Vol 44, No 7 (2017)

Long-termed intersexual friendly relationships between males and females of the Brauner’s lizard are characterized by high levels of spatial association and high frequency of affiliative behavior between partners (see report 1). In present article we consider changes in the frequency of affiliative behavior in males (Am) and females (Af) after the first appearance of female on the male’s territory and conditions for the transition of lizard to stable residency (SR). Generally, Am becomes stable during the first days of initial period and does not change later. This fact suggests that in most instances male’s choice criteria are some peculiarities of the female’s exterior. In the initial period, Af is always low, however, gradually rises to the level of Am if Am is high. The main condition of female’s SR is high Am of the owner of the territory where female establishes her comfort areas. Hence, social partner choice in female is based on male’s behavior, and high Am triggers the formation of friendly interrelations. Significant correlation between social and sexual interrelations is absent. As can be judged by female’s reactions to male’s sexual behavior, his sexual activity is rather a factor of social disintegration. Structure of costs for social partner search is different in males and females, and these differences well harmonize with differences in gender strategies of partner choice. The social strategies are well interpreted in terms of the optimal foraging theory.

Variability of the shell size characteristics was studied in the terrestrial mollusk Chondrula tridens (Müller, 1774) from highland and plain habitats in the forest–steppe of the Volga River basin. The shell height (SH) and width (SW), the height and width of the mouth, and the SH/SW ratio mostly contribute to the species variability. The SH/SW ratio reflects the species–specific constitution of the shell. Analysis of the elementary features and proportions, as well as of the mouth armament of shell structures, indicates significant heterogeneity of the species. The presence of scarps and rock outcrops in some regions studied explain large sizes of snail shells. The decrease in SH, increase in the roundness of shells, and better development of the mouth teeth in mollusks inhabiting the chalk steppe of the southern forest–steppe reflect their adaptation to more xerothermic conditions.

Comparative analysis of the ontogeny of representatives of two sister taxa (Cladocera and Cyclestherida) showed that the paedomorphic morphology of cladocerans (the small number of thoracic segments and segments of branches of antennae II, and the reduction of the carapace) was caused by the cessation of development of the somatic structures at early larval stages of ontogeny. It is demonstrated that this stop is not associated with the accelerated development of the reproductive system (progenesis), since it takes place long prior to the beginning of reproduction. In accordance with this fact, the past hypotheses that cladocerans evolved from the reproducing larvae of the ancestral form or that they are early maturing metanauplii should be recognized as erroneous. Cyclestheria. The origin of Cladocera from a Cyclestheria-like ancestor should be regarded as neotenic, taking into consideration the extended interpretation of this term.

This article discusses the species wealth and ecological and faunogenetic structure of nesting avifauna at three different sites on the Black Sea coast in Abkhazia in the vicinity of the Pitsunda–Mussera Reserve (the Pitsunda Lowland, the Mussera Hills, and the Gudauta Plain) versus the avifauna of the Colchis Lowland in Georgia and the Imereti Lowland in the lower reaches of the Mzymta River in Russia. This comparison has revealed the key biotic, abiotic, and anthropogenic factors that determine the formation of regional faunas. The comparative analysis of the avifauna of the Abkhazian coast in four time spans (the beginning of the 20th century, the middle of the 20th century, the 1960s–1980s, and the beginning of the 21st century) has determined the basic trends of its transformation, the rate of changes being observed, and the sources of the formation of the fauna of separate bird species and the causes of their disappearance. The data obtained were used for predicting the development of the avifauna of Colchis landscapes in Abkhazia for the next 100 years.

The breeding biology of the parakeet auklet was studied in 1989–2012 on Talan Island, which is located in Tauiskaya Bay in the Sea of Okhotsk. In 2008, its population amounted to 3000–4000 individuals, and 70% of the birds nested on the western slope. In 2008, the average density of nesting on this part of the island was 0.018 pairs/m². Most of nests were noted along the slope base (5–20 m a.s.l.), while the largest density in these sites was 0.035 pairs/m². The time of egg laying varied from June 4 to June 14, and the longterm average annual date fell on June 8. The latest date of egg laying (June 12–14) was observed in 1995, 1999, and 2001, which was due to the time of ice crushing nearby the island. Hatching in different years started on July 9–19 and ended in late July–early August. The weight of hatchlings was 20–33 g (on average, 27.9 g). In different years, the maximum weight of 22-to 29-day-old nestlings was 173–263 g. By the time of fledging, their weight had decreased to 168–252 g, while the daily increase in weight for the periods of chicks staying in the nests was 4.06–6.47 g in different years. Young birds left the island in the period from the middle of August to the first ten-day period of September; the average age of fledglings was 31–35 days in different years. The reproductive success of the parakeet auklet varied from 0 to 83.3% (on average, 44.3%) and was mainly determined by the survival of chicks at different stages of their development. The main limiting factor of the reproductive success is the reduction of forage availability and abundance, which is largely due to unfavorable weather conditions (long cyclones with storm winds), as well as various hydrobiological changes in the environment. The influence of anxiety and predation was not significant with respect to adult birds, but these factors can cause death of clutches and chicks, and, being combined with unfavorable weather conditions, their effect increases.

The Late Pleistocene and Holocene Galliformes faunas from the Crimean Mountains included seven species of birds belonging to the families Phasianidae and Tetraonidae: Phasianus colchicus, Alectoris chukar, Perdix perdix, Coturnix coturnix, Lyrurus tetrix, Lagopus mutus, and Lagopus lagopus. The habitation of Gallus representatives in the Crimea in the Late Pleistocene has not been confirmed. Representatives of the family Phasianidae were present in the Crimean fauna at least for most of the Late Pleistocene. All of them survived until the Late Holocene. Pheasants became extinct around the eighteenth century, and the rock partridge seems to have disappeared only in the first half of the twentieth century. The species were restored in the Crimea in the second half of the twentieth century. Gray partridges were common resident birds of the Crimean Mountains throughout the Late Pleistocene and Holocene. Quail was not a numerous breeding species of the Crimean Mountains at the same time, but mass migration of this species through the Crimea appeared only at the end of the Late Pleistocene and evolved over the Holocene warming. Species of Tetraonidae appeared in the fauna of the Crimea long before the beginning of the cold-phase maximum of the last glaciations but no later than 28000 years ago and became extinct in the Early Holocene warming but no later than 9000 years ago.

House and tree sparrows were common in cities and towns of the Lower Ob River basin down to the mouth in the 1970s–1980s. Currently, the house sparrow has spread in the localities of the middle and northern Yamal areas, whereas the tree sparrow has almost disappeared from the Lower Ob River basin. The house sparrow has moved to the Subarctic owing to the presence of localities with residential houses and warm shelters for vehicles and equipment, as well as houses near the oil and gas drill sites. This species reproduces during the same periods as in the temperate latitudes, annually brings two clutches, has an extended molting period, and migrates only in spring. The tree sparrow has similar ecological characteristics but prefers old wooden buildings. The southward shift of the distribution range of the tree sparrow is most likely associated with a decrease in the population.

The features, population characteristics of reproduction, nutrition, and lifestyle of an extremely poorly studied narrow-range species of underground rodents—the false zokor (Myospalax aspalax)—have been described on the basis of original field materials. The data were obtained within the Russian part of the species range in Zabaikal’skii krai. The false zokor is characterized by a pronounced sexual dimorphism in body size (males are larger) and a predominance of females in the population. Mating takes place in April; at other times of the year, zokors lead a solitary lifestyle. The size of the brood is small: 3.7 embryos per breeding female. Their preferred food is bulbs and rhizomes of Allium, Thermopsis, Phragmites, and Leymus. In Eastern Transbaikalia, they are active in winter.

We examined functional teeth (except for upper canine teeth) of Pacific walruses that died or were harvested on the coast of the Chukchi Peninsula in 2005, 2007–2008, and 2010–2011. The dynamics of deposition of annual cement layers was investigated. The rate of cement deposition on the walls of tooth roots decreased significantly with age. The rate of its deposition on the lingual side of the upper teeth was much higher than that on their buccal side, but no such differences were observed on the lower teeth. The same cement layer was deposited unevenly in different parts of teeth (on its different sides and levels) with a general tendency of increasing in the width of the layer from the top to the lower parts of teeth. As a result of local widening of some cement layers with age, the tooth surface became rough, and knolls and rollers appeared there. As the age increased, external changes in teeth occurred: they became larger, more rounded, and heavier. We described a method for the preliminary determination of the relative age of walruses based on the ratio between the width of cement and dentin on the attrition surface of lower teeth (without cutting).