Culturally correct song dialects are correlated with male age and female song preferences in wild populations of brown-headed cowbirds

Variation in vocal behavior among local populations of songbirds may be significant to females in mate choice. In a study of dialect populations of brown-headed cowbirds, estradiol-implanted females from two dialects held the pre-copulatory lordosis posture longer in response to playback of the local flight whistle song than to foreign whistle types from adjacent and more distant dialects. Females were held in captivity for a relatively brief period prior to testing and received no tutoring so discrimination was based solely on experience in the wild. This is the first study to show evidence of discrimination by female cowbirds based on flight whistle type. Evidence is presented from one of the study dialects that the majority of yearling male cowbirds are vocally distinct from resident adults in having either foreign or incomplete local whistles. Although these yearlings are fully mature sexually, they have little or no mating success. The correlation between female whistle preference and male mating success suggests that the ability to give the correct local whistle type may be a characteristic used by females to assess age and quality of a potential mate. A learned female preference for the predominant local song type may be a factor in the stability of these dialects by making it adaptive for males to conform to the local dialect.     

Social discrimination tuning in ants: template formation and chemical similarity

To investigate the role of template plasticity in shaping nest-mate recognition processes in ants, we constructed experimental mixed-species groups of Manica rubida with either Myrmica rubra, Tetramorium bicarinatum or Formica selysi. Selecting Ma. rubida as the focal species, we observed the behaviour within mixed-species groups and the transfer rates of cuticular hydrocarbons (CHC) onto the focal ants, and we also tested the aggression of the focal species reared either alone or in association with each of the three different species. We show that Ma. rubida workers were always amicable towards their mixed group members, as towards members of the respective parental colonies, irrespective of the associated species. They did, however, express different levels of aggression towards single-species groups of the other species tested, depending on the species with which they were reared. The study suggests that similarity in CHC profiles in two species leads to a narrow template in mixed groups, while dissimilarity is followed by lower levels of aggression (a broader template), at least against species with similar CHC compound compositions (i.e. both a broader template in the focal ants and familiarity with the compound groups of the tested individuals operate together). This refutes the hypothesis that ants reared in mixed-species groups are systematically more tolerant. It also demonstrates that heterospecific information is not treated equally during development. We suggest that post-imaginal learning, template reforming and decision making are more precisely tuned when the two species' chemical complexes are similar.     

Diversity of Ontogenetic Pathways in Plant Populations

Population heterogeneity in cespitose, fibrous-rooted, brevirhizomatous, stoloniferous, and tap-rooted herbaceous and woody plants is described. This heterogeneity is caused by the multivariant character of plant ontogeny (i.e., its dimensional, morphological, rhythmological, and temporal multiversality), which is regarded as the main adaptation mechanism operating in plant populations because it provides for the diversity of ontogenetic pathways under different ecological conditions.     

Morphophysiological and Population Adaptations ofAjuga reptansL. at the Northern Boundary of Its Range

The results of comprehensive morphophysiological and population studies on Ajuga reptansL., a species of the nemoral floristic complex, at the northern boundary of its range (in the middle taiga subzone of the Komi Republic) are reviewed. Adaptations at the cell, organism, and biocenotic levels are revealed. The maintenance and survival of the species at the boundary of its range are provided for by its physiological plasticity, resistance to low temperatures, and multiple variants of ontogeny. Prognosis of Ajuga reptansfuture status under conditions of global climate change and expansion of anthropogenically disturbed areas is favorable.     

Ontogeny and Population: Developmental Stability and Population Variation

By definition, the ontogenetic and population organization levels are fundamentally different. Studies at these levels are traditionally independent. However, it becomes increasingly evident that special analysis of individuals in terms of ontogeny is necessary for correct estimation of populations and their spatiotemporal dynamics, as well as for understanding the mechanisms of population processes.     

Determining the age of cyclomorphic rodents: Functional-ontogenetic determination,ecological aspects

Functional-ontogenetic determination of age-dependent dental changes (ADCs) in voles has been demonstrated. The relationship between ADCs and the functional state of animals has been analyzed. A scheme and a table for determining individual chronological and biological ages in the bank vole (Clethrionomys glareolus Sch.) are proposed, which markedly improve the accuracy of results. Cases of rodent maturation and breeding in winter are considered.     

Types of Ontogeny and Territorial Distribution of Small Rodents

In small rodents, differences in the average home range size, depending on the type of ontogeny and animal sex, have been revealed. The dynamics of changes in the spatial structure of populations during the breeding season are described.     

Specific Features of the Population Ecology of Creeping Thistle, Cirsium arvense(L.) Scop. s. l.

Two populations of creeping thistle (Cirsium arvense) growing in a field uncultivated for many years and on the sloping bank of an artificial pond were studied with respect to the demographic and chemical composition. The results showed that the contents of some elements in plants depend on specific features of the soil and plant population parameters (abundance, biomass, and ontogenetic composition). Some indices of the content of mineral substances in the population and soil proved to be difficult to interpret unambiguously.     

Population Biology of Cichorium intybus L. (Asteraceae) of the Middle Don River Basin

The stages of ontogeny and morphogenesis of the common chicory were characterized on the basis of long-term observations. A comparative analysis of seed productivity was performed, and the pool of viable seeds in the soil was determined. The ecological–cenotic relationships and the types of population strategy of the species were estimated.     

Specific Features of Mycorrhizal Symbiosis Formation in the Ontogeny of Orchids of the Temperate Zone

The study of relationships between symbiotic fungi and germinating seeds of the Orchidaceae showed that the effect of a fungus on germination depends on the presence of seed dormancy and its pattern. The specificity of symbiosis varies widely. The development of symbiotic sprouts in situand in vitro differs only in the rate, whereas the morphogenesis of asymbiotic sprouts is characterized by several anomalies.