Rhynchophorus ferrugineus
| Rhynchophorus ferrugineus | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Rhynchophorus ferrugineus |
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Rhynchophorus ferrugineus | ||||||||||||
| ( Olivier , 1790) |
Rhynchophorus ferrugineus (also red palm weevil ) is a beetle from the family of weevils , subfamily Dryophthorinae . Originally from Asia, it spread almost worldwide in just a few years, including in the Mediterranean area and threatens all palm populations here. Its larva is known as the sago worm and is used locally as a food and therefore an important source of protein.
features
Rhynchophorus ferrugineus is a 3.0 to 3.5 centimeter long weevil. The top of the body, including the pronotum and the wing coverts, is typically predominantly brownish-red in color. Most of the underside and the legs are black, the antennae are also black, but the antenna lobes are reddish. The almost straight, cylindrical trunk is also reddish in color. The antennae are deflected on the sides of the trunk, close to its base. They are kneeled with a greatly elongated base limb (scapus). There are black dots and spots of varying dimensions on the pronotum. The elytra have clear, deeply indented point stripes, they are shortened at the end of the body and leave the last abdominal segment (pygidium) uncovered. The membranous hind wings are normal, the beetles are airworthy and quite good flyers. The pronotum is cylindrical and remarkably elongated.
The species is known for its extremely variable coloration and has distinctive color morphs, which were previously seen as separate species. There are populations whose animals are predominantly black in color and only have a conspicuous, bright red longitudinal stripe on their pronotum.
The larvae, which are called sago worms, have a cream-colored, plump body with finely toothed transverse grooves and a small, hard-shelled and maroon head. On closer inspection, fine hairs can be seen on the body.
distribution
The beetle originally comes from Southeast Asia , where it lives mainly in freshwater swamps. From there it spread through the Middle East to Morocco . Through the import of palm trees, it was brought to Spain , Italy , Greece , France and almost all Mediterranean countries as well as Portugal . It was also found on the Mediterranean islands of Mallorca and Ibiza . There he has now caused millions in damage. Up to March 2013, around 3000 damaged palm trees were counted in Mallorca.
In March 2015, the Mallorca newspaper reported that the pest had now been detected in all communities on the island and had attacked almost 10,000 palm trees since 2006.
According to the state environmental office of Mallorca, as of November 5, 2016, 4% of the palm trees in Mallorca are infested with the pest. That corresponds to around 11,700 palm trees. When the red palm weevil was discovered in the Balearic Islands in 2006, only the Canary Island date palm and the real date palm were infested. Meanwhile, are fan palm , the dwarf palm and even yucca infested by the beetle.
Although the species originates from the tropical latitudes, it survives the winters in more moderate latitudes without problems and can therefore be found anywhere where palm trees grow. The new infection occurs through flying beetles. By shipping infected palms from tree nurseries, they spread across countries and continents.
development
The juvenile stages of the palm weevil are tied to palm trees. The female lays up to 300 eggs individually or in small clutches in crevices or self-eaten cavities in the palm. The larvae hatch after 2 to 5 days. They eat their way through the tissue to the growth zone at the top of the trunk in the area of the leaf base. Other parts of the plant, e.g. B. leaves, fibrous or lignified trunk sections are not permanently attacked. The larval stage lasts one to three months, the larva moults seven to twelve times. It then pupates in an elongated, oval pupal chamber made of plant fibers. After 14 to 21 days, the adult beetles pupation (hatching imagos ). They can be found almost all year round, but in the temperate latitudes they often stay in the pupa chamber until spring.
The infestation is not externally recognizable in the early stages. As soon as symptoms are seen, the tree is usually already hopelessly lost. At the end of an infestation, the leaf fronds die off, and the completely used up and destroyed growth cone can no longer form new leaves.
A large number of different palm species are attacked, including the economically important coconut palms , sago palms , real date palms and silver date palms . In the Mediterranean, the Canary Island date palm, which is often planted as an ornamental tree, is attacked.
First apparent damage to a Canary Island date palm
With the end of the infestation, the crown of the palm is completely destroyed
The palm fronds that have been eaten out at the base fall out of the crown
In the feeding tunnels at the base of the fallen palm fronds there are doll's cradles made of palm fibers
Doll cradles of the red palm weevil.
Opened doll's cradles with adult beetles skinned from the dolls
Canary Island date palm infected with the red palm weevil ( Budva , Montenegro , May 2016)
Canary Island date palm completely destroyed after the red palm weevil infestation (Budva, May 2016)
Traps to attract and destroy red palm weevil (Budva, May 2017)
Rotating soft leaf remnants from the trunk is one way of fighting the red palm weevil (Budva, May 2017)
Treated palm tree that recovers after being attacked by the red palm weevil weevil
Synonyms
- Curculio ferrugineus Olivier, 1790
- Calandra ferruginea Fabricius , 1801
- Rhynchophorus signaticollis Chevrolat , 1882
Surname
In German media, the names Red Palm Weevil , Red Palm Weevil , Indomalay Palm Weevil , Malay Palm Weevil or Palm Weevil can also be found for Rhynchophorus ferrugineus . These are not always common names, so there is a risk of confusion.
The sago worm as an edible insect
The Sagowurm is of indigenous peoples, such as the Korowai of Papua New Guinea or the Kadazan and Melanau on Borneo as food insect used. These live to a large extent on sago palm flour , which they process into a kind of flatbread. The flour of the sago palm is very rich in energy because of its high proportion of starch, but it hardly contains any protein. That is why the sago worms are an important additional source of protein for these people.
In Southeast Asia, sago worms are considered a delicacy. They are eaten raw, smoked, roasted or steamed in tied banana leaves. In Malaysia in particular, sago worms are also prepared in restaurants. The most famous insect dish made from sago worms is called Sago Delight or Kadazan . In Vietnam, some of the larvae are eaten alive with fish sauce.
Individual evidence
- ↑ admin5504: Control of palm weevils . Retrieved on July 6, 2020 (German).
- ↑ Weevil destroys palm trees in the Mediterranean. In: Spiegel Online. January 19, 2008, accessed August 16, 2017 .
- ↑ Praga do escaravelho ameaça palmeiras do Passeio Alegre no Porto. In: O Público. January 10, 2014, accessed August 16, 2017 .
- ↑ La plaga del picudo se desboca. In: Diario de Ibiza. November 16, 2012, accessed August 16, 2017 .
- ↑ El picudo rojo ya afecta a una gran superficie de la Serra. In: Diario de Mallorca. March 4, 2013, accessed August 16, 2017 .
- ↑ Almost 10,000 palm trees on Mallorca attacked by red palm weevils. Queryed in Mallorca Zeitung on March 25, 2015
- ↑ Already four percent of island palms are victims of the palm weevil. In: Mallorca Zeitung from November 6, 2016
- ↑ Fukibo Abe, Kunihiko Hata, Koichi Sone (2009): Life history of the Red Palm Weevil, Rhynchophorus ferrugineus (Coleoptera, Dryophtoridae) in Japan. Florida Entomologist 92 (3): 421-425.
- ^ "Palmenkiller" in Italy ( Memento from February 5, 2008 in the Internet Archive )
- ↑ Rhynchophorus ferrugineus (Olivier 1790). Fauna Europaea, Version 1.3, April 19, 2007, accessed January 20, 2008 .
- ↑ 'Kinh dị' Đuông dừa, đặc sản khó xơi. In: VietnamNet. July 3, 2014, accessed July 19, 2019 .
Web links
- Rhynchophorus ferrugineus (PDF; 52 kB). Leaflet of the Berlin Plant Protection Office, September 24, 2007.
- Center for Invasive Species Research: Rhynchophorus ferrugineus (Red Palm Weevil )
- Control of the palm weevil Rhynchophorus ferrugineus
- redpalmweevil.com (English)