Geographic Variation in the Seasonal Reproductive Strategy of the Mite Varroa jacobsoni in the Honeybee Nest

Variation in the reproduction of Varroa jacobsoni mite was studied in relation to the expansion of the range of its parasitism on the honeybee. Geographic differences in the seasonal dynamics of mite reproduction in the nests of bee families were revealed. Variation in the sex ratio of mites and the factors inhibiting their reproduction at the northern boundary of the honeybee range are considered. The forms of parthenogenetic reproduction in V. jacobsoni are discussed.     

Competition between Populations in the Consumer–Producer Trophic Chain in a Closed Aquatic System

The functioning of a closed aquatic consumer–producer system with spatially separated links, with each link consisting of two species, is considered. Competition between the consumers (infusorians Paramecium caudatum and rotifers Brachionus sp.) feeding on a mixed algal culture (Chlorella vulgaris and Scenedesmus sp.) and competition between these algae under conditions of limited nitrogen supply are analyzed. It is shown that Scenedesmus algae have an advantage over C. vulgaris in terms of competitiveness, and their metabolic products have an adverse effect on reproduction in infusorians.     

Influence of silts on the growth,reproduction and chlorophyll fluorescence of <Emphasis Type="Italic">Potamogeton crispus</Emphasis> in turbid water

Turions of Potamogeton crispus were planted in several turbid waters. Some parameters of growth, reproduction and chlorophyll fluorescence were measured. The results were as follows: (1) Sprouting rates in all groups reached to 100.0% on the 17^th day. (2) The parameters of the growth (stem and leaf) and chlorophyll fluorescence (Φ_PSII, qP and qN) in 120 and 150NTU waters were inhibited heavily 60 days later, and their survival time was only 140 days. However, the plants in 30 to 90NTU waters could grow near water surface, their survival time was about 190 days. (3) After 150 days, the saturating irradiance intensity and rETR_max of the leaves in 30 to 90NTU waters markedly decreased with an increase in the amount of attached silts, and the number and fresh mass of turions (propagula) in 60 and 90NTU waters were significantly lower than the control. In summary, P. crispus in 0.7-metre-deep turbid water with suspended silts (not more than 90NTU) could sprout and grow normally, and produce the turions.     

The effect of passive smoking on pulmonary function in children

A study of ventilatory function was conducted in 344 nuclear families in a representative community population sample in Tucson, AZ. Household aggregation of pulmonary function, which is dependent on household aggregation of body mass, might affect the relationship of children's pulmonary function to parental smoking. When household aggregation of body mass was taken into account, there was no relationship of children's pulmonary function values to parental smoking. The trend, in the opposite direction, was similar to that found by Speizer et al. (1980a), but was not significant in this study. It must be concluded that passive smoking in the family, usually due to parental smoking habits, does not seriously affect permanent markers of respiratory disease such as pulmonary function.     

Double-brooded great tits (<Emphasis Type="Italic">Parus major</Emphasis>) in Mediterranean oak habitats: Do first broods always perform better than second broods?

Although mistimed reproduction (i.e., time-lag between peak food supply and offspring food demand) has been attributed to habitat modifications or climate change in recent avian investigations, earlier breeding parents have higher reproductive success in many habitats. Here we compare first and second broods in great tits (Parus major L.) from two Mediterranean oak habitats differing significantly in the timing (about 5 weeks), but not the amount of caterpillar supply required to rear chicks. The study indicates that both the extent of mistimed reproduction and the breeding date per se influence breeding performance in this study system. The text was submitted by the authors in English.     

Risks of global warming on montane and subalpine forests in Switzerland – a modeling study

In this study, we assess the risks of global warming on distributions of individual tree species in Switzerland. Applying a spatially explicit model, tree occurrence is predicted as a function of high resolution and physiologically relevant biophysical variables. The study shows that warming only slightly alters the overall abundance of tree species. However, the preferred temperature regimes are unevenly distributed along an elevational gradient, and the sensitivity to temperature varies considerably between the species. As a result, major reorganizations of forests in montane and subalpine belts are expected, i.e., a segregation of the core distributions of Fagus sylvatica and Picea abies is observed. Tree distribution potentials near timberlines, however, remain roughly the same. Electronic Publication     

Assessment of Present-Day Reproduction Efficiency in Stellate Sturgeon Acipenser stellatus in Different Spawning Zones of the Lower Volga

Studies performed from 1979 to 1998 provided data on the efficiency of natural reproduction of the stellate sturgeon Acipenser stellatus in the upper, middle, and lower spawning zones of the Volga. A correlation between the size of the progeny and environmental factors was revealed. Today, the main factors limiting the efficiency of reproduction in the stellate sturgeon are the numbers of fish admitted to the spawning grounds (especially in 1997 and 1998) and water level in the Volga during the summer low-water season. Measures to support natural reproduction of the stellate sturgeon are proposed.     

Anthropogenic evolution of animals: Facts and their interpretation

Problems concerning microevolutionary transformations in animal populations are considered. It is shown that genetic variation is the main factor providing the basis for adaptation to environmental changes, including toxic pollution. The selection pressure of a toxic factor gives an advantage in survival to more resistant genotypes in animal populations, which eventually leads to the reduction of their genetic diversity and potential for adaptation to other natural or anthropogenic stress factors. Microevolutionary transformations follow the pattern of r-selection, i.e., occur in favor of smaller, earlier maturing individuals capable of expending a greater proportion of their energy resources for reproduction.     

Response of three dominant shrubs to soil water and groundwater along the oasis-desert ecotone in Northwest China

The ecotone from oasis to desert is an important area for combating sandy desertification. Three dominant desert shrubs (Nitraria tangutorum, Calligonuum mongolicum, Haloxylon ammodendrori) were selected in Minqin Oasis, Northwest China, to determine the groundwater level; soil water potential; and change of the three shrubs in density, coverage, and biomass along the natural and seminatural oasis-desert ecotone (ODE), respectively. The results indicated that traits of desert plant interaction with the topsoil water and groundwater depth along the ODE play an important role in generating complex desert vegetation spatial dynamics. Some natural desert plant species with shallow root systems will distribute themselves according to distribution of topsoil water. Thus, the distribution of Nitraria tangutorum had a decreasing trend in distribution along ODE. Calligonuum mongolicum occurs in different trends in natural and seminatural ODE due to utilizing groundwater as well as topsoil water. Some plant species with deep roots, such as Haloxylon ammodendron, will show more degradation near oases and will exhibit an ascending trend along ODE. Therefore, it is of primary importance to protect the integrity of groundwater depth in order to protect the stability of the oasis-desert ecotones. The text was submitted by the authors in English.     

Relationships between pikas (Ochotona, mammalia) and vegetation in Tuva

The burrowing and trophic activities of four pika (Ochotona) species proved to be reflected in the horizontal structure of the biogeocenotic cover. Zoophytochores ofOchotona daurica andO. pallasi pricei burrows correspond to previously described ameboid zoophytochores. Burrows of pikas provide for the growth of pea shrubs (Caragana bungei, C leucophloea), with the formation of specific plant groups under their crowns and on rubble dug out by pikas. In ecosystems of placers, zoophytochores are formed owing to the presence of pika food stores and lavatories, which are the main substrate for vascular plants first appearing among the stones. General ecological (and successional) series characterizing the overgrowing of placers is as follows: (1) separate spots of vegetation with poor floristic composition at the sites of pika food stores (stacklets); (2) groups of spots and simplest complexes; and (3) complex plant communities of pika colonies. Food stores of pikas in Tuva were analyzed.     

The relative importance of sexual reproduction and clonal propagation in rhizomatous herb Iris japonica Thunb. from two habitats of Jinyun Mountain, Southwest China

Reproductive behaviour of clonal plants might change in contrasting habitats. In field and simulated experiments, we studied the relative importance of sexual reproduction and clonal propagation in rhizomatous herb, Iris japonica Thunb. in two forest habitats (BF, bamboo forest and OAFE, open area of forest edge), and effects of population origin (BF vs. OAFE) and environmental effects (shading) on sexual vs. clonal reproduction. In field experiment, the relative importance of reproduction in I. japonica populations was different in two habitats, which showed predominantly sexual reproduction in OAFE and clonal propagation in BF. In simulated experiment, the effect of population origin and light treatment (shading) was significant for reproduction of I. japonica. Clonal propagation was only influenced by population origin, and sexual reproduction was determined both by population origin and light treatment. A trade-off between two reproductive modes exhibited in both experiments. The trade-offs was more obvious in OAFE than in BF because sexual reproduction, resource and inter-specific competition obviously lacked in BF. The results indicated that the selective forces shaping reproduction of I. japonica in contrasting habitats might demonstrate pronounce adaptive population differentiation among forest habitats. Thus, I. japonica populations formed local differentiation by adaptation of reproduction to local heterogeneous forest habitats.     

Trophic specificity of theRana arvalis population from the eastern ural radioactive trace in relation to the state of the soil mesofauna

Studies on the population ofRana arvalis Nilss. frogs performed in the radioactively contaminated area near Lake Berdanish in 1993 revealed a number of features indicating that the contents of nutrients in the organisms of adults and juveniles is low. The analysis of simultaneously collected data on food supply to this population showed that the structure of food chains in the study area is simplified and the diversity and biomass of soil invertebrates (the main food for amphibians) are sharply reduced. These factors account for food deficiency, which manifests itself in a low level of stomach filling and individual energy reserves of the frogs and is reflected in their population characteristics.     

Mating systems in the steppe lemming (<Emphasis Type="Italic">Lagurus lagurus)</Emphasis> and narrow-skulled vole (<Emphasis Type="Italic">Microtus gregalis</Emphasis>) from the Northern Kulunda Steppe

A comparative analysis of reproductive behavior has been performed in the steppe lemming (Lagurus lagurus) and narrow-skulled vole (Microtus gregalis). The results show that the species are similar in certain behavioral features indicative of the stability of mating pairs. However, in the narrow-skulled vole, unlike in the steppe lemming, mature males in olfactory tests show preference for receptive sibling females versus non-kin females. Probably, it is the absence of the incest taboo that allows the involvement of young of the year in reproduction within growing family groups and accounts for “coloniality” of the species.     

Growth and potential reproduction of <Emphasis Type="Italic">Poa crymophila</Emphasis> in response to season precipitation shortage in the Eastern Tibetan Plateau,China

The growing season in 2006 existed a quite less precipitation than previous years in the eastern of Tibetan Plateau, China. In order to explore the response strategies of the grass to drought year, the variations of growth and potential reproduction of Poa crymophila between rich (2005) and poor rainfall year (2006) were studied. Reproductive shoot biomass, above- and below-ground biomass pronounced decreased in the poor rainfall year, but the ratio of above-/below-ground biomass and vegetative shoot biomass increased. Carbon content in inflorescence increased significantly in 2006, but decreased significantly in root. Nitrogen contents and the C/N ratios in plant components were not significantly different. Sexual reproduction in 2005 and 2006 was not different. Season precipitation shortage could result in the higher mortality of vernal budding shoots or tillers. The results suggested that P. crymophila response to poor rainfall year (drought) by a smaller plant body, allocating more proportional biomass to above-ground, altering more carbon to inflorescence, and altering its reproductive way to sexual.     

Chemical composition of water conditioned by crowdedMoina macrocopa (Crustacea: Cladocera)

The chemical composition of water conditioned by colonies ofMoina macrocopa and involved in the regulation of their life cycle was analyzed in comparison with water samples from natural water bodies. Dechlorinated tap water was used as the control medium. The results showed that metabolism of crustaceans leads to an increase in the concentrations of phosphorus and nitrogen in all forms, the appearance of protein and carbohydrate fractions, and changes in the composition of lipid fractions in the water conditioned by their colonies. The contents of all organic components are very low, which makes their identification difficult. Concentrations of substances identified in the conditioned water do not exceed those occurring in nature.     

Modelling of water-ozone reaction system

Mass transfer and reaction kinetics of raw Nile water ozonation are examined. The contact system is a perfectly mixed reactor, and ozone is bubbled through a glass diffuser at different supply rates. The ozone residual is detected for different reaction time intervals. A simple mathematical model is proposed to describe the mechanism of the ozone reactions in the reactor. The proposed model quite accurately describes the mass transfer behaviour in the reactor and determines the ozone dissociation rate constant, together with the effect of the chemical reaction on the ozone transfer. A linear relationship is observed between the ozone feed rate and the ozone residual. First order reaction kinetics describes fairly well the autodecomposition and the global reaction rates of ozone in raw water. The mass transfer coefficient is about 0.18 min⁻¹. The dissociation and the reaction rate constants are evaluated to be 0.33 mg L⁻¹ and 0.19 mg L⁻¹min⁻¹.     

Genetic polymorphism of dwarf Scots pines in the south of Central Siberia

Polymorphism of 11 enzyme systems has been studied in dwarf Scots pine trees occurring on sand dunes and crags in two populations of southern Central Siberia. High genotypic variability of dwarfs and their similarity to normal trees in basic indices of genetic diversity have been revealed. Both populations, including normal and dwarf trees, are in the Hardy-Weinberg equilibrium. The sample of dwarf trees has proved to differ from the “norm” in showing an age-related trend toward decreased heterozygosity. The observed linkage disequilibrium at some pairs of loci can be explained by unequal contributions of trees to population reproduction or by a recent bottleneck event. The populations studied are similar to other Scots pine populations from the Asian part of the species range. Increased frequencies of some rare alleles in the populations from Tuva provide evidence for the probable presence of a glacial refugium for pine in this region.     

Superorganismal Systems in Human Ecology

Comparison of the current approaches to human ecology shows a contradiction between certain views on the subject and the methodology of its analysis. The notion of human ecology as the ecology of the species Homo sapiens is being developed in terms of modern general ecology and should be considered at all organizational levels, from individual to global. Material and spiritual cultures, which are the main adaptations of human beings represent a continuation of the general trend of living matter towards progressive evolution and are accompanied by an increase in orderliness related to the intensification of energy consumption. This superindividual adaptation determines the human capacity for occupying new ecological niches without changing the hereditary background. Therefore, consideration of Homo sapiens at the superorganismal level is of special importance in human ecology. Analysis of this issue shows that the functional patterns of systems belonging to this level have certain characteristics in common with those of the population systems of other species.__________Translated from Ekologiya, No. 3, 2005, pp. 163–170.Original Russian Text Copyright © 2005 by Kryazhimskii, Bolshakov.     

The impact of warming on the appearance of furunculosis in fish of the James Bay region,Quebec, Canada

A regional climate change impact assessment was conducted which investigated the timing of the first appearance of furunculosis caused by the bacterium, Aeromonas salmonicida, in fish of the Ouje-Bougoumou region of northern Quebec, Canada. Historical data were used to assess whether there was a temporal relationship between increased temperatures (observed climate data) and the appearance of furunculosis (traditional environmental knowledge was used to provide context). To project future impacts of climate change, climate models and lake models were used. Regression analysis revealed a significant, positive temporal trend in mean air temperature. The temperature range conducive to A. salmoncida survival coincided with the first appearance of furunculosis. In addition, it is predicted that lake temperatures will remain suitable for the presence of A. salmonicida into the future; it is likely that the disease will persist throughout the twenty-first century. Climate change appears to be a factor explaining the onset of furunculosis; however, other factors/stressors cannot be discounted, such as, the effects past mining activities near the lakes of the Ouje-Bougoumou region have had on the body burden of contaminants in the fish (and the potential effects on the fish immune system).