Formica sanguinea

Worker from the Crimson robbery ant ( Formica sanguinea )

The Crimson predatory ant ( Formica sanguinea ) of the subfamily of ants scales ( Formicinae ) belongs to the genus of wood ants (Formica ) and there to the sub-genre of predatory ants ( Raptiformica ).

Features

Head, mesosoma, Stielchenglied and legs are light to dark red, the gaster is black, the back of the head is often dark. Mostly missing the black spots on pronotum and mesonotum. The mandibles, cheeks and forehead are largely hairless angedunkelt dark brown or only slightly. The strikingly large compound eyes are hairless. The most important distinguishing feature for Raptiformica species is considered a deep curved indentation at the anterior margin of the head shield ( clypeus ). The body length of the workers is six to nine millimeters. The queens are nine to eleven millimeters, the males seven to ten millimeters long. The reproductives swarm from June to August.

Distribution and habitat

The Crimson predatory ant is widespread throughout Europe and is used in some areas very often. It prefers dry habitats along the woods or in clearings, but also settled in the open field on a dry grass, and sometimes can even be found in man-made structures such as old barns or woodshed.

Way of life

The species belongs to the slave-holding ants. From mid-June to mid-August attacked the workers the nest of another Formica - type to rob their larvae and pupae. These stages of development, primarily dolls are transported into his own nest and there either recycled as food or bred as slaves. The slave ants, which are also referred to as auxiliary ants, most work will be executed within the nest and are rarely involved in the search for food or predation. Never, there are males or fertile females of the slave ants in captivity.

The Crimson predatory ant acts not as efficient as specialized slave-hunters, such as the Amazon ants in their raids by far. For this, they can completely exist without slaves and after colony founding in no way dependent on this. They are therefore called a " voluntary slave hunters ".

The colony founding in Formica sanguinea is done by temporary social parasitism in Formica species of the subgenus Serviformica or by adoption in conspecific colonies and twig nest formation.

The workers are based in the field mainly through visual impressions, whereas pheromone trails only play a subordinate role. Among all ants have this type, in addition to Formica rufa, of the best-developed compound eyes with the highest number of photoreceptor cells ( ommatidia ) and the best resolution. Most ommatidia have the males, in which also the Sehlappen ( optic lobes ) accounts for a share of 60 percent of the insect brain. In Queens, there are 40 percent and 35 percent of the workers.

Symbiosis with tufts beetles

The tufts beetles (family rove beetles ) of the genera Lomechusa and Atemeles are breeding predators in the ant nests and still be tolerated by the ants yes sometimes even fed. This behavior is due to the greed of the ants after elimination of the tufts beetles. This excretion is not a waste product of the bunch beetles and studies have shown that it is not is a food for the young but clearly an alcohol-like drug for the ants. For this drug, the ants also take a partial loss of breeding out without the tufts beetle attack. It has already been observed, the first brood of the tufts beetles bring ants from danger after their own brood. It is believed that the behavior of the predatory blood-red ant prey used by tufts beetles to compensate for the loss of breeding.

If excessive proliferation of the tufts beetle in an ant colony leads the ongoing breeding and feeding loss to the extinction of the colony. Some biologists have suggested that the blood red ant prey probably would have been exterminated by the tuft of beetles, when the brood carers of ants would not spend the tufts beetle pupae to dry and warm storage locations, just like the ant pupae. However, the tufts beetle pupae tolerate this climate is very bad.

Nutrition

The food of Formica sanguinea consists mainly of honeydew and insects, other sweet juices (such as nectar or tree sap ) and plant seeds ( elaiosomes ) are taken.

Nesting

The nests are usually applied in the protection of rocks or in lying deadwood. Although this species is considered one of the " mound-building wood ants " arise only sometimes mounds, such as at the Red Wood Ant. These are then also much flatter.

Endangering

The Crimson predatory ant is on the Red List of Germany as not at risk.

Swell

• Dieter Otto: The Red wood ants. ( 3rd revised and expanded edition. ) Westarp Sciences 2005, ISBN 3-89432718-9
• Bernhard Seifert: The ants of Central and Northern Europe. Lutra, Görlitz / Tauer 2007, ISBN 978-3-936412-03-1
• Heiko Bellmann: bees, wasps, ants. Hymenoptera of Central Europe. Franckh-Kosmos, Stuttgart 1995, ISBN 3-440-09690-4
• Wolfgang Schwenke: Ants of fragrant steered state. Country -Verlag, Hannover 1996, ISBN 3-7842-0309-4