Tobacco beetle
| Tobacco beetle | ||||||||||||
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Tobacco beetle ( Lasioderma serricorne ) |
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| Scientific name | ||||||||||||
| Lasioderma serricorne | ||||||||||||
| ( Fabricius , 1792) |
The tobacco beetle ( Lasioderma serricorne ) is a beetle from the rodent beetle family (Ptinidae). The species occurs in stored tobacco products and is, besides the bread beetle ( Stegobium paniceum ), the only known species of rodent beetle that can also be found in stored food. Because of these food preferences , the species is considered a pest that has been with humans for a long time. Tobacco beetles have even been found in the dried raisins of Tutankhamun's tomb .
features
The beetles are 2 to 2.7 millimeters long and have a reddish-brown, rounded, oval-shaped body. When viewed from above, your head is often covered by the pronotum . The wings (elytres) are covered with fine hairs. The species is very similar to the bread beetle, but can be easily distinguished from it. The antennae of the tobacco beetle are toothed, whereas those of the similar species are imperforate and end in a three-part club. In addition, the wings of the bread beetle have rows of pits, making the wings appear lined, whereas the wings of the tobacco beetles are smooth.
Older larvae are white and hairy and resemble white grubs . The larvae of the bread beetle also look similar to those of the tobacco beetle, but those of the latter have longer hair, their head is evenly rounded dorsally and they have a dark spot on the head capsule with a convex edge that extends to about half the height of the fron. They also have a Arolium which centered under the claws of the tarsi emerges.
distribution and habitat
The species is distributed pantropically, but can be found anywhere worldwide due to human trade. In the less warm regions of the world, such as in Central Europe, it only occurs in warm human surroundings and cannot survive winter outdoors. The species is common everywhere and occurs particularly where dried tobacco products such as leaves, cigars, cigarettes or chewing tobacco are stored. They prefer to inhabit dark to semi-dark cracks, corners or crevices.
Way of life
When disturbed, the beetles often retract their legs and pull their heads far down under the pronotum, so as to be balled and motionless to wait. In the light, the beetles are very active and quick to fly, probably to find a suitable dark hiding place as quickly as possible. They are mainly crepuscular, but they show activity all night long. Adults stop eating but drink fluids.
The life cycle of the tobacco beetle is strongly dependent on the level of the ambient temperature and the source of food found and usually lasts between 40 and 90 days. Documented extreme values are 26 days at 37 ° C and 120 days at 20 ° C. The females lay 10 to 100 eggs directly in the food substrate. The larvae hatch after 6 to 10 days and then go through four to six larval stages in five to 10 weeks. To pupate, the larvae dig cells into the food substrate or build a protective cocoon out of food and other small parts. The cocoons are often grown on solid material. If the infestation is severe, they form large clumps. The puppet rest is one to three weeks. The adult beetles have a life expectancy of one to four weeks. Under ideal conditions, five to six overlapping generations can be formed per year. From a temperature of 17 ° C, the development of the animals is impaired and adults die if they are exposed to temperatures of a maximum of 4 ° C for six days.
Economical meaning
The species is considered to be the most economically important pest on tobacco products. In addition, it is just as great a pest on numerous foods, such as flour, dried fruits such as dates and raisins, cereals, cocoa, coffee beans, spices and herbs, nuts, rice, dry animal food and other foods that have been in for a long time Storage cupboards, chambers and the like are stored. The beetles can also be found on dried plants, for example in herbaria, decorations and potpourris , in medicines, on insect preparations , in the filling material of furniture, paper mache and in the binding glue of books. Tobacco beetles have yeasts as symbionts that produce vitamin B. The yeasts get onto the eggs when they are laid in the oviduct of the females and are then ingested by the larvae during hatching. With the help of these yeasts it is possible for the beetles to feed on substances that are very poor in nutrients.
The beetles' feeding causes direct damage to the respective substrates, which are contaminated by excretions, pegs, but also the animals and their remains themselves. Indirect damage occurs when the imagines eat or eat through packaging material. The larvae do this in their search for a suitable place to pupate.
Combat
The control and avoidance of tobacco beetle infestation at home is relatively easy, so that the use of insecticides is only necessary in extreme cases. Infested food must be found and disposed of; all food must be examined and safely stored in jars with screw caps. It is also important to thoroughly remove any leftover food, such as flour and crumbs. Suspicious foods can be treated to kill all stages by storage for 16 days at 3 ° C or 7 days at −4 ° C or by heating above 88 ° C for one hour, or above 49 ° C for 16 to 24 hours.
In the commercial sector, where the animals are harmful in particular in flour mills, bakeries and other food-producing companies, as well as storage of these products, the tobacco beetle was previously fought primarily by fumigation, for example with the now banned bromomethane . Although the complete and sufficient increase in temperature over longer periods of time is also used for control, insecticides, such as methoprene in tobacco products, are also used. The Biological control by parasitoids is hardly relevant, since not usually prevents the contamination of products, but is even reinforced by the employed insects. Infestation control is carried out using pheromone traps.
Natural enemies
The predators of the tobacco beetles include black beetles of the genus Tenebriodes , colored beetles of the genus Thaneroclerus and various ground beetles . The eggs are eaten by predatory mites. Parasitoids that attack the beetles are known from the ore wasp families Pteromalidae and Eurytomidae as well as from the flat wasp family (Bethylidae; superfamily Chrysidoidea ).
Synonyms
- Ptinus serricorne Fabricius, 1792
- Xyletinus brevis Wollaston, 1861
- Lasioderma castaneum Melsheimer, 1845
- Lasioderma testaceum Stephens, 1835
- Ptilinus testaceus Duftschmid, 1825
supporting documents
Individual evidence
- ↑ a b c d e f g h i j k l m Featured Creature: cigarette beetle, Lasioderma serricorne . University of Florida - IFAS, accessed May 21, 2014 .
- ^ A b c d Karl Wilhelm Harde , František Severa : Der Kosmos-Käferführer. The Central European beetle . Franckh-Kosmos, Stuttgart 2000, ISBN 3-440-06959-1 , p. 230 .
- ↑ a b c d e Thyreocoridae. Fauna Europaea, accessed May 21, 2014 .
