Large hop rootworm

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Large hop rootworm
Large hop rootworm, Hepialus humuli, female

Large hop rootworm, Hepialus humuli , female

Systematics
Class : Insects (Insecta)
Order : Butterflies (Lepidoptera)
Family : Rootworm (Hepialidae)
Subfamily : Hepialinae
Genre : Hepialus
Type : Large hop rootworm
Scientific name
Hepialus humuli
( Linnaeus , 1758)

The great hop rootworm ( Hepialus humuli ), also just called the hop rootworm or ghost moth (after the English name ghost moth ), is a butterfly ( moth ) from the family of rootworms (Hepialidae). The reason for the name "ghost moth" is the ghostly appearance of the males who buzz over the meadows after sunset.

features

Males and females show pronounced sexual dimorphism . The males have a wingspan of 48 mm (40–70 mm in length), the females are slightly larger (50–75 mm) with a wingspan of about 57 mm. The wings are relatively long and narrow. The fore and hind wings of the male are colored silvery white. The costal edge and the cilia are tinted slightly ocher. The forewings of the female are light yellow, ocher-yellow to yellow-brown in color, while the hind wings are ocher-gray or yellowish-gray and tinted with pink. The head, thorax and abdomen of males and females are colored light ocher brown to yellow. The antennae are simple and short. The females show a very variable pattern of darker (darker than the basic color) lines and spots on the forewings. The males have brush-shaped odor organs on the tibiae .

The relatively small eggs are oval and shiny white after being laid. They are 0.7mm long and 0.5mm in diameter. They turn glossy black within a few hours of being deposited.

The caterpillars are up to 40 mm long. The body is white or gray-white and has clear gray-brown spots. The neck plate is red-brown and has a sloping black drawing on both sides. The black egg-shaped stigmas stand out clearly. The head capsule is shiny reddish brown or yellowish brown, the anal plate light yellowish brown.

The elongated pupa is dark brown (to light brown). On each of the abdominal segments 3 to 7, it has two bands with bristles pointing backwards. The abdominal segments 4 and 5 have two crescent-shaped cutting plates on the belly side, and the abdominal segment 7 has a single large crescent-shaped, serrated cutting plate that connects to the bristles on the back. The Kremaster shows some small conical points.

Geographical distribution and habitat

male
male

The distribution area of ​​the great hop rootworm stretches from northern Spain to the Caucasus and Armenia, in the east to Siberia. In the north it stretches from (Central) Scandinavia and the British Isles, including the Faroe, Shetland and Orkney Islands to Sicily. However, the species is absent on the islands of Corsica, Sardinia and Crete.

Typical habitat of the big hop rootworm are farm meadows, in rather cool, humid landscapes, on the edges of fields and roads, dams, embankments, in orchards, in green areas and gardens on the edge of towns, also mountain and valley meadows and brook edges and ditches, more rarely also wet meadows on the edge of moors and clearings in damp forests. In the Alps, the species rises up to 2000 m above sea level.

Way of life

The great hop rootworm is usually univoltine ; d. H. one generation is formed each year. Occasionally, however, the development takes two years (and more?). The moths fly from late May to September, but with a clear focus in the months of June and July. They are crepuscular and fly towards artificial light sources. The females come to the light more often than the males. In the resting position, the wings are placed on top of each other in a steep roof shape and completely cover the abdomen. The mating flight is limited to dusk. The moths are rarely active at other times. The males usually start the flight slightly earlier than the females or almost simultaneously. However, the flight of the males ends before half an hour. After a short take-off flight, the males begin to commute about half a meter above the vegetation. During this pendulum flight, the brush-shaped scent organs are spread out and give off a pheromone to attract the females. The females fly to males from a distance of 25 m, circle them and sit in the vegetation under a pendulous male. The male follows the female into the vegetation and mating occurs. Pairing can take up to two hours. The male hangs upside down on the female, but in the same body orientation as the female, only held by the copulatory organs.

However, after mating , the female flies around intensely. While most other butterfly species attach their eggs to plants, the female of the great hop rootworm sheds the eggs on meadow plants during flight. A total of 200 to 1,600 eggs are distributed in this way, on average around 600 eggs. The egg caterpillars hatch in nature after about 16 to 33 days, on average after about 20 days (or 15 to 20 days). The young caterpillars disappear very quickly into the earth, where they dig a passage lined with silk thread. They begin to feed on soft or woody plant tissue (mostly plant roots ). Over time, they eat their way deeper and deeper into the plant tissue and expand their passages. The larval stage usually lasts a year, but can last two or more years. The caterpillars feed polyphagously on the roots of the following plants:

They can also be found specifically on the following crops:

The caterpillars overwinter (possibly several times) and then pupate in a tubular, elongated cocoon in May and hatch in the following month. Twelve larval stages were formed under largely natural breeding conditions. 315 to 347 days after the hatching of the egg caterpillars, pupation took place in a cocoon at a depth of 12 to 22 cm below the surface of the earth. The puppet rest lasts 21 to 33 days. The pupa is relatively active and moves head end first towards the surface of the earth. Once there, the butterfly hatches after a few days.

Systematics and taxonomy

The species was set up in 1758 by Carl von Linné in the 10th edition of the Systema Naturae under the binomial Phalaena (Noctua) humuli . Currently only two subspecies are mentioned in the literature:

  • Hepialus humuli humuli (Linnaeus), the nominate form , in most of the distribution area and
  • Hepialis humuli thulensis Newman, 1865, Faroe Islands, Shetland and Orkney Islands, the subspecies is usually very contrasting

Leraut (2006) also distinguishes the following formae :

  • f. azuga Pfitzner, 1912. The front wings of the females have a wide pink net pattern
  • f. albida Spuler, 1910. The front wings of the females are light yellow
  • f. martinae Leraut, 2006. The front wings of the females are pink
  • f. metallica Leraut, 2006. The four wings of the males are silver-olive gray.

Harmful effect and hazard

The species is or was considered a pest in meadows and on crops. Even in gardens, root damage on annual and perennial herbaceous plants can cause damage. In the literature, lettuce, strawberries and chrysanthemum cultures are mentioned. In the past, the species was also considered a hop pest. However, the more recent literature denies that the species causes visible damage in meadows. It also "poses no threat to hops."

Due to its frequency in large areas of its area, the species is not considered endangered in Germany. Only in Brandenburg is it rarer and is therefore listed in category 3 (endangered).

Trivia

The “ghostly” flight of the silvery-white males in the twilight over uncut meadows, swinging over one spot, especially when many males have hatched at the same time, has earned this species the name of ghost moth . It has also given this species of moth a certain popularity. The Faroe Islands Post has dedicated a stamp to her.

The great hop rootworm on a Faroe Islands postage stamp

swell

Individual evidence

  1. ↑ Red lists at Science4you
  2. ↑ a b c d e f g h Carter (1984: p. 31/2)
  3. ↑ a b c d Leraut (2006: p. 321/2)
  4. ↑ a b c d e f Speidel in Ebert (Ed.) (1993: pp. 135-138)
  5. ^ Forster & Wohlfahrt (1971: p. 227/8)
  6. ↑ Erich Haeger: 10 years house light capture (Macrolepidoptera). Journal for applied zoology, Duncker & Humblot publishing house, Berlin-Munich, 1956
  7. ↑ Carl von Linné: Systema Naturae 10th edition, Stockholm, 1758 Online at SUB Göttingen ( Memento of the original from 10 June 2008 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. (P. 508) @1@ 2Template: Webachiv / IABot / gdz.sub.uni-goettingen.de

literature

  • David J. Carter: Pest Lepidoptera of Europe with special references to the British Isles. Dr. W. Junk Publishers, Dordrecht 1984, ISBN 90-6193-504-0 .
  • Wolfgang Speidel: Hepialidae. In: Günter Ebert (Ed.): The butterflies of Baden-Württemberg. Volume 3. Moths I (root borer (Hepialidae), wood borer (Cossidae), ram (Zygaenidae), snail moth (Limacodidae), sack bearer (Psychidae), window spot (Thyrididae)). Ulmer Verlag, Stuttgart 1993, ISBN 3-8001-3472-1 , pp. 120-138.
  • Patrice Leraut: Moths of Europe. Volume I. Saturnids, Lasiocampids, Hawkmoths, Tigermoths… NAP Editions 2006, ISBN 2-913688-07-1

Web links

Commons : Big Hop Root Auger  - Album of Pictures, Videos and Audio Files