Rhynchophorus ferrugineus

Rhynchophorus ferrugineus

Rhynchophorus ferrugineus is a beetle of the family of Dryophthoridae belonging to the weevils in the broader sense (or weevil -like ) ( superfamily Curculionoidea ). Originally from Asia, it spread within a few years almost worldwide, including in the Mediterranean and threatened here all the stocks of palm trees. Its larva is known as Sagowurm and is used locally as food and an important source of protein.

Features

Rhynchophorus ferrugineus is about 3.0 to 3.5 centimeters long weevil. The top of the body including the pronotum and elytra is typically colored predominantly brownish. The largest part of the underside and the legs are black, and the antennae are black, the sensor leg but turn reddish. Also, the almost straight, cylindrical trunk is reddish in color. The antennas are provided at the sides of the trunk, near, is deflected by the base thereof. They are kneeling with greatly elongated base member ( scape ). Sitting on the pronotum black dots and patches of various expansion. The elytra bear distinct, deeply indented dot stripe, they are truncated at the body end and let the last Hinterleibssegmenzt ( pygidium ) uncovered. The membranous hind wings are formed normally, the beetles are capable of flight and quite good fliers. The pronotum is cylindrical and conspicuously elongated.

The species is known for its extremely variable coloration and has distinct color morphs, which had previously been partially considered separate species. So there are populations whose animals are predominantly black in color and wearing only a striking, bright red longitudinal stripes on the pronotum.

The larvae, called Sagowürmer have a cream-colored, plump body with fine-toothed transverse grooves and a small, hard-shelled and chestnut brown head. A closer look at the body fine hairs can be seen.

Dissemination

The beetle is a native of Southeast Asia, where he lived in freshwater swamps especially. From there it spread through the Middle East to Morocco. He was given the import of palm trees to Spain, Italy, Greece, France and in almost all Mediterranean countries and Portugal introduced. Also on the Mediterranean islands of Mallorca and Ibiza, he has been proven. He has since caused millions in damages. In Mallorca until March 2013 damaged the 3,000 palm trees were counted.

Development

All developmental stages of the species are tied to palm trees. The female lays eggs singly or in small Located in columns or even blown-out cavities at different parts of the palm, a total of about 300 eggs per female. After 2-5 days the larva hatches. The larvae feed from the oviposition site through the tissue until the growth cone (at the root tip, in the area at the neck ) is reached. Other parts of the plant, e.g., Leaves, fibrous or woody stem sections are not affected permanently. The larva molts to depending on the circumstances, from seven to twelve times to until pupation, they needed for one to three months. They then pupate in an elongated oval dolls chamber consisting of plant fibers, within the tribe. After 14 to 21 days pupa hatch, the adult beetles. Beetles are almost all year to make, but avoid in temperate latitudes during the winter months, they then remain until spring as often imagines in the doll chamber. Although the species originates from tropical latitudes, they survived the winter without problems in more temperate latitudes and can happen anywhere, where palm trees are able to grow. Reinfection is done by flying beetles. The remote spread across countries and continents took place, however, due to shipping of infected palm trees in nurseries.

The infestation is virtually not externally visible in the early stages, when symptoms are visible, the tree is usually already hopelessly lost. The beetles usually eat on a tree until the growth cone is completely depleted and destroyed. The tree dies it is because the young leaves die off and no new leaves more can be formed.

Host species are a variety of palm species, including the economically important species of coconut palm, sago palm, date palm True and silver date palm. In the Mediterranean region, as in many other regions, especially the often planted as an ornamental tree Canary Island date palm is particularly strong befressen.

With the end of the infestation, the crown of the palm is completely destroyed

In the food aisles at the base of fallen palm fronds to find dolls cradles made ​​of palm fibers

Doll cradles of the Red Palmrüsslers.

Open Dolls weighing with skinned dolls from the adult beetles

Synonyms

• Curculio ferrugineus Olivier, 1790
• Calandra ferruginea Fabricius, 1801
• Rhynchophorus signaticollis Chevrolat, 1882

Name

In German media found Rhynchophorus ferrugineus for the names of Red Palm Weevil, Red red palm weevil, Indomalaiischer palm weevil, Malay Palmenrüssler or red palm weevil. Not always, it involves common names, so here it is certainly a likelihood of confusion.

The Sagowurm as a protein source

Indigenous peoples like the Korowai in Papua New Guinea or the Kadazan and Melanau in Borneo feed for a good part of sago flour, which they process into a kind of flat bread. Now the flour of the sago palm is due to their high proportion of starch, although very energetic, but it hardly contains proteins. Therefore, set the Sagowürmer for these people an important food supplement dar.

Sagowürmer be raw, smoked, roasted or steamed in banana leaves tied together, eaten. They taste slightly sour cooked and remember the consumption of fried kidneys. Especially in Malaysia Sagowürmer also be prepared in many restaurants. The most famous Sagowürmergericht called Sago Delight or Kadazan.

Swell

• Rhynchophorus ferrugineus (PDF, 52 KB). Leaflet of the plant protection office Berlin, 24 September 2007.
• Palm weevil destroyed the Mediterranean; Spiegel Online science, from January 19, 2008
• " Palm killer" in Italy, courier ( version of 5 February 2008 at the Internet Archive )
• Mallorca soon without palm trees? Comprendes -Mallorca ( 3 December 2010)