Comparative analysis of optional hunting behavior in Cricetinae hamsters using the data compression approach.

Research into the hunting behavior in members of the Cricetidae family offers an opportunity to reveal what changes in the predatory behavioral sequences occur when a rodent species shifts from an omnivorous to a predatory lifestyle. The study tests the following hypotheses: are there phylogenetic differences in the divergence of species' predatory lifestyles in hamsters or do ecological factors lead to shaping their hunting behavior? We applied the data compression approach for performing comparative analysis of hunting patterns as biological "texts." The study presents a comparative analysis of hunting behaviors in five Cricetinae species, focusing on the new data obtained for the desert hamster Phodopus roborovskii whose behavior has never been studied before. The hunting behavior of P. roborovskii appeared to be the most variable one. In contrast, behavioral sequences in P. campbelli and Allocricetulus curtatus display more significant order and predictability of behavior during hunting. Optional hunting behavior in the most ancient species P. roborovskii displayed similarities with obligate patterns in "young" Allocricetulus species. It thus turned out to be the most advanced hunter among members of the Phodopus genus. Differences in hunting sequences among Phodopus representatives suggest that the hunting behavior of these species, despite its optional mode, was subject to selection during species splitting within the genus. These results did not reveal the role played by phylogenetic differences in the divergence of species' predatory lifestyles. They suggested that ecological conditions are the main factors in speciation of the hunting behavior in hamsters.

[Yeast Communities of Formica aquilonia Colonies].

Yeast abundance and species diversity in the colonies of Formica aquilonia ants in birch-pine forbs forest, Novosibirsk oblast, Russia, was studied. The average yeast number in the anthill material was 10³-104CFU/g, reaching 105 CFU/g in the hatching chambers. Typical litter species (Trichosporon monilfiforme and Cystofilobasidium capitatum) were predominant in soil and litter around the anthills. Apart from these species, ascomycete species of the family Debaryomycetaceae, Debaryomyces hansenii and Schwanniomyces vanrijiae, were predominant in the anthill material. Yeast population of the ants consisted exclusively of the members of these two species. Thus, highly specific yeast communities formed in the colonies of Formica aquilonia ants differ from the communities of surrounding soil. These differences are an instance of environment-forming activity of the ants.

[Spatio-ethological aspects of interactions between small mammals and wood ants].

Mechanisms of interactions between species present one of the central problems of contemporary behavioral and evolutionary ecology. Field observations of possible resource redistribution and mutual behavioral adaptations between representatives of different guilds with substantially overlapping niche parameters are, so far, few. Using the methods of small mammals censuring, with account for their mobility and burrowing activity, at the sites with high and low dynamical density of wood ants Formica aquilonia, as well as in anthills proper, spatial interactions between these animals are revealed for the first time which are based on seasonal transformations of topic competition and synoecism. Species composition and domination structure of small mammals communities appear to be similar in those territories controlled by F. aquilonia and almost free of them. However, judging by animals' spatial distribution and activity it can be suggested that wood ants, being a disturbing factor, markedly reduce the numbers and burrowing activity of small mammals in their territory and, apparently, hinder mammals dispersion. During seasonal resting of ants, when they move down into the soil, anthills attract a lot of small animals: from October to May up to 84% ant nests are burrowed by murine rodents and insectivore mammals. It seems to be possible that there are trophic relationships between small mammals and wood ants, with mammals consuming nest substrate as well as insects themselves.

[Possible evolutionary mechanisms of 'culture' in animals: The hypothesis of distributed social learning].

There is a plethora of works on the origin and genesis of behavioral traditions in different animal species. Nevertheless, it still remains unclear as for which factors facilitate and which factors hinder the spreading those forms of behavior that are new for a population. Here, we present an analytical review on the topic, considering also the results of studies on 'culture' in animals and analyzing contradictions that arise when attempting to clarify the ethological mechanisms of cultural succession. The hypothesis of 'distributed social learning' is formulated, meaning that for spreading of complex behavioral stereotypes in a population the presence of few carriers of consistent stereotypes is enough under the condition that the rest of animals carry incomplete genetic programmes that start up these stereotypes. Existence of 'dormant' fragments of such programmes determines an inborn predisposition of their bearer to perform a certain sequence of acts. To complete the consistent stereotype, the simplest forms of social learning ('social alleviation') turn to be enough. The hypothesis is examined at the behavioral level and supported by experimental data obtained when studying the scenarios of hunting behavior development in ants Myrmica rubra L. It makes possible to explain the spreading of behavioral models in animal communities in a simpler way than cultural succession.

Experimental study of cognitive aspects of ambivalent foraging as exemplified by the great tit.

A hypothesis of ambivalent foraging is proposed based on ideas about dual treating of the prey by a consumer: the food value attracts while the danger repulses. The foraging strategy of the great tit was investigated experimentally with the use of artificial "food patches" with variable amounts of dangerous prey (live red wood ants) and non-dangerous prey (fly larvae). With non-dangerous prey, the behavior of the birds corresponded to the known marginal value theorem: they proceeded with foraging until the resources were exhausted. We found the threshold amount of dangerous prey that prevents tits from hunting.

[Behavioral mechanisms of spatial competition between red wood ants (Formica aquilonia) and ground beetles (Carabidae)].

Behavioral aspects of spatial competition between red wood ants (Formica aquilonia) and six mass species of Carabidae were studied in field and laboratory experiments. We showed that red wood ants essentially influence spatial distribution of ground beetles on their common territories. Transplantation experiments suggest that in newly established ants' settlements stronger forms of interrelations arise than in old stable colony. To examine the ability of beetles to avoid collisions with ants we used two experimental techniques. In laboratory, we tested carabids ability to avoid a clash in a Y-shaped labyrinth containing an active tethered ant in one section. In field experiments we compared quantitative characteristics of movements (such as crookedness of individual trajectories, speed of movement, the time spent on stops) for beetles placed close to ants foraging routes and on ant-free plots. All beetles studied displayed a clear tendency to learn, that is, to modity their behavior in order to avoid collisions with ants. Species that exhibited best parameters of learning were closer to ants by their size and characteristic movement, namely, Pterostichus oblogopunctatus and P. magus. Beetles' stereotyped behavioral tactics can be considered universal for avoiding collisions with any subject (for instance, with an ant) of a certain size and speed of movements. A set of tactics in the labyrinth included: (1) attempts to round the ant; (2) turns away after touching the ant with antennae; (3) turns away without a contact; (4) avoidances of a dangerous section; (5) stops near the ant with the antennae hidden. Comparing pairwise difference between four species shows that beetles use species-specific preference for definite combinations of tactics. Effective learning allows carabids to penetrate into ant foraging territory and partly avoide interference competition. It seems that red wood ants are not inclined to learn to avoid collisions with competing carabid species. Instead, they recognize an "enemy's image" and selectively attack relatively small predatory carabids rather than herbivorous species. Experiments with dummy beetles suggest that ants react for several hierarchically organized key characteristics of competitors such as speed of movement, dark color, bilateral symmetry, protuberances (legs, antennae), and smell. Among "professional" groups in ant family, guards and hunters react to beetles aggressively, whereas aphid tenders ignore them. Sophisticated combination of flexible and innate behavioral patterns enables insects to share territories and interact in the mode of relatively mild, spatial, competition instead of predation. Eliciting sets of hierarchically organized features of competitors that govern adjustment of spatial distribution in insects' community enable us to integrate ideas of classic and cognitive ethology.

[The study of tool use as the way for general estimation of cognitive abilities in animals].

Investigation of tool use is an effective way to determine cognitive abilities of animals. This approach raises hypotheses, which delineate limits of animal's competence in understanding of objects properties and interrelations and the influence of individual and social experience on their behaviour. On the basis of brief review of different models of manipulation with objects and tools manufacturing (detaching, subtracting and reshaping) by various animals (from elephants to ants) in natural conditions the experimental data concerning tool usage was considered. Tool behaviour of anumals could be observed rarely and its distribution among different taxons is rather odd. Recent studies have revealed that some species (for instance, bonobos and tamarins) which didn't manipulate tools in wild life appears to be an advanced tool users and even manufacturers in laboratory. Experimental studies of animals tool use include investigation of their ability to use objects physical properties, to categorize objects involved in tool activity by its functional properties, to take forces affecting objects into account, as well as their capacity of planning their actions. The crucial question is whether animals can abstract general principles of relations between objects regardless of the exact circumstances, or they develop specific associations between concerete things and situations. Effectiveness of laboratory methods is estimated in the review basing on comparative studies of tool behaviour, such as "support problem", "stick problem", "tube- and tube-trap problem", and "reserve tube problem". Levels of social learning, the role of imprinting, and species-specific predisposition to formation of specific domains are discussed. Experimental investigation of tool use allows estimation of the individuals' intelligence in populations. A hypothesis suggesting that strong predisposition to formation of specific associations can serve as a driving force and at the same time as obstacle to animals' activity is discussed. In several "technically gifted" species (such as woodpecker finches, New Caledonian crows, and chimpanzees) tool use seems to be guided by a rapid process of trial and error learning. Individuals that are predisposed to learn specific connections do this too quickly and thus become enslaved by stereotypic solutions of raising problems.

[Social learning in animals: comparative analysis of different forms and levels]. / Sravnitel'nyi analiz razlichnykh form sotsial'nogo obucheniia u zhivotnykh.

Social learning as one of the key concepts of cognitive ecology includes different forms of behavioural displays from relatively simple, such as "social release" and "stimulus enhancement" up to "teaching" and "cultural transmission" in animal communities. Rapid development of this fields resulted in some contradictions in methods and terminology. In this review different forms and levels of social learning are analyzed. Ecological aspects of social learning are connected with diet shaping, fear of predators and mate choice. The first aspect is the most studied but still discussible. Social learning being an intricate component of feeding behaviour matches with innate behaviour, imprinting as well as early associative learning. Investigation of cognitive aspects of social learning going back to Thorndike's crucial question "Do apes ape?" are now developing into series of questions including even: "Do ants ape?". Elaboration of universal methods of comparative studying of social learning such as "artificial fruit" and "two ways/one outcome" has essentially enlightened these questions and made comparative analysis possible. Large continuum of displays of cognitive skills in social learning has been revealed in non-primate species. One of the discussible issues in the role of social learning is distribution of innovations. Many authors have investigated this intriguing aspect of animal behaviour in different ways, such as long field observations as well as laboratory experiments based on "artificial innovators" that is specimens specially taught by experimentalists. Many impressive results were obtained; in particular it turned out in contradiction with some mathematical models that individuals in groups are rather different in their psychophysiological predisposition to innovative behaviour. Role of teaching in such different forms of behaviour as shaping of species-specific behavioural patterns and spread of innovations is considered. Although the majority of animals in wild populations are not good teachers and pupils, some cultural aspects of behaviour were recently revealed, mostly in primates. At the same time some classical results concerning cultural transmission of new patterns (for example, bottle-opening in tits) were experimentally revised. Many problems still remain unsolved, in particular, how spread of innovations may favour prosperity of populations; to what degree behavioural peculiarities of local groups may be determined by processes of social learning; which internal and external factors and under what circumstances invest into social learning in natural environment.

[Experimental studies of the capacity of ants for the addition and subtraction of small numbers]. / Eksperimental'nye issledovaniia sposobnosti murav'ev k slozhenii i vychitaniiu nebol'shikh chisel.

In the laboratory experiments Formica polyctena ants had to transmit the information about the position of a "branch" situated on a long "trunk". Each branch ended in an empty trough, save one filled with syrup. The food was placed on different branches with different frequencies; on the preliminary chosen special branches the troughs were filled substantially more frequently than on the others. For example, in 1993 we chose two special branches, nos. 10 and 20, on which the food was placed with a probability of 1/3, while for any of the other 28 branches the probability was 1/84. When the ants had learnt this, they changed the way of information transmission about the coordinates of the branch containing food and spent less time to transmit the messages about branches nos. 10 or 20. Careful analysis of time required for transmitting messages about trough coordinates suggests that ants "present" the number of a branch in a way similar to that for the Roman figures, and the "special" numbers (10 and 20 in the case) have the same significance as the basic Roman figures V, X, L, etc. Thus, the ants seem to be able, first, to put the duration of a message into agreement with its frequency and, second, to add and subtract small numbers, as people do when use the Roman figures.

[The transfer of information about the quantitative characteristics of an object in ants]. / Peredacha informatsii o kolichestvennykh kharakteristik ob''ekta u murav'ev.

In the laboratory experiments devised on the basis of the Information Theory, ants (Formica polyctena Foerst.) had to transmit definite information on the number and coordinates of objects. One of the experimental sets consisted of a long "trunk" with branches ended in an empty trough, except for one filled with sugared water. Another set consisted of the lattice which simulated Cartesian coordinates. Ants had to learn position of the through and transmit its coordinate on the lattice. Obtained results suggest ants as being able to estimate the number of objects and transmit this information to their nest mates as well as the information on the coordinates of objects.