Acentria ephemerella
| Acentria ephemerella | ||||||||||||
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Acentria ephemerella |
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| Systematics | ||||||||||||
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| Scientific name of the genus | ||||||||||||
| Acentria | ||||||||||||
| Stephens , 1829 | ||||||||||||
| Scientific name of the species | ||||||||||||
| Acentria ephemerella | ||||||||||||
| (Eversmann, 1842) |
Acentria ephemerella is a butterfly (moth) from the family of Crambiden (Crambidae). It is the only species in the genus Acentria .
features
Generic characteristics
Ocelles are not trained. The so-called ocelles observed in a male by Bürgis in 1992 were probably artifacts. The antennae of the males have short eyelashes. The maxillary palps are tripartite, the trunk has receded. The labial palps consist of two segments and are densely scaled . The legs are relatively short and have the spur formula 0-2-3. Only a medial spur is formed on the hind tibia . The spurs are very short and partially covered by scales. On the forewings, the R 2 vein arises freely from the cell , the R 3 and R 4 veins have long stalks. The CuP vein is absent on both the fore and hind wings. On the hind wing, the vein M 1 is connected to the stem of Sc + R 1 + RS by a transverse vein. The frenulum consists of a single bristle in both males and females. In females, there is a form with receding wings that lives exclusively in water. The praecinctorium is replaced by a rounded, sclerotized plate. In contrast to all other representatives of the Acentropinae, the spinula of the tympanic organ is absent .
The males have a broad gnathos that curves sharply distally and has some sclerotized teeth apically . The blades have no special features, they are significantly wider at the base than at the distal end. The aedeagus is very long and graceful. The apophyses anteriores are clearly widened like a lobus at the base. A colliculum is not developed. The corpus bursae is only very slightly sclerotized and has no signs. The seminal duct does not form an adjoining sac.
Species features
The moths reach a wingspan of 11 to 18 millimeters, the latter number referring to the winged females. The forewings are white in the males and winged females and have a light gray-brown tint. The hind wings are white. In the females the antennae are very short and graceful, in the males they are stronger and longer.
In the males, the uncus is short and blunt. The gnathos is wide at the base and has a sharp point. The blades are short and significantly wider at the base than at the distal end. They have no special characteristics. The juxta is long and oval. The aedeagus is very long and graceful, it widens distally .
In females, the oviscapter is very short and strong. The corpus bursae is membranous and has a small accessory sac. The ductus bursae is clearly not pronounced.
The caterpillars have no tracheal gills . Adult caterpillars are almost transparent and have a greenish tint that comes from the contents of the digestive tract. The head, prothoracic shield and sternum are pale brownish. Shortly before pupation, the color changes to a yellowish white. The stigmas are closed by a membrane, the caterpillars breathe through their skin. The nub-like belly legs are provided with elongated oval, closed or outside and inside open, double-row hook rings. The protruding caudal edge of the abdominal bones has greatly enlarged hook rings.
The doll has relatively short legs. It is ocher yellow; one can distinguish the sexes and morphs based on their shape. The trunk is very short. The wings are always fully developed in the males and extend to the 5th abdominal segment. In the pupae of the females, the wings are significantly shorter and reach the middle of the 4th abdominal segment. They hatch butterflies with fully developed wings. There is also a shape in which the wings only cover the 3rd abdominal segment. Females with receding wings hatch from these pupae. The plastron structures of the last caterpillar stage and the wingless females were published in 1987 by Messner et al. described in detail.
distribution
The European range of Acentria ephemerella extends in the north to the British Isles (including Ireland ), to the south of Norway , the north of Sweden and Finland . The southernmost evidence comes from southern Portugal and Corsica . In the southeast, the species occurs in the Turkish provinces of Konya (near Akşehir ) and Ankara . In Greece , the species was detected in 1997 by Fiebiger at Amindeon . In addition, the species occurs in North America in Canada ( Ontario , Québec ) and the USA ( Massachusetts , New York , Wisconsin ). It is believed that the species was introduced into the Nearctic . There is also the possibility that the species is native to similar habitats in Siberia, as it is very often overlooked due to its unusual behavior in light (see section Biology).
biology
The male moths rest near the water during the day. They are hydrophobic and are not wetted by the water. They are nocturnal and buzz restlessly above the surface of the water. The females with receding wings come to the surface of the water for copulation and attract the males. The female grabs the male and pulls him into the water. The females lay 115 to 250 eggs. These are greenish and oval, slightly wider at one end and have a weakly indicated incision in the middle. When egg-laying space is limited, the eggs are either laid in multiple layers on wide leaves or in rows on narrow leaves. The female places unfertilized eggs on her body.
The egg stage lasts 12 to 31 days. Only very young caterpillars occasionally mine in stems or leaves, a small number of caterpillars eats defenseless on the host plants. Older caterpillars fold the leaf margins so that they touch or they make housings. The caterpillars overwinter in the stalks of the host plants. These include pondweed ( Potamogeton pectinatus ), Potamogeton perfoliatus ( Potamogeton perfoliatus ), Potamogeton Crispus ( Potamogeton crispus ) Reflective pondweed ( Potamogeton lucens ), thread-leaved pondweed ( Potamogeton filiformis ), Ceratophyllum demersum ( Ceratophyllum demersum ), milfoil ( Myriophyllum ), water chestnut ( Trapa natans ), Wasserpest ( Elodea ), water knotweed ( Polygonum amphibium ) frogbit ( Hydro morsus-ranae ), grass pondweed ( Potamogeton gramineus ) zannichellia palustris ( Zannichellia palustris ), seaweeds ( Zostera ) and Great Mermaid ( Najas marina ). Acentria ephemerella is common in some Danish fjords. The salt content is up to two percent, the host plant is Zostera maritima under these conditions . Up to 300 caterpillars were found on the seagrass leaves.
In the last stage of the caterpillar, the abdominal segments 2 to 6 are strongly thickened and the areas around the spiracles are apparently silvery white due to the adhering air. The thickened part presses against the cocoon, which the caterpillar spins before pupation, so that it is completely filled with air when it is completed. The trachea of the pupa are connected to the air-filled cocoon by three pairs of protruding spiracles. In addition, there is direct contact between the cocoon surface and the aerenchyme of the host plant, as the adult caterpillars gnaw on the stem before pupation. The wingless females are enveloped in silvery white air on the underside of the abdomen.
For pupation , the longer side of the housing is attached to a stem.
The adults are hardly protected against dehydration, so winged females in particular can only be observed in the light when the air humidity is high - for example after a thunderstorm. Occasionally the species appears in large numbers in the light. The moths show unusual behavior in that they buzz around without a break near the ground until they die. The moths fly continuously from May to September, according to another source the first moths fly as early as mid-April.
According to Ritsema 1878, a small parasitic wasp parasitized in the pupae. This spins a cocoon inside the doll.
Systematics
The following synonyms are known for the genus Acentria :
- Zancle Stephens , 1833
- Acentropus Curtis , 1834
The following synonyms are known for Acentria ephemerella :
- Tinea ephemerella [ Denis & Schiffermüller ], 1775
- Phryganea nivea Olivier , 1791
- Bombyx phryganea Huebner , 1809b
- Bombyx sembris Huebner , 1809
- Setina ephemera Huebner , 1819
- Acentria nivosa Stephens , 1829
- Zancle hansoni Stephens , 1833 noun nudum
- Acentropus garnonsii Curtis , 1834
- Acentropus newae Kolenati , 1858
- Acentropus latipennis Möschler , 1860
- Acentropus neuae obscurus Tengström , 1869
- Acentropus badensis Nolcken , 1869
- Acentropus germanicus Nolcken , 1869
supporting documents
- ↑ a b c d e f g h i j k l m n o Barry Goater, Matthias Nuss, Wolfgang Speidel: Pyraloidea I (Crambidae, Acentropinae, Evergestinae, Heliothelinae, Schoenobiinae, Scopariinae) . In: P. Huemer, O. Karsholt, L. Lyneborg (eds.): Microlepidoptera of Europe . 1st edition. tape 4 . Apollo Books, Stenstrup 2005, ISBN 87-88757-33-1 , pp. 51 (English).
- ↑ Messner, B .; Groth, I .; Messner, U. (1987): The plastron structures of the larva, the pupa and the submerged female of Acentria nivea (Olivier, 1791) (Lepidoptera, Pyralidae). Zool. Jb. Anat. 115: pp. 163-180.
- ↑ Karl Traugott Schütze: The biology of the small butterflies with special consideration of their nutrient plants and times of appearance. Handbook of Microlepidoptera. Caterpillar calendar arranged according to the illustrated German Flora by H. Wagner. Verlag des Internationale Entomologische Verein e. V., Frankfurt am Main 1931, p. 93
- ^ A b Acentria ephemerella in Fauna Europaea. Retrieved October 20, 2012
Web links
- University of Konstanz - photos of egg layers, caterpillars, feeding pictures and butterflies
- Lepiforum e. V. - Taxonomy and photos
- Ian Kimber: Guide to the moths of Great Britain and Ireland .