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I observed several time an interesting group behavior of Tetramorium : When a scout explore a area that have not been frequented for long time and detect some preys even without catching any , it goes back to the nest ,some time far away, to recruit a more or less coherent group of foragers ( Scouts can recruit also without detecting any food but only in completely unexplored or forgotten area). This recruitment to long unused area when preys are detected and then proximity recruitment to attack individual preys when the density of foragers is enough seems , on a small scale ,to announce the army ant behavior.
Hi Amrik
Nice reports, please keep them coming :)
Well done, the colony looks amazing.
I observed a number of times group attack by ants of different species to kill individual prey to large for one ant to tackle . The recruiter emit a olfactory signal and move about with excitation around the prey or directly to a group of nest mates nearby. So this short distance recruitment to capture a large prey does work only when forager or other old enough workers are nearby and that's apparently true for every ants capable of group hunting . Of the ants I observe Pheidole pallidula was the most capable at this stage, bringing fast a group of workers followed by one or two soldiers in one or two minutes relatively far for such small ants . So the main difference between sorts of ants hunting large preys is their ability to have nest mates ready to be recruited near the prey . Myrmica rubra can recruit to kill a large prey only to about 10 cm around the entrance of their nest. Tetramorium gr.caespitum have a network of foraging gallery , tracks and hiding places radiating from their nest and recruit to slow moving preys until 7 cm from these . Group and mass recruitment to hunting ground may have the effect to bring locally a high density of forager that permit group hunting , in Tetramorium it seems to happen only when recruiting to a new or long time abandoned hunting ground where preys are detected.
update,
The temperature of the room is now a bit more than 20°c at night and the activity and food intake of both colonies start slowing down .
Two samples of Tetramorium sp.e in the US belong to two close genetic lines : One widespread from Armenia to Italy ,the other detected until now only in Romania and the US.
So there is , as far as we know,a good chance that Tetramorium sp.e have been introduce in north America only once or twice from Romania after 1830 with the first direct commercial shipping relations between Romania and the US.
Update,
The temperature in the room is now between 19°c and 22°c but the evaporation of the water in the plaster takes the temperature of the nest down one or two degrees celsius lower.
The food intake of both colonies is now less then half of what it was during summer.
A few days ago about one hundred foragers from the smaller colony brake out and about twenty penetrate the "ant apartment" of the bigger colony and already one or two scouts of this colony had found the way back to the brake out passage to the small colony tank .
I quickly reacted by closing the gap in both tanks anti evasion barrier with oil and capturing the ants on the table. About twenty "Invaders" that did not escape before I closed the gap were killed . The big colony did not seems very alarmed at all and during the fight I did not observed any use of the stinger ,the ants were not very aggressive so it did take hours before all the trespassers were killed. I suspect that the majority of them would have escaped if the passage was not close with oil.
update,
I give permanently Sun flower seeds without husk and only 3 times a week honey , animal food only once a week. The activity and appetite of both colonies have much diminish so the food given attract fewer workers . The food intake is now about 10 times less than in summer. They are now more attracted to diluted honey than to any other food ( but still less than in summer).
i had some these they escaped and i have no idea how - so make sure its good protection . i sell orange woodlice which are high in protein when my colony grows ill be feeding them
Update,
The large Tetramorium colony was ,I suspected , to big for their nests and breakouts were to easy so I purchased a new large framed tank from Antstore with itong vertical nest but the galleries are to large for such small ants and the gallery plan look more as a horizontal nest than a vertical one so I narrowed the galleries with plaster and deepened each chamber with two levels 5 mm high and more than 1cm deep so I triple the horizontal surface usable by the ants .I did make myself a big vertical plaster nest with natural looking galleries most 5mm high and more than 2cm deep so to have a big horizontal surface ( The goal is not to observe in detail but just to keep the ants in best conditions possible wile been able to have a general survey of the colony) . The nests are covered with the new (and better ) red filter.
Then I connected the new tank to the big colony's tank after removing two small acrilik tanks use as foraging arena.
When I removed the dark cover from the two old nests ... surprise. The population of the big colony is even bigger than I expected , probably around 14000 workers , the nest overpopulation was such that the ground was not visible under the ants.
The biggest part of the colony stay in the old nest wile a large number of workers are in the new tank looking for food but mostly adapting the new nests and making galleries in the 2 to 3 mm deep dry sand-loam bottom of the tank .
I stopped to humidifies the old nests and keep it without cover so I expect that the colony is going to move before long .
The day before yesterday I came back late at night from driving one of my children friend home then had a look to the ant nests. A massive column of ants joined the formicarium of the two colonies : The big colony had invaded massively the nest of the smaller one . It was to late to do anything . There were few combats and today I still see some larvae been carried to the big colony nest. The surviving part of the smaller colony is now still defending the small ant farm . I can distinguish the biggest workers of the big colony from those of the other one so I can see the progress of the invasion.
The bigger colony have the advantage of number of workers , about four to one , and about half of its workers are bigger and
stronger , they are also more aggressive.
So I find myself with only one big Tetramorium colony (probably T.sp E or T. moravicum ).
I have the Tetramorium 's since December last year that is eleven months but the big colony had 41 workers so one season old and had full activity until late October so it is the equivalent of a total of three active seasons. We can conclude that the colony of these Tetramorium sp. take about three years to attain 14000 workers from a single founding queen.
It is difficult for me to have the colony in real hibernation but the temperature is now lower at night and the larvae grow seems to have stopped.