Lyapkov S.M., Ibragimova D.V.
Variations in demographic and morphological characteristics of mature Rana arvalis individuals from a transformed and a natural habitat near Surgut were studied. The females from the transformed habitat were reliably smaller than males and significantly younger and smaller than females from the natural habitat. The direction of sexual differences in both populations was the same as in most of the populations of the species studied earlier. The low values of the population means of body length (but not of age) revealed in the populations living near the northern range limit correspond to the general trend in body size variation of adult frogs in relation to the length of the activity season throughout its vast range. Sexual differences in most of the traits studied were only due to variations in body size; those in few traits were not dependent on body size, while such traits were most likely to determine the male mating success. No morphological specificity related to different environment conditions in both neighboring populations was revealed. The relative femur and shin lengths were significantly larger in males than in females, not only in the two Surgut populations, but in all populations studied earlier; these differences were not related to the greater body length in males. In both sexes, trends in an increased relative head width and a decreased relative femur and shin lengths were found when shifting from the southern to the northern population; this trend was related to neither the mean age nor body length.
The content of exo- and endogenous water in the body of a honey bee was studied in relation to age, season and the physiological state of the bee colony. The water content in the carbohydrate food consumed by the bees was shown to affect brood reproduction by the colony. The behavior of the bees supplying the colony with water was investigated and the amount of water used for larval food dilution and nest cooling estimated. Seasonally broken and resumed reproductive functions of the queen were shown to depend on the dynamics of the water contained in the digestive tract of worker bees.
Foraging techniques influence morphological peculiarities and ecological specializations of species, also determining their organization in a community. The foraging behavior of forest ground insectivorous birds remains the least explored due to the difficulty of observing them in the wild. We studied the foraging behavior of 4 nightingale species in an outdoor aviary where they were given a choice of typical foraging substrates. Two categories of caged young birds, hand-raised and wild, were tested in relation to 5 aspects of behavior: foraging intensity, background activity, attack maneuvers, attack direction, and substrate preference. We used the original set of coefficients for converting the bird activity into energy expenditure units in terms of the basal metabolic rate. We measured behavioral variables (except the total intensity) as the fraction of total energy expenditure for the given aspect to reduce by-product variation. Three principal components explained the interspecific differences in individual behavior means more than for ¾. The first one corresponds to the foraging intensity and ranks the species according to the decreasing body mass. The second component distinguishes the Siberian Rubythroat (L. calliope) tactics of complex investigation of dense vegetation thickets from the Rufous-tailed Robin (L. sibilans) manner of the extensive ground surface exploration. The third principal component contrasts the Bluethroat (L. svecica) tactics - alternation of moving, waiting and long sally-hovers - with the very intensive short aerial maneuvers of the Siberian Blue Robin (L. cyane). The species-specific foraging traits appear in young birds independently of the own wildlife experience. While learning by doing, they increase the foraging intensity, as well as strengthen specific traits. Differential substrate choice seems to be the leading feature defining the foraging tactics in the nightingales, while the other aspects are the following and partly dependent on the properties of the encountered food items.
The structure of the upper and lower fourth premolars of the brown (Ursus arctos) and polar (U. maritimus) bears has been studied. Teeth morphotypes have been identified and described. Morphotype frequency is given both for individual samples and the species as a whole. The brown bear is revealed to show a greater degree of morphotypic variability of the premolars. The brown bear is characterized by a more complex structure of the corona compared to the polar bear. It also shows vaster geographic variation of the tooth index complexity. The brown bear populations from Hokkaido have the most complex p4 and demonstrate considerable morphotypic variability. Evolutionary changes of the last premolars in the Ursus subspecies are represented in grinding surface simplification, which is most strongly pronounced in U. maritimus. The teeth of the polar bear are generally better adapted to carnivory than the premolars of the brown bear. Due to fast adaptation to hypercarnivory, the U.maritimus premolars obtained a unique appearance and specific features. Both teeth provide enough information for a rather precise species identification of the two species under study.
New data are presented on the distribution of Histeridae and Scarabaeidae in Russia and Kazakhstan. Three species, Pholioxenus schatzmayri J. Müller 1910, Mendidaphodius linearis (Reiche et Saulcy 1856) and Onthophagus ponticus Harold 1883, are recorded from Kazakhstan for the first time, and one more, Atholus scutellaris (Erichson 1834), is new to the fauna of Russia. Distributions are refined for Microsaprinus therondianus (Dahlgren 1973), Hypocacculus biskrensis (Marseul 1876), Paravolvulus refector (Reitter 1904), Hister megalonyx Reichardt 1922, Bodilus longipennis (Rakovič 1984), Protaetia cyanescens jacobsoni (Kiseritzky 1910), Valgus hemipterus (Linnaeus 1758). Zoogeographically, all these species are associated with four regions: Hesperian, European, Sahara-Gobi (Seti) or Scythian.
Two new species of oribatid mites of the superfamily Oripodoidea (Acari, Oribatida) are described from Trinidad and Tobago. Scheloribates (Scheloribates) tobagoensis sp. n. (Scheloribatidae) differs from S. (Scheloribates) papillaris Tseng 1984 by the structure of rostral and lamellar setae and leg solenidia, the length of the prolamellae, the absence of aggenital setae and the reduction of setae on tarsi III. Areozetes ryabinini sp. n. (Haplozetidae) differs from A. altimontanus Hammer 1961 by the structure of bothridial and notogastral setae and the rostrum, and the number of claws on the tarsi.
Shchipanov N.A., Mahanko E.V.
Larvae and nymphs of the ixodid ticks (with distinguishing neither developmental stages nor tick species) feeding on 6 rodent and 4 insectivore (Lipotyphla) species were taken in the course of an introvital capture-mark-recapture study of small mammals conducted in 2014-2016 in a rural landscape of the Tver Region. Five habitats were surveyed: a conventional primary spruce-pine forest, a humid grassland, a glade (19 years old) patch in a spruce-pine forest, an abandoned potato field overgrown by a young mixed forest (19 years old), and an abandoned former village area. Random sampling revealed the presence of adult Dermacentor reticulatus, Ixodes ricinus and I. persulcatus in the area. The number of ticks on the small mammals consistently decreased in the series: raw grassland, wasteland, glade, growing forest. Both the extensiveness and intensiveness of tick infestation of small mammals were the highest in the common shrew (S. araneus) which supported about 88% of all ticks found on small mammals. Only this species showed the population abundance being related to the infestation rate of small mammals by ticks.
Mekhanikova I.V., Vorobyeva S.S.
The authors analyzed the diet of a symbiont, Brandtia parasitica parasitica (Dybowsky 1874), of Baikal sponges recorded during an ecological crisis in the littoral area of Lake Baikal. In June 2015, the main components of the diet of the amphipod that lived on ill sponges were fine detritus, sedimented crysophytes of the genus Dinobrion, and planktonic diatoms of the genus Synedra. These latter algae dominated phytoplankton in the southern part of Lake Baikal during the study period. Abundant blue-green algae were observed on the surface of ill sponges, but B. p. parasitica did not feed on those algae. As the toxins secreted by blue-green algae are known to render negative impacts on hydrobionts, the sponges massively overgrown by blue-green algae were to result in a reduced population of the symbiotic amphipod.
Research on the project “Traditional knowledge of Chukotka’s native peoples regarding polar bear habitat use” was conducted in 1999-2003. One of the main objectives of the project was to collect information about the whereabouts of polar bear dens. Studies were based on individual interviews with the most active hunters and elders from the native villages located within the polar bear range. 53 people from 20 villages were inquired. Data on 278 den locations in the period from 1943 to 2002, as well as on the patterns of denning area use were obtained. All dens and denning areas were mapped. Based on this information, 17 areas with regular and relatively high den densities were outlined. The total number of females breeding annually in the 1990’s on the Chukotka mainland and offshore islands was approximately estimated as amounting to about 100-200 individuals. Possible options for changes in female reproductive strategy of the Alaska-Chukotka subpopulation in relation to an increasing rate of sea ice habitat loss in the Pacific part of the Arctic are considered.
Kondratyuk E. Yu., Zadubrovskiy P.A., Lopatina N.V., Litvinov Yu. N.
The dynamics of glucocorticoid concentrations was analyzed for the first time in immature males of the Tuva vole, a poorly-known species of mountain rodents, both at rest and during a pharmacological stimulation of the hypothalamic-pituitary-adrenal axis (HPA axis). Corticosterone was shown to be the dominant glucocorticoid hormone, the level of which is almost five times higher than the basal concentration of cortisol, a secondary glucocorticoid. The concentration of the dominant hormone increased 12.7 times, that of the secondary hormone 2.1 times following an hour long stimulation of the HPA system. The basal levels of the dominant and secondary glucocorticoids returned to the norm after 6 and 24 hours, respectively.
New records of sables captured in the Sverdlovsk Region in 2014-2016 are presented at a distance of 133 to 203 km away from the southwestern range limit of this species, invading pine marten habitats. A brief description, pictures, mapped locations and morphometric data of the animals are given. A sable female ear-tagged in the Pechora-Ilych State Nature Reserve traversing a distance of 233 km towards the vicinity of the town of Karpinsk before being captured is reported. Violations of range limits are made possible because of the local quantitative prevalence of one species over the other.
Trepet S.A., Eskina T.G.
The ratio between ungulate biomass as potential victims and the wolf as the main predator was studied in different parts of the Caucasian Nature Reserve: northern, eastern and southern. An optimal ratio of ungulates to wolves is shown to have been biased during a stable period in the 1980’s for a number of peripheral areas of the nature reserve totaling about 50 thousand hectares in area. Following a crisis of the 1990’s, these areas were joined not only by all peripheral, but also some of the central parts of the nature reserve. From the point of view of an equilibrium in the “wolf-ungulates” system, at present the functioning of the ecosystem is close to natural at best only over one-third of the territory. One of the main reasons for this lies in man’s intensified economic activities of various kinds just at the borders of the nature reserve and their inevitable impacts rendered on the protected ecosystems.
Five of the seven modern species of the family Anomaluridae were studied. Significant intergeneric differences in the structure of the tongue between Anomalurus and Idiurus were identified, which affect even such taxonomically important features as the number of circumvallate papillae (three in Anomalurus, two in Idiurus), and the distribution pattern of fungiform papillae. Within the genera a parallel interspecific variability was observed, which manifests itself in a decrease in the total number of fungiform papillae. The tongue structure in Anomalurus is shown to correspond to the generalized version initial for the order, whereas in Idiurus, it has clear signs of morpho-functional specializations.