Knot ants

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Knot ants
Leaf cutter ants Atta cephalotes

Leaf cutter ants Atta cephalotes

Systematics
Class : Insects (Insecta)
Order : Hymenoptera (Hymenoptera)
Subordination : Waist Wasps (Apocrita)
Family : Ants (Formicidae)
Subfamily : Knot ants
Scientific name
Myrmicinae
Lepeletier , 1835

The knot ants (Myrmicinae) are a subfamily within the ants (Formicidae). In addition to the knot ants, the scale ants (Formicinae), the primeval ants (Ponerinae) and the gland ants (Dolichoderinae) are among the widespread groups of ants in Central Europe .

features

Characteristic: physique of a knot ant with two limbs
For comparison: the body of a scale ant with a stalk limb

The special shape of the abdomen is decisive for the German-speaking name of this subfamily . In contrast to the other groups of ants, the stalk of the knot ants consists of two knot-shaped segments ( petiolus and postpetiolus) and is also clearly separated from the following gaster . The stalk member as a movable connection between the breast section and the abdomen is characteristic of all ants. It allows them greater freedom of movement of the abdomen, on the one hand downwards, which allows defense secretions to be sprayed forward, and on the other hand upwards, which is particularly preferred when releasing fragrances. As with the ancient ants , all female castes have a poisonous sting , which can, however, be completely reduced. Larvae always develop into nude dolls.

Glands

The metathoracic gland, a gland present in all ant species that mainly produces fungicidal and bactericidal secretions, contains various acids (e.g. phenylacetic acid and hydroxyhexanoic acid ) that inhibit the growth of undesirable fungi in leaf cutter ants . In addition, substances that promote the growth of the desired fungus are formed in this gland.

Various glands produce secretions only in very small quantities. As pheromones, these can be useful for communication. The knot ant Solenopsis richteri is an extreme case , the pheromone of which is used to mark the path, even in the smallest dilutions. Only in the genus Crematogaster is there a tibial gland on the legs , which also produces pheromones .

Larval development

In the case of the knot ants, it is possible that larvae overwinter in the mother's nest; for certain species even two years. This is usually not possible with ants, as the development of the early stages takes place too quickly and the larvae would hatch in winter and then freeze to death or starve to death, since all brood carers, like all other ants, are frozen in winter. The knot ants feed their larvae, which hatched shortly before hibernation, with a substance that can greatly delay and slow down the development of the larvae. In the spring these larvae are fed normally. Due to the long development time, only queens are created. It is not known what the reason is. There are only as many larvae fed as the state needs queens, since there are usually too many overwintered larvae. After a certain time, all larvae are fed this development-retarding food.

distribution

The best-known representatives in Central Europe are the great knot ant ( Manica rubida ), the red garden ant ( Myrmica rubra ) and the dry grass knot ant ( Myrmica scabrinodis ). Many genera of the knot ants occur only in the tropical and subtropical areas, including the leaf cutter ants (genera Atta and Acromyrmex ), which are also restricted to the two American continents. The leaf cutter ants do not feed on the leaves from which they cut pieces, but just chew them up and use them as a substrate for a special mushroom culture that serves their diet.

The pharaoh ant ( Monomorium pharaonis ) was introduced to Central Europe from the tropics and subtropics . Although this is very sensitive to temperature and dies at 0 ° C, it has adapted to life in heated buildings. The settlement can take place through the formation of branches.

Systematics

The knot ants are represented worldwide with over 6,000 species and thus make up about half of all known ant species. They are subdivided into the following tribes and genres (selection):

swell

Individual evidence

  1. ↑ Bernhard Seifert : The ants of Central and Northern Europe . lutra Verlags- und Vertriebsgesellschaft, Görlitz / Tauer 2007, ISBN 978-3-936412-03-1
  2. ↑ Heiko Bellmann : bees, wasps, ants. Hymenoptera of Central Europe . Franckh-Kosmos, Stuttgart 1995, ISBN 3-440-09690-4
  3. ↑ Myrmicinae Taxon Count. (No longer available online.) Hymenoptera Name Server, formerly the original ; Retrieved June 16, 2008 .  ( Page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.@1@ 2Template: Dead Link / atbi.biosci.ohio-state.edu  
  4. ↑ Myrmicinae. Tree Of Life web project, accessed May 30, 2008 .

literature

Web links

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