in a density of up to ten individuals per square meter. They hunt mainly for fly larvae and small worms in the mud and in shallow pools of water with little vegetation. They show an unusually low level of aggression against each other for ground beetle larvae, although they compete with one another in terms of their prey. It is assumed that the frequent mutual contact with her almost body-long cerci reduce the aggression.
The larva uses m-cresol as a chemical defense against possible predators . Experiments have shown that the black mold beetle clearly prefers alternative prey animals without chemical defense means over the larva of Chlaenius velutinus .
distribution
The species is mainly found in the western Mediterranean including North Africa, but is also found in Greece . In Germany , Austria and Switzerland the species is rare and partly under protection. To the east, the distribution area extends over Hungary , the Ukraine and southern Russia to the Caspian Sea .
literature
Heinz Joy, Karl Wilhelm Harde, Gustav Adolf Lohse: The beetles of Central Europe . tape 2 . Adephaga 1. Elsevier, Spektrum, Akad. Verl., Munich 1976, ISBN 3-87263-025-3 .
Individual evidence
- ↑ a b c Chlaenius velutinus at Fauna Europaea. Retrieved August 23, 2011
- ↑ Sigmund Schenkling: Explanation of the scientific beetle names.
- ↑ Erich Kirschenhofer: "Taxonomic Changes in the Genus Chlaenius BONELLI, 1810" Entomofauna Volume 21, Issue 7: 57-64 Ansfelden, April 30, 2000 ISSN 0250-4413 as PDF
- ↑ AMCárdenas, P.Gallardo, R.Gonzáles, M.Hidalgo: "Biología de reprodrucción de Chlaenius velutinus (Duftschmid, 1812) en el sur de la Península Ibérica" Dpto. Biología Animal. Facultad de Ciencias. C / San Alberto Magno s / n. 14071 Cordoba. Recibido el 10 de noviembre de 1998. Aceptado el 9 de julio de 1999. ISSN 1130-4251 (1999), vol 10: 113-122. as PDF
- ^ A. Massolo, P. Brandmayr, T. Bonacci, T. Zetto Brandmayr Peace in ground beetle larvae: non-aggressive outcome in Chlaenius spp. larvae interactions Ethology Ecology and Evolution, Vol 16, No 4 (2004) as PDF
- ↑ Teresa Bonacci, Alessandro Massolo, Pietro Brandmayr, and Tullia Zetto Brandmayr: "PREDATORY BEHAVIOR ON GROUND BEETLES (COLEOPTERA: CARABIDAE) BY OCYPUS OLENS (MÜLLER) (COLEOPTERA: STAPHYLINIDAE) UNDER LABORATORY: 54 -551. 2006. Published By: The American Entomological Society doi : 10.3157 / 0013-872X (2006) 117 [545: PBOGBC] 2.0.CO; 2 as PDF at bioone
- ↑ E. Balestrazzi, ML Valcurone Dazzini, M. Bernardi, G. Vidari, P. Vita-Finzi and G. Mellerio: "Morphological and chemical studies on the pygidial defense glands of some Carabidae (Coleoptera)" Natural Sciences Volume 72, Number 9 , 482-484, doi : 10.1007 / BF00441073
Web links
- Determination table for the genus Chlaenius , guide numbers 1,2,3,6,7,8 (accessed August 24, 2011)
- Chlaenius velutinus at Fauna Europaea. Retrieved September 14, 2011