First findings from Scandinavia and Italy Gas-permeable fault zones and nest sites of red wood ants

Geological findings from Southern Europe to Northern Scandinavia prove that there is a strong affinity of red wood ants (RWA) for tectonically active, gas-permeable faults (Schreiber et al., 2009; Berberich & Schreiber 2013). There are first indications, that ascending geogenic gases from faults play a decisive role. Those gases cause a temperature rise in a restricted area. Formica polyctena is highly sensitive to least rises of temperatures caused by sectoral heating. Dr. Stefan Hetz (Humboldt-Universität Berlin) has proved this in a special experiment set-up. A further aspect could be that in very dry years, cavities within the faults are providing humidity near to the surface, which ants can use.

A more complex relation can be linked to the interaction of gas flow and earth-tides. The gravities of the sun and moon interfere with each other. As a result, periodic maxima of earth-tides (raise of earth crust up to 40 cm, maximum, twice a day), which are multiple of the least one (less centimetres), occur to the crust. These movements have an influence on ascending gases. Ants can possibly record these fluctuations of quantity. In this case, the biological clock of ants has – besides the circadian rhythm and temperature regulation – an additional rhythm. This is advantageous for nest sites with solid blanket of snow. These sites are cut off for any length of time from outer rhythms. This very interesting aspect deserves comprehensive studies by biologists related to the question whether there are other species, which use the rhythm of the earth tides

1. Scandinavia

Recent investigations in Scandinavia (Lake Inari, Oslo Graben) prove an impressive r of faults and red wood ants. Faults, some kilometres long, penetrate the deeply eroded bedrock in the periphery of Lake Inari in Northern Scandinavia

 

Highest nest, built in a trunk of a tree on a NW-SE fault in the south of Lake Inari
 
Herbaceous ant nest in the swamp near Lake Inari. On the other side of the lake, more nests at the lakefront
Numerous nests in the swamp. One Nest in the front on the left side. More nests are distributed in the area of the northern lakefront of Lake Inari.

For there is less or no sediment on the bedrocks, gas can migrate directly from the crust to the surface. Based on the ecological conditions, innumerable nests developed along the fault zones up to the Barents Sea. The nest sites, directly located on the banks of numerous lakes, which can be freezed up to June, are eye-catching.

Ant nest directly located on the bank of Lake Inari

Ant nest at the Lake Retthelltjärn, East of Sundvollen, 40 km North-West of Oslo