Elophila nymphaeata
Seerosenzünsler ( Elophila nymphaeata )
The Seerosenzünsler or pondweed - borer ( Elophila nymphaeata ) is a butterfly (moth ) of the family Crambidae and belongs in the subfamily Acentropinae. The caterpillars develop, unusual for butterflies, mostly under water.
Features
The wingspan is 17-28 mm. The ground color of the forewing upper side is white with a light brown to dark brown drawing of transverse lines, dark spots and jagged edged binding. Most subbasale the cross line is still developed relatively clear. Frequently it has in the middle an outward stroke or narrow tooth. The inner transverse line is only weakly drawn, often almost extinct. The outer transverse line is only weakly indicated, often referred to as outward, often interrupted spikes binding. Sit several large, rounded, light-to dark -rimmed, white spots between inner and outer transverse line. Very clearly developed is a transverse oval to crescent-shaped spot near the outer transverse line, which sits close to the costal margin and the costal border is open. Another more roundish spot sits closer to the inner transverse line and closer to the inner edge of the wing. Two other small spots are developed at about the level of Diskalfleckes and at Kostal edge on the inner transverse line. Also, they are in the ground for Kostal border open, but are traversed by a longitudinal line that runs parallel to the costal margin almost to the outer transverse line. In the area of Submarginallinie is a series of elongated, inwardly usually jagged whitish points that are lined externally by a dark transverse line. The Saumfeld is light to dark brown, the hemline highlighted often dark brown. The fringes are pale gray-brown ( lighter than the Saumfeld, but much darker than the ground color of the forewing ).
The hind wings are also white in color. The drawing here is constant and clear. It consists of a strong inner transverse line and a strong, internally strong rebounding and white fringed outwardly outer transverse line. The midfield is almost pure white and has only two strong Diskalflecke on. The submarginale line is usually developed as a broad brown, outwardly directed prongs binding. Clearly drawn dark is usually the hemline. The fringes are brighter than the hem line, often spotted irregularly. The moths have a well-developed proboscis.
The drawing of something larger females is usually somewhat weaker than that of males.
The eggs are yellowish when filing .. They are flattened lenticular.
The caterpillars are about 22 mm long and have a yellowish to light green color. They are only slightly hairy.
The doll is 10.0 millimeters long and has a diameter of 3.0 millimeters. The only slight gloss doll has penetrated light brown and moderately. The cremaster is relatively short; he has three pairs of nearly equal size, dark stiff bristles.
Geographical distribution and habitat
The Seerosenzünsler is widespread in the northern hemisphere ( Holarctic ), wherever there are suitable habitats. The range of the species extends from northwestern North Africa to northern China, the Russian Far East and Japan (here with the subspecies E. nymphaeata ezoensis ). In Northern Europe, the area extends to the British Isles and into northern Sweden. In Asia the way southward occurs to Asia Minor, Cyprus and the Middle East and Iran, Uzbekistan and Afghanistan.
The Seerosenzünsler lives mainly on small, standing water, such as ponds, ditches and ponds and is widespread in Central Europe and frequently.
Way of life
The Seerosenzünsler forms in Central Europe two generations per year, with the first-generation moths fly in June, the moths of the second generation in August and September. In southern Europe up to three generations are formed. During the day, the butterflies hang upside down or with the belly up on or under plants of the riparian vegetation. They are crepuscular and nocturnal and come to artificial light sources. They will stay in areas of the shore region with high humidity, while sunlit, dry areas with little humidity are avoided. The evening activity depends on the occurrence of " Taufalles " ( = exceeding the 100 % saturation limit ). Therefore, on some days, the moths are active only hours before sunset, while they are only actually on other days in one or even active at dusk. The activity of the moths is also temperature dependent. When evening temperatures below 10 ° C, the moths do not fly. In the nights the activity ceases when the temperature drops below 11 ° C. Under favorable conditions, the maximum flight activity about 60 - reaches 70 minutes after sunset. The males fly it around 10 to 20 inches above the water level. The females attach themselves just a short flight search on a pondweed flower or a plant stem. The males are attracted by pheromones; copulation takes place on the resting place of the females. Pairing takes 20 to 40 minutes; after mating, both partners fly back to shore.
Oviposition begins 15 to 20 hours after copulation in the afternoon of the following day. After a search, the female flight lands on a water lily leaf pondweed or. This must be wider than the span of the legs of the female. The female then pushes his abdomen under the sheet. The eggs are deposited in layers on the caterpillar food plants just below the water level. The clutch sizes are very different (from about 400 to very few, about 3 eggs). The mean number of eggs laid per female is about 340 eggs. The male moths are up to 18 days old, on average 11 days, while the female moths die already 2 to 3 days after oviposition.
The caterpillars hatch after 10 to 11 days ( close to 20 ° C mean water temperature). With cold weather, the Schlüpfzeitpunkt may a few days delay (up to approximately 14 days). Most Eiraupen leave the immediate surroundings of the scrim and creep on the underside of the surface tension to adjacent sheets. Some of the young caterpillars nate initially in stems and leaves. Other Eiraupen feed directly on the leaves. The Minier stage lasts a maximum of four days. Then customize it yourself small, weak spun quiver from 4 to 6 mm long and 2-3 mm wide leaf pieces. The quivers are filled with water and pieced at the bottom of the sheet on which the caterpillars eat. Caterpillars breathe in this phase on the skin surface.
According to the two generations of caterpillars in May and then to meet again in August. They feed on floating pondweed ( Potamogeton natans ), water knotweed ( Polygonum amphibium ), water lilies (Nymphaea ), easy bur-reed ( Sparganium emersum ) and Small duckweed ( Lemna minor). The caterpillars of the first generation to be hydrophobic to hydrophilic two stages; followed by two more caterpillars stages until pupation.
The caterpillars of the second generation grow more slowly than the caterpillars of the first generation due to the slowly decreasing temperatures in September and October. From a water temperature of 10 to 11 ° C, they set the food. You walk with her quiver along the stem to a depth of 20 to 50 centimeters. There they attach the quiver in still green stems and drill a 10 to 15 millimeters long corridor in the pith of the stem. Reichholf found the overwintering caterpillars only in the stems from the Floating pondweed ( Potamogeton natans ). An important prerequisite for the successful wintering of the stems were also passed in the spring still green and not decay. Even the temporarily dry traps will not harm the overwintering caterpillars. In spring, the caterpillars leave their hiding place and stems crawl up to the stems. They finished last year's leaves from a new quiver and start at any accessible green leaf to eat. After a few days they shed their skin and the beads are hydrophobic, ie the surface of the bead is no longer wetted, but is surrounded by an air cushion. The caterpillar stretched over and over again, the front end in the air and replaced by back-and- forth - moving the front body, the air in her quiver. The hydrophobic substances originate most likely from the food of the caterpillars because they eat just before the transition from hydrophilic to hydrophobic on the tops of the pondweed or lily pads, which are hydrophobic. If already hydrophobic caterpillars fed on lettuce or hydrophilic water plants, they become hydrophilic again. Re- feeding with hydrophobic water plants leads back to the hydrophobicity of the caterpillars. The hydrophobic Caterpillar also manufactures a container of two elliptic leaf pieces that are spun by spinning threads together. It is during a crawler stage times renewed six to eight, the leaf pieces cut out always something bigger. It contains air, the penetration of water is prevented by the firm spun edges and a fine coating of filaments inside the quiver. The quiver is pulled behind while crawling; to eat the caterpillar sticks her head out of the container. The caterpillars molt one more time with about 17 to 19 mm body length. They are fully grown in late May and now manufacture a special dolls quiver. This is fixed in about 1 to 12 cm depth below the surface of the stems of the caterpillar food plant. Most of the last tracked quiver is used and only woven tightly together. More rarely, a new quiver is made. In the literature it is frequently read that the caterpillar bite the plant tissue to retrieve it from the aerenchyma of the plant oxygen. But the doll does not require oxygen from the plant tissue and the bite the stem serves for better attachment of the Dolls quiver on the plant. The pupal period lasts depending on the water temperature 12 to 16 days. The moths emerge therefore from late May to early June from their pupal cocoon under water. The folder will be protected by special scales that are long, narrow and almost hair -like, before wetting. After surfacing, he initially runs like a water strider on the surface film of the water until the next sheet. They rest there until the excretion of Meconiums.
In the overview, this results on average than development time for the summer generation:
- Egg stage ( until hatching ): 10 days
- Hydrophilic bead ( 2 stages ): 20 to 25 days
- Hydrophobic bead ( 2 stages ): 25 to 30 days
- Pupal period: 12 to 16 days;
That is, a total of 70 to 80 days from egg laying to hatching of the moth.
Systematics and Taxonomy
The species was described in 1758 by Carolus Linnaeus, under the name Phalaena Geometra nymphaeata first time scientifically. It is the type species of the genus Elophila Hübner, 1822. In earlier publications it appears also in the combinations Nausinoe nymphaeata and nymphula nymphaeata. Speidel (2005) distinguishes five subtypes:
- Elophila nymphaeata nymphaeata that nominotypical subspecies, Europe, Siberia
- E. nymphaeata hederalis ( Amsel, 1935), Israel
- E. nymphaeata silarigla Speidel, 1984, Morocco and Algeria
- E. nymphaeata Auralis Easter Helder, 1935, Turkey, Cyprus, Iran, northern Afghanistan and Uzbekistan. Transitional forms between the subspecies E. nymphaeata nymphaeata and E. n Auralis were observed in Northern Iran.
- E. nymphaeata ezoensis Yoshiyasu, 1985, Hokkaido (Japan), Russian Far East and North China (Province of Heilongjiang and Xinjiang ).
Chen, Wu and Xue (2010 ), however, lead ezoensis Yoshiyasu, 1985 under the synonymy of Elophila nymphaeata nymphaeata, so assume that is that they only accept four of the above five subspecies (plus an unnamed subspecies from Ireland). The area of the nominotypischen subspecies would extend this view to Japan and northern China.