Isabella spinner
| Isabella spinner | ||||||||||||
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Isabella spinner ( Graellsia isabellae ), preparation of a male |
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| Scientific name of the genus | ||||||||||||
| Graellsia | ||||||||||||
| Grote , 1896 | ||||||||||||
| Scientific name of the species | ||||||||||||
| Graellsia isabellae | ||||||||||||
| ( Graells , 1849) |
The Isabella spinner ( Graellsia isabellae ) is a butterfly from the family of the peacock moth (Saturniidae). It is the only species of the genus Graellsia to which it has been added since 1896 and again after an investigation by Ylla, Peigler & Kawahara in 2005. In between it was assigned to the closely related genus Actias . It is the most basic representative of the Actias and Argema lines , from which it was the first species to split off. The cold-adapted species has an island-like distribution in southwestern Europe and is therefore protected in Spain and France. The species is distinctive in Europe due to its size and color. It colonizes pine forests, as the caterpillars in nature feed exclusively on these plants. The species is named after the Queen of Spain, Isabella II.
features
butterfly
The moths have a wingspan of 65 to 90 millimeters (males) or 70 to 100 millimeters (females), although animals from breeding are often significantly smaller. The animals are green in color, similar to Actias luna , which is common in North America , but differ from this species in their wing veins , which are strongly edged with reddish-brown scales , the equally edged front edge and edge, and the yellow-green color on the tails of the hind wings on the submarginal regions The pale green color is replaced up to the hem and at the base of the wings. The broad, outwardly curved tails are more than twice as long in males as in females. A short, postbasal, concave transverse ligament and a submarginal, strong double ligament are formed. The outer of the double bands, which is drawn somewhat blurred, ends in front of the wing tip. The antennae are dark red-brown in the male and have comb teeth that become shorter towards the tip and base, making the antennae appear leaf-shaped. The head and thorax are brown-purple with a lemon-yellow collar and epaulettes. The abdomen is brownish-purple in color and has yellowish-gray rings on each segment. The reddish brown eye spot is transparent in the middle and surrounded by yellow and black. The wings are slightly translucent. The species is very variable in shape and color and there are also strong differences in body size and formation of the pattern or color in animals of the same egg clutch.
The females differ from the males by their thinner, only short and finely toothed antennae and their wider fore wings. The outer edge of the forewings in the female is slightly convex and not slightly curved inward, and the wing tip is more angular. The tails of the hind wings are much shorter and more pointed in the female.
egg
The oval eggs measure 2.0 by 1.8 millimeters, but are tapered dorsally. They are cream in color with dark, olive green spots. The micropyle is easily recognizable.
Caterpillar
The caterpillars are 70 to 80 millimeters long. After hatching, they are about five millimeters long. During the first three stages, the caterpillars are predominantly gray-brown, with irregular spots and bumps, mimicking the appearance of the small twigs on which they sit. In the fourth instar, most of the caterpillars resemble those of Actias selene , but have a gray-brown base color with some green, brown and yellow irregular spots. The neck shield has four spikes. In the fifth instar, the animals are apple-green and covered with small white dots from which a few, long brown hairs emerge. The caterpillars have a broad, brown back band with a white border. There is a dull red ring on each segment, interrupted by two to three white spots on each side. The segments on the thorax are provided with yellow rings. The abdomen and head of the caterpillars are red-brown.
First instar caterpillar
Second instar caterpillar
Third instar caterpillar
Fourth instar caterpillar
Doll
The pupa is 32 to 35 millimeters long. It is mahogany brown and its shape is similar to that of the Viennese night peacock ( Saturnia pyri ).
Occurrence and habitat
The species occurs in Spain in the mountainous regions of central Spain, such as the Sierra de Guadarrama , the Montes Universales , the Sierra de Javalambre and the Sierra Gudar , in southern Spain in the Sierra de Segura , the central and eastern Pyrenees of Spain, in the Roncal Valley and in the Sierra de Montgrony . From there the distribution area extends to southern France. They can also be found in a small area of the high mountains in south-east France around Briançon and in the canton of Valais . The species was first detected there in 1987 and is now considered to be permanent. However, it is unknown whether the species flown in there or was introduced by humans. The latest reports from northern Italy still require confirmation.
The animals inhabit old pine forests between 500 and 1800 meters above sea level. In the canton of Valais they can be found in sparse pine forests on southern slopes between 800 and 1,600 meters above sea level. They can withstand relatively large fluctuations in temperature and humidity, but cannot withstand extreme heat and long periods of drought. The species adapted to the cold could probably have been much more widespread during the interglacial warm periods. After the end of the last ice age, however, the species may not have adapted quickly enough to the strong warming, so that it was trapped in the colder southern mountain regions without being able to repopulate the northern areas.
Way of life
Both sexes of the nocturnal species fly from dusk. They fly from a temperature of only 5 ° C. Mating takes more than two hours. The moths rest on trunks, young trees and small branches near the forest floor. The males in particular flap their wings. They are very well camouflaged.
Flight and caterpillar times
Depending on the altitude and the associated beginning of spring, the moths fly in one generation between March and early July.
Food of the caterpillars
The caterpillars feed exclusively on the needles of pines ( Pinus ), such as Scots pine ( Pinus sylvestris ) and various subspecies of the black pine ( Pinus nigra ). In breeding, however, sweetgum trees ( Liquidambar ) are also accepted.
development
The females lay their eggs individually or in small groups at the base of young pine needles. The caterpillars hatch after 10 to 15 days. At first they partially eat the egg shell. Initially, the caterpillars sit on the pine needles. From the second stage, most animals sit upside down at the base of the needles or on an exposed, older branch. There they are well camouflaged by their coloring. Almost without exception, older needles from the previous year are eaten up to the fourth stage. The individually living, fully-grown caterpillars often inflate the front body segments when resting, so that they resemble a pine cone. Development can take up to two months in cool conditions. During this time, a large number of pine needles are eaten, which is why younger, at least somewhat matured needles are occasionally eaten. Under ideal conditions, the caterpillars go through four instead of five stages, and in the fourth stage they develop their final color. Pupation takes place in a thin-walled, uneven to elongated, tapered, unlocked, golden-brown cocoon, measuring an average of 55 by 30 millimeters . Dead pine needles are worked into it. The cocoon is mainly spun at the base of the food plant either in the middle of dead needles or between the needles and the ground. It is mostly horizontal, with the exit opening dorsally at the thicker end. The pupa is very cold-resistant and can remain in place for more than a year in mild winters.
The Tachinidae Compsilura concinnata , Drino inconspicua , Masicera silvatica and Phaonia signata , and probably also the parasitic wasps Pimpla robusta , mongoose microstictus and mongoose sulfuripes are parasitoids of the Isabella moth.
Hazard and protection
The species is widespread, but only in populations that occur locally with small numbers of individuals . It is under protection in southern France and Spain.
Taxonomy and systematics
The Isabella spinner was first described in 1849 as Saturnia isabellae by Mariano de la Paz Graëlls y de la Aguera based on an animal found in the Sierra de Guadarrama on Monte de Pinares Llanos . In 1896 Augustus Radcliffe Grote placed the species in the monotypical genus Graellsia . Wolfgang Nässig synonymized this genus in 1991 with the closely related genus Actias , as he assumed, due to the external similarities, that the genus Actias was otherwise paraphyletic . An investigation on the basis of morphological, molecular and phenological characteristics from 2005 showed, however, that the separation of the two genera seems justified, although the Isabel spinner can even be hybridized with several species of the genus Actias in the laboratory.
supporting documents
Individual evidence
- ↑ a b c d e f g h i j k l m n Saturniidae of Europe. AR Pittaway, accessed April 1, 2011 .
- ↑ a b c d e Josef J. de Freina, Thomas J. Witt: Noctuoidea, Sphingoidea, Geometroidea, Bombycoidea . In: The Bombyces and Sphinges of the Western Palaearctic . 1st edition. tape 1 . EFW Edition Research & Science, Munich 1987, ISBN 3-926285-00-1 , p. 390 f .
- ↑ Isabella Spinner. Lepiforum eV, accessed on April 4, 2011 .
- ↑ J. Ylla, RS Peigler, AY Kawahara: Cladistic analysis of Moon Moths using morphology, molecules and behavior: Actias Leach, 1815; Argema Wallengren, 1858; Graellsia Grote, 1896 (Lepidoptera: Saturniidae) , SHILAP Revista de Lepidopterología, septiembre, año / vol. 33, número 131, Sociedad Hispano-Luso-Americana de Lepidopterología, Madrid 2005, pp. 299-317.
literature
- Josef J. de Freina, Thomas J. Witt: Noctuoidea, Sphingoidea, Geometroidea, Bombycoidea . In: The Bombyces and Sphinges of the Western Palaearctic . 1st edition. tape 1 . EFW Edition Research & Science, Munich 1987, ISBN 3-926285-00-1 .
