Skullcap leaf beetle
| Skullcap leaf beetle | ||||||||||||
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Skullcap leaf beetle Phyllobrotica quadrimaculata |
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| Phyllobrotica quadrimaculata | ||||||||||||
| ( Linnaeus , 1758) |
The skullcap leaf beetle ( Phyllobrotica quadrimaculata ) belongs to the leaf beetle family and the subfamily Galerucinae . The genus Phyllobrotica occurs worldwide in about thirty species, seventeen are native to the Nearctic , two in the Oriental region and ten in the Palearctic , three of which are found in Europe. Of these, in addition to the skullcap leaf beetle, only Phyllobrotica adusta can be found in Central Europe .
Notes on names and synonyms
.jpg) Fig. 1: Top view |
 Fig. 3: Engraving by Curtis from 1840 with detailed drawings of the mouthparts, the antennae and the foreleg |
 Fig. 2: side view |
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Video |
The beetle was already described in 1758 by Linnaeus under the name Chrysomela quadrimaculata in his famous 10th edition of the Systema Naturae . Linné cites extracts from an older description of the beetle by Gadd from 1751 , which contains the subset elytrorum punctis quatuor nigris ( Latin : with wings with four black dots). This explains the species name quadrimaculata (Latin with four points). The description by Gadd is much more extensive than that by Linné, but is not considered to be the first description, as it does not yet use the binomial nomenclature .
After the beetle was classified in the genus Chrysomela, the beetle was assigned to the genera Galeruca and Crioceris by various authors . Panzer calls the beetle Crioceris bimaculata . Due to a transmission error , quadripunctata was also used as the species name for the beetle instead of quadrimaculata .
The generic name Phyllobrotica appears for the first time in 1836 in the 5th delivery to the Dejean catalog from 1833. Dejean notes that he followed Chevrolat in naming it. The name is from altgr. φύλλον "phýllon", "leaf" and βρωτικός "brotikós", derived from "belonging to the food" and refers to the fact that the beetle eats leaves.
The German name expresses that the beetle is often found on the skullcap .
Description of the beetle
The five to seven millimeter long beetle has such eye-catching markings that it can already be seen in Curtis' engravings (Fig. 3), together with the wild garlic . (However, there is no biological relationship between beetle and plant.) The beetle is very shiny yellow, after death the color darkens and becomes reddish to brownish. The top of the body is bald. Each wing cover has two large brown to blue-black spots, the smaller one near the base, the larger one in front of the tip. The head is also black between the eyes up to the vertex, as is the rear breast and abdomen on the underside.
The forehead has two grooves. A longitudinal groove begins between the antennae and continues down to the fairly flat apex. Before it ends, it is penetrated by a transverse channel consisting of two weak arches. These grooves limit two frontal cusps. The eyes are large, strongly arched and broadly oval, their outer distance is greater than the width of the base of the pronotum. The eleven-link, thread-like antennae are longer than half the body. They are deflected on the forehead between the eyes. The third antenna element is shorter than the fourth and longer than the second, the following ones are roughly the same as the fourth, only the last one is shorter and ends in a cone. The mouthparts are shown in Fig. 3 below (1 upper lip, 2 upper jaw, 3 lower jaw with jaw probe, 4 lower lip with lip probe). The jaws are unusually thick, the end phalanx is short, conical.
The short, fairly flat pronotum is only about as long as the head. It is about one and a half times as wide as it is long. The front has just been cut off. It is broad on the sides but has a flat edge, but has no edges at the base. Its greatest width lies behind the center, the rear corners are obtuse angled, the front corners slightly rounded. A fine center line and a shallow transverse impression can be formed in front of the shields, but not a complete, deep transverse furrow. The transverse impression can also be broken up into two separate shallow pits. It can also enlarge in the middle to form a recess which is open towards the front and whose front part can be designed as a further separate recess.
The label is also much wider than it is long and rectangular to trapezoidal. It is not blackish as in Phyllobrota frontalis , but of the same color as the elytra .
The elytra are already wider than the pronotum at the base. They widen backwards moderately up to the third quarter, then they end together broadly rounded. Overall, they are twice as long as together wide. The elytra are very fine and tightly dotted . Their lateral margins are turned under laterally and are visible from above at most at the tip, but the elytra, however, have no set-off epipleurs . The black blemish at the base of the elytra is round and may be missing, this variation is called the munda . The rear blemishes are larger, transversely oval, and can also merge into a ribbon.
The anterior hip cavities are not closed. All tarsi are four-part. The claws are toothed at the root. In the male, the first tarsal link is significantly wider than the following. In addition, the underside of the abdomen is significantly different in the male than in the female. The three middle belly rings are shortened and arched transversely, the fifth is as long as the others together and drops off quite steeply towards the rear. In the middle of the first segment there is a wart-shaped cusp, behind which an initially narrow and fine impression begins, which widens and deepens towards the rear, but is interrupted and offset by the transverse arches, so that different pits are created (picture). In the female, however, the abdomen shows no special features.
Eggs and larva
The eggs are deep yellow and dull. They are almost spherical. The egg shell is densely dimpled, which gives it a grid-like appearance.
The larvae are elongated and almost cylindrical. They are a little less tapered towards the front than towards the back, the greatest body width is behind the middle. In the last stage, the larva becomes twelve to fourteen millimeters long and about two millimeters wide.
The head is shiny yellow-brown, the mandibles red-brown. The back part of the fore chest, the six legs, the top of the ninth abdomen segment, and the edges of the spiracles are yellowish. The rest of the body is soft and white in the last larval stage. In earlier stages, the larva has yellowish transverse spots on its back and roundish spots of the same color on the side. The body is very sparse, hairy on the head and legs a little more densely. On the top, the hair is only half as long as on the bottom.
The head is sunk deep into the first chest ring and only half as wide as this. There are two flat, wrinkled dimples on the forehead. Individual eyes are missing. The four-part antennae are inserted laterally, short and quickly tapering. The first link is thick and almost as long as the rest of the links combined. The second and third links are ring-shaped. The third link has an awl-shaped appendix on the inside. The fourth link is ovate and pointed and clearly longer, but only half as wide as the two preceding links. The head shield is clearly set off, brightly lined at the front and slightly bulged. The rounded upper lip protrudes under the head shield. It has four diagonally positioned hair-bearing dimples. The mandibles are short and strong, curved inward, with one small tooth on the outside and two on the inside. The maxillary probes are tripartite. The base link is very short and wide, the second link as long as it is wide, the end link the same length but conical. The inner compartment of the lower jaw ( Lacinia ) is rounded at the front and reaches half the height of the second jaw probe. It has a short row of five equally long, robust and shiny hairs as well as an inwardly directed chitin tooth. An outer box of the lower jaw is missing. The trapezoidal lower lip is as long as it is wide. The lip probes are two-part, clearly separated from each other, and two hairs emerge between their bases. The tongue is a little longer than it is wide, parallel-sided and truncated in front.
The five-limbed legs are short and strong. The hips are large and protruding and pivoted far apart. The trochanters are relatively large. Leg and rails are of the same length, the leg is cylindrical, the rail is conical. The claw is straight and pointed, inside an oval skin sac is formed at the root of the claw.
The first eight abdominal segments, like the two posterior breast segments, are divided transversely by folds. Viewed from the side, almost four times as many segments are simulated on the back, because each of the eight abdominal segments is divided transversely into proscutum, scutum and scutellum and also separated from the next abdominal segment by an intersegmental membrane. The intersegmental membranes are also present on the abdominal side, but do not form a continuous ring with the dorsal intersegmental membranes. The ninth abdomen segment is as long as it is wide and rounded at the back when viewed from above. The top is indented in a circle, the bottom of the impression is uneven. The last abdominal segment encloses the exit of the digestive tract and is therefore called the anal ring. The anal ring is extended by a slider that has a longitudinal furrow on the top and three suction cups on the bottom.
Spirals are located on the underside of the second breast segment and on the sides of the first through eighth abdomen segments.
biology
The beetle is tied to a damp, swampy habitat. It can be found in spring swamps and bogs, on swampy meadows, in breaks, on swampy banks and in alluvial forests in swampy places, mostly in partially shaded surroundings. Within these biotopes it is mainly to be found on its host plant, the skullcap .
According to W. Kolbe , the beetle eats deep, irregular bays in the host plant. This statement suggests that the beetle attacks the plant from the edge of the leaf. However, a closer examination of the feeding habits of different leaf beetles by Bieńkowski specifies that the beetle belongs to those leaf beetles that do not eat the leaves from the leaf edge. Rather, the beetle sits directly on the leaf surface at the beginning of its meal. The beetle turns its head at a slight angle perpendicular to the body axis and then takes a series of bites, successively turning the head and front chest parallel to the leaf surface in the direction in which the mouthparts are deflected from the body axis. Then he turns his head the other way and bites his way in the opposite direction. So he opens a small hole in front of him, which he enlarges and the front edge of which is determined by the reach of the upper jaw. By gradually pushing itself forward with every turn of the head, the hole enlarges towards the edge of the leaf and finally forms bays that end at the edge of the leaf.
The beetle appears on the host plant in May or June after the onset of warmer weather and can be found until August. It is not frequent. Mass occurrences are rather the exception. Due to its ability to fly, it can be found not only on the host plant, but also in its environment, for example on willows. When touched, the beetles pull their legs and let themselves fall. When held in the hand, they exude a yellowish, oily juice. In the shade they are sluggish and can pretend to be dead for a long time, but in sunny containers they are very lively, only briefly or not at all pretend to be dead when grasped. The willingness to mate also increases significantly in hot weather.
The numerous eggs are deposited near the ground on the stems or on the ground under the host plant. The beetle chooses the drier locations. The larvae hatch about four weeks after oviposition. They bore their way through the soil to the root shoots of the perennial host plant. They gnaw the white root shoots by moving along them. The beetle overwinters as a larva and pupates in the following spring. So the development is annual.
distribution
The beetle is classified as a Euro-Siberian fauna element. It is widespread in Europe. The northern border of the distribution area runs through Great Britain , Norway , Sweden and Finland . In the south, the beetle occurs in Italy and Greece . In the west, its occurrence extends to France . To the east, the distribution area extends beyond Europe to the Altai , the Sajan Mountains and Lake Baikal . A message from China is probably based on an error. In some south-east European countries the occurrence is not certain. There are also no reports of finds from the Iberian Peninsula .
The skullcap leaf beetle as an example of coevolution
The skullcap leaf beetle is an interesting example of the coevolution of plants and insects that feed on these plants. The skullcap leaf beetle Phyllobrotica quadrimaculata feeds in its circulation area (Eurasien) monophag from Skullcap Scutellaria gallericulata . However, Scutellaria gallericulata is also found in North America. There the plant serves as a host for the beetle Phyllobrotica decorata . Other species of the genus Phyllobrotica have other species of the genus Scutellaria as hosts: P. adusta on S. altissima , P. circumdata on S. integriifolia , P. costipennis on S. arenicola , P. sororia on S. drummondii .
literature
- Edmund Reitter : Fauna Germanica, the beetles of the German Empire, Volume IV, KGLutz 'Verlag, Stuttgart 1912, p. 140
- 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). P. 199
- Klaus Koch : The Beetles of Central Europe . Ed .: Heinz Freude . tape 3 : ecology . Goecke & Evers, Krefeld 1992, ISBN 3-87263-042-3 . P. 95
Individual evidence
- ↑ Phyllobrotica at Itis
- ↑ a b c Andrzej Warchałowski: The western Palearctic species of the genus Phyllobrotica Chevrolat, 1837 (Coleoptera, Chrysomelidae, Galerucinae) . In Annales Zoologici (Warszawa), 1998, 48 (1/2): 91-98 [1]
- ↑ a b Retrieved March 10, 2018 from Fauna Europaea
- ^ Chi-Feng Lee, Jan Bezděk: Revision of Phyllobrotica from Taiwan with description of Jolobrotica gen. N. (Coleoptera, Chrysomelidae, Galerucinae) . In Zookeys 2015; (547): 75-92 doi: 10.3897 / zookeys.547.9381 , PMC 4714334 (free full text)
- ↑ Carolus Linnaeus: Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis 1st volume, 10th edition, Stockholm 1758 p. 376 No. 65 4-maculata
- ^ Pehr Adrian Gadd: Försök, Til en Oeconomisk Beskrifning, Öfwer Satacunda Häraders Norra Del (Swedish, attempt at an economic description of the northern part of the districts of Satakunda ) Stockholm 1751 page 77
- ↑ Sigmund Schenkling: Explanation of the scientific beetle names (species)
- ↑ Georg Wolfgang Franz Panzer: Germany's Insect Faune or Entomological Pocket Book for the year 1795 Nuremberg (without printing date, foreword 1794) p. 169, no. 14
- ^ Dejean: Catalog des Coléoptères de la Collection de M. Le Comte Dejean Deuxième édition Paris 1833: Livraison 1 (p. 1–96), Livraison 2 (p. 97–176) Paris: Méquignon-Marvis Père et Fils, Livraison 3 (Pp. 177-256) 1834, Livraison 4 (pp. 257-360) 1835. p. 381
- ↑ Sigmund Schenkling: Explanation of the scientific beetle names (genus)
- ↑ Sketch of the underside of the male's abdomen ( 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.
- ^ V. Laboissière: Revision des Galerucini d'Europe et pays limitrophe (continued), in Annales de l'Association des Naturalistes de Levallois-Perret Levallois-Perret, 1909-1910 Vol. 19, p. 14. p. 43
- ^ Ludwig Redtenbacher: Fauna austriaca - Die Käfer second edition, Vienna 1858 p. 930
- ↑ WF Erichson et al .: Natural history of the insects of Germany 6th volume, Berlin 1893 p. 585 ff.
- ↑ Phyllobrotica at coleo-net
- ↑ Adam G. Böving, FC Craighead. An illustrated synopsis of the principal larval forms of the order Coleoptera. In: Entomologica Americana Vol. XI (New Series) March 1931 No. 4, plate no. 111 A, B, E at BHL
- ^ A b c W. Kolbe: Development and way of life of the Phyllobrotica 4-maculata L. In: Zeitschrift für Entomologie NF 27. Issue, Breslauf 1902 at BHL
- ↑ Adam G. Böving: Descriptions of larvae of the genera Diabrotica and Phyllobrotica, with a discussion of the taxonomic validity of the subfamilies Galerucinae and Halticinae (Coleoptera: Chrysomelidae). In: Proceedings of the Entomological Sociaty of Washington Vol. 29, No. 9, December 1927 Description p. 200
- ^ AO Bieńkowski: Feeding Behavior of Leaf Beetles (Coleoptera, Chrysomelidae) . In ISSN 0013-8738, Entomological Review, 2010, Vol. 90, No. 1, pp. 1–10 doi: 10.1134 / S001387381001001X [2]
- ^ Remigius Geiser: 12th report of the working group of Bavarian coleopterologists . In the newsletter of the Bavarian Entomologists 33rd year No. 3, October 1984 Munich p. 82
- ↑ A. Bukejs: Biogeography of Chrysomelidae sl (Insecta: Coleoptera) of eastern Baltic region (Latvia, Lithuania, and Estonia) . In СОВРЕМЕННЫЕ ПРОБЛЕМЫ ЭНТОМОЛОГИИ ВОСТОЧНОЙ ЕВРОПЫ Минск, 8-10 сентября 2015 г. ISBN 978-985-469-490-0 p. 16
- ^ Bryan D. Farrell, Charles Mitter, Douglas J. Futuyma: Diversification at the Insect-Plant Interface . In BioScience Vol. 42, N ° 1, Jan. 1992 pp. 34 - 42 digitized by University of California Press, Journals + digital Publishing, American Institute of Biological Sciences [3]
