Contents: Volume 18 (2) 2019 (Printed 24 December 2019)

Ambaryan A.V., Voznessenskaya V.V., Kotenkova E.V.

P. 67–79

Closely related species with different mating system may be the most suitable model taxa for studies aimed to highlight the cause formation of species-specific peculiarities of sexual behavior and behavioral mechanisms of precopulatory isolation. The current study aimed to clarify the role of the mating system and lifestyle, including ecology features, in patterning of behavioral activities during mating, as well as the role of behavioral patterns in the precopulatory isolation of closely related Mus taxa. Test subjects were closely related sympatric species: polygynous/promiscuous M. musculus and presumably monogamous M. spicilegus, reproductively isolated in nature. Dyadic encounters of male and receptive female were conducted in clear chambers and the behavior was recorded by means of video camera. Sexual behavior, culminating in ejaculation, was observed in conspecific dyadic encounters only; it occurred more frequently and with longer duration in males of M. spicilegus, than in males of M. musculus. In conspecific encounters, males of M. spicilegus exhibited a higher level of affiliative behavior than females. In both species total frequency and duration of aggressive behavior was higher in females compared to males. In heterospecific dyadic encounters the behavioral pattern of males and females was strictly different from those in conspecific encounters, and the elements of aggressive behavior prevailed. We demonstrated that not only the pattern of sexual behavior is important for reproductive isolation, but also all types of behavioral interactions preceded copulation. In Mus species different stereotypes of mating behavior during the encounter of potential sexual partners can prevent successful copulation and may be associated with mating system.

Antonevich A.L., Alekseeva G.S., Vasilieva N.A., Pavlova E.V., Loshchagina J.A., Duplyakina S.Yu., Naidenko S.V.

P. 80-90

Social play in young mammals reflects behavioral development, play can be affected by differences in development timing and species biology. We compared social play frequency changes in three felids: Eurasian lynx (Lynx lynx), Amur subspecies of leopard cat (Far-Eastern wildcat) (Prionailurus bengalensis euptilurus) and domestic cat (Felis catus). Social play is often expected to increase social tolerance and cohesion in a litter. Socially living domestic cat had contact and non-contact social play rates at the same level as solitary lynx and leopard cat. Whereas lynx differed from the other felids in lower social play rates at the age from one to one and a half month. Two types of social play were changing differently. Non-contact play rates, attributed to predatory skills development, were synchronized among species by age of kittens. Whereas contact play changes, attributed to communication development, were sensitive to the developmental stage. Contact play intensified in lynx much later than in the other felids probably due to a later onset of weaning. The period of extraordinary low contact play rates coincided with the onset of spontaneous sibling aggression, unique for lynx. After a period of spontaneous sibling aggression contact play rates in lynx increased to the level that other felids had. Observed social play changes and differences reflect development timing and species-specific features in felids.

Burova V.V., Nikulina E.D.

P. 91-98

Preliminary data on faunal remains from the Holocene site Ruchei Akimov located in the Northern Angara region are presented. Cultural remains were found in three horizons. The goal of this study is to present new data on the archaeozoological collection excavated in 2011–2012. Altogether we recognized 11 taxa: Homo sapiens, Castor fiber, Canis familiaris, Ursus arctos, Martes zibellina, Equus sp., Cervidae gen. indet., Cervus elaphus, Capreolus pygargus, Alces sp., and Rangifer tarandus. This contribution focuses on archaeozoological treatment of the bones, including the measurements for bones identified to species, and description of bones modified by humans. The predominance of red deer and the presence of horse in the Neolithic – early Bronze Age are distinctive features of the site Ruchei Akimov. Bone remains with traces of human activity indicate hunting and fishery practiced in all periods of site use.

Volpert Y.L., Shadrina E.G.

P. 99-106

Distribution of small mammals has been analyzed on the territory of the Western Yakutia in the corridor between 112° and 116° E and between the Lena River valley (starting from the Vitim River mouth) and the Anabar and Olenyok interriverine area (59–71° N). The material was collected in 2002–2017 in 11 sites within the taiga zone (from the border between the middle and south taiga to the northern border of the north taiga subzone). A total of 11200 cone-days and 12500 trap-days were accumulated and 4200 specimens of small mammals belonging to 21 species were collected. The highest species richness of small mammals is registered on the border of the south and middle taiga (17–18 species). In the north taiga the fauna of small mammals is represented by 8–9 species. This decrease from south to north is uneven: in the river valleys the species richness is generally higher than in the watersheds. The penetration of taiga species to the north is of a larger scale than that of tundra species into taiga habitats; therefore, changes in beta-diversity occur mainly due to the distribution limits of boreal species. Besides, in the absence of geographic barriers, a sharp decline in species richness is observed between 65° and 66° N, which coincides with the boundary between the middle-taiga and north-taiga subzones. Out of the climatic factors, the distribution of small mammals is affected mainly by winter precipitation, winter duration, average July temperature and average annual temperature, while dependence on such factors as January temperature and summer precipitation was not found.

Kruskop S.V.

P. 107-109

While working with the Prof. Abe’s collection, which is stored at the Hokkaido University (Sapporo), a specimen of the fruit bat Eonycteris spelaea (No. 56289) was discovered, possessing additional molars in all four tooth rows. Such type of polyodontia is not known for this species, and is extremely rare for Pteropodids as a whole. Also, we did not found any mention of cases where additional molars would develop simultaneously on the lower and upper jaws. Among the examined 25 specimens of Eonycteris spelaea, two cases of olygodontia (plus one, probably representing an artefact of metabolic disorders) and five cases of polyodontia were identified. For comparison, in a sample of 40 individuals of three different species of the genus Rousettus, not a single case of polyodontia was found.

Lissovsky A.A., Kadetova A.A.

P. 110-114

Variation in the morphology of the occlusal surface of the third lower premolar tooth was examined in 69 skulls from adult specimens of four pika species. Variation was examined using standard geometric morphometric techniques as well as analysis of distances between landmarks (with and without accounting for the size factor). The results were checked on a sample of 46 specimens, specifically by comparing inter-species variance in dental and cranial features. Interspecies variation was low in the case of shape-only analysis of features of the third lower premolar, independent of the method used. Adding the size factor to the analysis notably increased the interspecies variation in teeth. Analysis of cranial data displayed more prominent interspecies variation compared to dental data, both with and without information on skull size. Sexual variation was minimal in all analyses. Thus, we suggest using information on tooth size for the purpose of species identification on the basis of the morphology of the occlusal surface of permanent teeth in pikas. In this case, morphological study of the occlusal surface of teeth could contribute to Ochotona species identification.

Stakheev V.V., Obolenskaya E.V., Fomina E.S., Panasyuk N.V.

P. 115-119

The distribution and genetic polymorphism of the bank vole in the south of its distribution range in European Russia are discussed. Myodes glareolus from this territory displays lower values of haplotype diversity than voles from the central parts of the distribution range; while nucleotide diversity is comparable in both territories. The results suggest the long-term existence of fragmented populations of the bank vole in southern European Russia, as well as negative periods in the history of populations.

Tu L.N., Hai B.T., Motokawa M., Oshida T., Endo H., Abramov A.V., Kruskop S.V., Minh N.V., Duong V.T., Minh L.D., Tham N.T., Rawson B., Son N.T.

P. 120-136

Field surveys in the Song Thanh and Saola Quang Nam Nature Reserves (Quang Nam Province, central Vietnam) were conducted in 2018 and 2019. In total, 197 individuals of small mammals were captured and studied in the field or collected as voucher specimens. Based on these data, an updated checklist of small mammals of Quang Nam Province is provided. A total of 78 species in 15 families and 6 orders is recorded from both reserves: viz., 57 species in the Song Thanh Nature Reserve and 39 species in the Saola Quang Nam Nature Reserve. Records of 20 species are new to the mammal checklist of Quang Nam Province.

Englund J.K.Å.

P. 137-145

The size of animals is often related to food abundance in the year an individual is born and thus the mean size of the animals often varies between birth cohorts. Neglecting these complications may result in false conclusions in analysis of morphological variation. In this study I examine how the lengths of the skulls and the long bones of red foxes Vulpes vulpes varied between birth cohorts and in relation to fluctuations in their main food (voles). Foxes, born in the northern half of Sweden when the voles are extremely common, have larger skulls and longer legs than foxes born when the voles are scarce. The relation between the abundance of voles and the size of the skulls and the long bones is less pronounced southwards and ceases in central Sweden. Neglecting these complications may result in false conclusions. When the voles are scarce the reduction of the size of the skull is larger counted as a percentage, than the shortening of the long bones. This indicates that in northern areas with much snow and long winters it is more important for the foxes to retain the length of the legs than to keep the length of the skulls.