Chalkhill Blue

Silver Green Blue ( Polyommatus coridon ) ♂

The Silver Green Blue ( Polyommatus coridon ) is a butterfly ( butterfly ) of the family Lycaenidae ( Lycaenidae ). The species colonized dry and sunny, slightly vegetated habitats and comes despite the decline of these habitats usually still frequently and in large numbers of individuals before. As with many Bläulingen the caterpillars of the Silver Green Bläulings live in symbiosis with ants.

• 3.1 Flight times and caterpillars
• 3.2 food of the caterpillars

Features

Imagines

The moths reach a wingspan of 30 to 35 millimeters. The upper wing of the males are brightly colored silvery- green to blue, the outside of the wing edge, they are dark. The blue can be configured differently depending on the occurrence and subspecies. The outer edge is white fringed with dark spots.

The females come in two color options. In one variant, the wing tops are dark brown, dusted little bluish at the base and wear along the outer edge, powerful at the rear wing, front only weakly, a series of orange, on the outside black colored spots. In the other variant, the wing tops are intense blue colored than the males and have in front of the outer edge ( Submarginalregion ) a brown color.

The underside of the forewing is similar to that of the otherwise by the strong blue colored top easily distinguishable Sky Blue Bläulings ( Polyommatus bellargus ). In the male, the color is pale gray-brown, dark brown in the female. The wing base shimmers slightly turquoise blue. The black spots on the undersides of the forewings are usually highly colored. Approximately centrally on the underside of the hind wings is a white spot, which is extended to the wing outer edge to a Spitz. He points at a white longitudinal wiping that sits between the orange, more or less triangular patches along the outer edge. These spots are edged with fine black to the front, rear is sitting a black dot. From Eros Blue ( Polyommatus eros ), the species differs mainly by the wing undersides. The sharp solid stain is clearly cored dark in this more or less, and the black spots are distributed differently.

Crawler

The caterpillars reach a body length of about 16 millimeters. You have a green base color and wear on both sides of the back rows of yellow spots, yellow longitudinal stripes on the sides and a fine, bright hair. You can see the caterpillars of the Sky Blues Bläulings very similar, but have a lighter green as the base color and indistinct trained yellow spots.

Similar Species

• Cerulean Blue ( Polyommatus bellargus )
• Eros Blue ( Polyommatus eros )

Subspecies

P. coridon forms in some places, for example in Chelmos Mountains in Greece, with various other Bläulingen natural hybrid, which complicates the taxonomic classification. The populations in Spain are particularly poorly classified. Because many questions are still unanswered, and some authors view different subspecies as separate species, the following list of sub-species is only provisionally.

• Polyommatus coridon coridon ( Poda, 1761 ); Northern Spain Pyrenees
• Polyommatus coridon caelestissima ( Verity, 1921); eastern Spain
• Polyommatus coridon asturiensis ( de Sagarra, 1924); Northern Spain
• Polyommatus coridon gennargenti ( Leigheb, 1987); Sardinia
• Polyommatus coridon nufrellensis ( Schurian, 1977); Corsica

Occurrence

The animals come from the north and east of Spain over central and southern Europe ( Central Italy, Corsica, Balkans) east to the Ukraine and the Urals before. To the north extends the distribution area across the south of England, Northern Germany and the bulk of the Baltics. In Germany, the species occurs in the southern highlands and in the Alps relatively common in the north it is rare. The earlier in Austria in the Alps or in the foothills often very common type is regression in a long time. The animals live on dry grass and other dry, sunny and temperature beneficiary, covered only with scattered bushes and short grasses areas, but only on calcareous, alkaline soils.

Way of life

The adults suck nectar mainly of oregano (Origanum vulgare). Absence of these plants, Common bird's-foot trefoil ( Lotus corniculatus ) is preferred, one also finds the animals but to pigeon - Scabiosa ( Scabiosa columbaria ), meadow (Centaurea jacea ), Marsh knapweed (Centaurea scabiosa ) and at least occasionally, the other in habitat existing flowers. Legumes play differently than other Bläulingsarten only a minor role as nectar plants. Frequently one finds the butterfly on gravel, where they suck in moist places. They usually occur in larger groups. In the evening they gather to sleep slightly elevated locations, such as on the vegetation somewhat superior umbellifers head down.

Flight times and caterpillars

The moths fly in one generation a year from late June to August maximum in early October. In the south, flying two generations from May to June and from August to September. The caterpillars can be found in central Europe from April to June.

Food of the caterpillars

The caterpillars feed mainly on the ordinary horseshoe vetch ( Hippocrepis comosa ), rarely they are also found on Colorful Kronwicke ( Securigera varia) and bear pepper ( Astragalus glycyphyllos ).

Development

The females lay their eggs singly from whitish at the base of the stem, the leaf axils and rarely on the leaves of the caterpillar food plants. Sometimes they are also stored on the nearby grass and stones. The females fly it flat over the vegetation and land some distance away on a non-vegetated place to travel on foot the rest of the way to the nesting beach. The vegetation is betrommelt going after touching the caterpillar food plants of the abdomen is curved to lay their eggs. After a few eggs were sold, is drawn in the meantime nectar.

Overwinter The eggs, the caterpillars hatch until the following spring. Only in Greece the caterpillar hibernates after the first moult under stones near ant nests. The caterpillars live myrmekophil together with ants. Symbioses are using some garden ants ( Lasius ) and Myrmica species, with Plagiolepis vindobonensis, with the commons lawn ant ( Tetramorium caespitum ) and with the Red Wood Ant (Formica rufa ) is known. The caterpillars but over glands of attractants that attract ants. Also, but on being touched by ants sensor through a gap at the back of the seventh abdominal segment a sweet secretion that eat the ants. On the eighth abdominal segment there are two vorstülpbare extensions, wearing a wreath of barbs at the end. These two organs are particularly moved when ants are nearby and they should probably attract as well. In addition to protection from predators ants build sometimes " shelters " of loose soil for the caterpillars, which may also have connections to the nearby ant nests.

The crepuscular and nocturnal caterpillars sit during the day in groups in the gravel or moss among the food plants. These plants can then acknowledge the many ants on the low-lying branches. Pupation takes place under stones, the doll is smooth and olive green.

Threats and conservation

In Germany the Silver Green Bluebird in many places still to be found frequently, though its habitat is being increasingly destroyed. Since the nature, in contrast to the significantly more sensitive sky Blue Blue ( Polyommatus bellargus ), is more tolerant of interference and for example also on embankments, roadsides and railway embankments occur, their existence is not endangered; The species is not listed in the Red List of Germany. However, it is endangered in several northern provinces, in Lower Saxony, she is at high risk ( category 2 ), even threatened with extinction in Saxony. In Austria, the species is in regression.