J Dobrzański’s research while affiliated with Nencki Institute of Experimental Biology and other places

The paper contains a polemic with the view expressed by Talbot, Wilson and Topoff and his co-workers, who maintain that the existence of scouts and their leading directing in slave-raids of the American Polyergus' species is fully proved. In particular we do not agree with Talbot's and Wilson's argument that following by the amazons of the scent-trail prepared from the crushed bodies of their nestmates indicates that the amazon raids follow the trails of scouts. Considering the results and notions of the above-mentioned authors, we maintain that the mechanism of slave-raids in the American amazons is far from clear.

Formica cinerea ants are the species digging their nests in the ground, so they never handle thicker building materials. Under conditions unfavorable to their normal existence, brought about by several years of continued meteorological disturbances, one colony of ants established itself in an atypical and unique in this species mound-shaped nest, similar to the nests of the hill-building species of Formica. On the basis of observations of individual building workers it was determined that most of the F. cinerea ants failed, during the whole summer, to achieve improvement in the technique of carrying building material. Moreover, they all used to drop it loosely, which is done only by the naive individuals of the hill-building species of Formica. It is suggested that the deficiency in manipulatory learning in F. cinerea is due to the lack of hereditary elements of hill-building behavior.

A new hypothesis concerning the mechanism of the P. rufescens' slave-raids, is proposed. (i) The so-called pseudo-scouting does not contribute to the slave-raids. (ii) The direction of the raid is determined by the random movement of the most easily aroused individuals - the so-called activists. (iii) Once the direction has been set the army marches straight ahead and returns by the same road orienting itself by visual stimuli; single individuals who lag behind can however follow the scent-trial which had been left by the army. (iv) The slave-capturing instinct of the amazons is not directed at the abduction of pupae alone but also and even perhaps primarily at the abduction of mature individuals belonging to the slave-species; that the amazons bring almost only pupae is caused by the fact that the mature individuals offer resistance and are consequently a more troublesome prey.

The foraging territory is not divided among particular foragers, at least in the young, small families of M. laevinodis. The same individuals may be observed repeatedly only at the aphides over a period of several days, which may be explained by a transient memorizing of the source of attractive food. Along with the faculty of these ants to inform their nestmates of the food source, a certain continuity in care of the aphides is ensured. Various forms of behavior among particular foragers coming in contact with the trophy exceeding their strength were noted. The less time the ant hesitates before to the nest, the sooner and more efficiently it recruits helpers and the smaller is its dependence on its own odor trails when moving on the terrain. Since there exist transitory forms between diametrically opposite manifestations of such behavior, possibly the process of individual acquirement of capabilities necessary for fulfilling foraging function occurs.

The structure of relationships between the neighboring species of ants is characterized by great variability. What happens when particular individuals meet - depends upon considerable differences between individual behaviors of ants and a number of variable factors determining the actual emotional state of the workers. From these factors, it is the general structure of forces between the nests that changes slowest, and may be responsible for reaching temporary stabilization of the interspecific relationships. Invariable hierarchical structure between the species occurs very rarely: when there is an enormous supremacy of one of the species.

Carrying heavy objects is a common element in the foraging and building behavior of ants. The initial stages of this behavior, i.e., lifting and moving in T. caespitum displayed as stereotyped patterns of movement. These patterns do not improve as the ants become older and more experienced, which suggest their congenital nature. Growing experience of ants is manifested in the later stages of the transportation of heavy objects, and especially in entering the correct opening of the nest with the carried prey. When a foraging ant leaves its nest to return to the prey it initially moves in the general direction of its objective. It is not until a certain distance from the nest is reached, that the ant is able to use olfactory stimuli to locate and follow its previous path. These observations indicate that the representatives of this species do not learn an exact way to and from the nest but instead have a memory for direction. The congenital character of these basic elements of foraging and building behavior allows the existence of a social organization without a division of work and foraging areas.