Bivouac (ants)

The bivouac nest or bivouac is a mobile free nest or Soil nests of ants without permanent nest site. Freinister are driver ants ( the subfamily Ecitoninae ) and from the Ponerinen genus Leptogenys. Dorylinae and Aenictinae are erdnistend, but form within the soil nests bivouac -like aggregations. Bivouac nests are conglomerations of workers who cling to each other. Apart from the carcasses no building material is used.

The nest is located near the ground between leaves or in soil or Holzhöhlungen, but also freely between branches hanging nests before coming. At the bivouac nest will spawn and any existing Trophobionten (eg mealybugs ) cling of the bodies of the workers, which are mutually at the Tarsalklauen ( pretarsus ), wrapped protectively. Since the construction of the nest does not require a material, it can be quickly set up and re-dissolved, allowing the mobility of drivers and army ants only. But not only the occasion of walks, even in the day change if workers swarm out, seems to dissolve the nest in the evening to regain volume.

States size

Up to 700,000 workers a bivouac of about 1 m in diameter can populate.

Counts several fist - up child's head large bivouacs of Dolichoderus cuspidatus showed a stock of at least 10,000 herdsmen ant workers, approximately 4000 larvae and pupated ants, about 5000 mealybugs and one ( ie monogyner ) Ergatogyne (ie female worker like Queen ). Male winged ants were observed in large numbers during the dry season ( January-February ) and during the monsoon period ( September-October). Colonies reproduce by division.

Bivouac as a raft

Red fire ants ( Solenopsis invicta ) survive floods by concatenating the individual female and larvae with their bodies to a raft. This raft is a structure that is sturdy and stable enough to carry an entire state on a stream such as the Amazon. It should be noted that the overcoming of water areas for terrestrial insects generally provides a big challenge. The bivouac also called raft acts for the human observer chaotic and consists of a " mat " living body of older workers. On the mat are free to move but in a confined space, with free passage tunnel, the remaining animals. The rafts can accept a diameter up to 45 cm. The buoyancy due to a fact that the body surface of animals consists of a water-repellent cuticle, containing as a main component hydrophobic chitin, on the other hand hold the animal body under water with their Cuticulaborsten air bubbles. From time to time submerged animals must fill their outer air supplies again. Larvae can trap more air bubbles, which is why there are better opportunities for rafts with higher number of larvae. All animals with the air spaces have the same total mass as the entire raft displaced by water. The Raft insensitive to large waves. The rafts can consist exclusively of workers, a questionable strategy for survival. Mostly, they are also home to brood and queens, often symbionts and male ants. It was also observed that male ants were prevented from taking place on the raft. Single ants drown.

The ability to bivouac rafts have several ant species from different continents: Solenopsis germinata (Brazil - Pantanal, Colombia, Venezuela - LLanos ), Solenopsis invicta ( Southern USA), Camponotus compressus (India), Lasius umbratus (England), Myrmica gallienii ( Germany ), Dorylus arcens (West Africa) and possibly more.

Single Documents

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