Nina Vasilieva

Severtsov Institute of Ecology and Evolution · Laboratory of Population Ecology

We investigated acoustic variation responsible for the individuality of alarm calls produced by 50 Brandt’s voles Lasiopodomys brandtii derived from 50 different wild-living colonies. For the first time, we described the calling pattern of Brandt’s voles, producing a long series of short alarm calls with short inter-call intervals. The alarm calls...

Studying intraspecific variation in animal behavior is one of the key trends in recent biology. Comparative behavioral studies of different species require developing an adequate methodology for every new species. We performed three types of behavioral tests with juveniles of the yellow ground squirrel, a large hibernating rodent. Docility tests wi...

Wild cheetahs Acinonyx jubatus of all age classes, from newborns to adults, use their long-distance chirps for communication with conspecifics. We investigated the ontogenetic changes of eight acoustic parameters of the chirps produced by wild-living cheetahs across 14 age classes in Kenya. Chirp maximum fundamental frequency (f0max) was found to b...

Hibernating mammals have annual cycles with strict timing of all processes including reproduction, yet female reproductive physiology is only poorly studied in such species. We investigated the estrous cycle in yellow ground squirrels (Spermophilus fulvus), which hibernate up to 9 months. Using vaginal cytology and serum progesterone and estradiol...

Animal circadian activity was mostly studied in captivity with artificial environment. We performed pioneer study of daily activity using telemetry for yellow ground squirrels (Spermophilus fulvus), burrowing hibernating rodents. Eight individuals were fitted with glued-on radio transmitters contained accelerometers and light sensors in the wild co...

We studied the humoral innate immune responsiveness (HII), i.e. a hemolysis of rabbit erythrocytes by complement proteins, and adaptive humoral (antibody production) immune responsiveness (AHI) to SRBC, morphological and hormonal reproductive characteristics and stress level in male Campbell hamsters kept under long-day (LD; 16D: 8N) and short-day...

The aim of this study was to test the hypothesis that the level of sexual dimorphism modulates the effects of male-female social interaction on the female physiological condition in felids. We predicted that: 1 - contacts of females with males in species with low level of sexual dimorphism in body size will not lead to significant changes in the ac...

The effect of multiple paternity on the development of the humoral immune response in Syrian hamster pups was studied. The paternity type was found to be determined by 10 microsatellite markers. Pups were immunized with T-dependent antigens (fissurella hemocyanin, KLH) at 33 days of age, with the level of specific antibodies (anti-KLH IgG) measured...

Juvenile survival is a key life-history influence on population dynamics and adaptive evolution. We analyzed the effects of individual characteristics, early environment, and maternal investment on juvenile survival in a large solitary hibernating rodent – yellow ground squirrel Spermophilus fulvus using Cox mixed-effects models. Only 48% of weaned...

For human-audible vocalizations (below 20 kHz) of rodents, subterranean lifestyle results in low-frequency calls coupled with low-frequency hearing. For ultrasonic vocalizations (above 20 kHz), the effect of subterranean lifestyle on the acoustics is unknown. This study fills this gap of knowledge, by comparing vocalizations of two closely related...

Acoustic individuality is present in diverse taxa of mammals and birds, becoming especially prominent in those age groups for which discriminating conspecifics by voice is critically important. This study compares, for the first time, the ontogenetic changes of acoustic individuality of ultrasonic and audible calls (USVs and AUDs) across 12 age-cla...

Inbreeding depression is commonly considered an evolutionary influence on pre-copulatory mechanisms of inbreeding avoidance. Inbreeding may be minimized by: (1) delayed maturation and reproduction, (2) sex-biased dispersal, (3) behavioural avoidance of mating with relatives, and/or (4) mating by females with multiple males (polyandry). Time constra...

The development of industry and agriculture and the continuous growth of human population on Earth have dramatically increased anthropogenic pressure on natural ecosystems and wildlife. As a result, fragmentation of the natural habitats and the decrease in genetic diversity in these populations increase the probability of reproduction with genetica...

Fitness consequences of early-life conditions remain unclear and poorly studied in mammals. Based on long-term observations of yellow ground squirrels (Spermophilus fulvus), we identified early determinants of female fitness by analyzing the effects of early-life individual and environmental characteristics (weaning weight, weight gain rate, date o...

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)....

In a study of gerbils with contrasting social and mating systems (group-living monogamous Mongolian gerbil Meriones unguiculatus, solitary non-territorial promiscuous midday jird M. meridianus, and solitary territorial promiscuous pale gerbil Gerbillus perpallidus), we employed partner preference tests (PPTs) to assess among-species variation in so...

Objectives: Studying animal vocal aging has potential implication in the field of animal welfare and for modeling human voice aging. The objective was to examine, using a repeated measures approach, the between-year changes of weight, social discomfort score (bites of other hinds on hind pelt), body condition score (fat reserves) and acoustic varia...

In female terrestrial mammals, vocal aging has only been studied in humans and pandas. In cervids displaying convergent sex dimorphism of vocal apparatus with humans, vocal aging is only investigated in males. This cross-sectional study examined acoustic variables of nasal (closed-mouth) and oral (open-mouth) contact calls of 32 farmed Iberian red...

Blood analysis has recently become a popular tool to assess the welfare of the wild cats. However, the estimates of blood parameters may depend on the sampling method. We have tested (1) if the sampling procedure influences blood parameters and (2) what parameters are the most efficient in assessing the physiological status in wild cat species. We...

The problem of the optimal distribution of time and energy between reproduction and the other vital functions and the choice of optimal reproductive tactics concerns all animals. The sequence of decisions largely determines overall individual reproductive success and fitness. The goal of the study was to summarize the factors determining the reprod...

Androgen-dependent male sexual traits (STs) as well as immunocompetence are theoretically assumed to be key indicators of a male’s quality for the mate-choosing female. We studied mate choice by sexually motivated (SM) females of Campbell’s dwarf hamsters. Females chose between 2 tethered male siblings that differed in expression of STs. Males were...

Проблема оптимального распределения времени и энергии между размножением и другими жизненными функциями, выбора репродуктивной тактики в условиях репродуктивных компромиссов касается всех животных. Совокупность и последовательность решений во многом определяют по- жизненный репродуктивный успех и приспособленность. Цель работы – обобщить исследован...

Sexual conflict theory suggests that female breeding success is strongly influenced by individual life history and environmental conditions and is much less affected by mate availability. Female mating failure due to a shortage of males remains poorly studied and understood. We present data on the effects of male availability on female breeding suc...

Life-history theory predicts that in hibernators age of maturation is related positively to body size and negatively to the duration of active season aboveground. Yellow souslik is a large-sized ground squirrel with long hibernation, which suggests late maturation. We used four-year field observations of marked individuals to determine the age of m...

Based on 4-year field observations of yellow ground squirrels (Spermophilus fulvus (Lichtenstein, 1823)), we determined whether female reproductive effort, annual reproductive success, and survival were dependent on age, body condition, time of emergence from hibernation, and previous reproduction. The probability of weaning a litter did not vary w...

The questions of individuality and stability of cues to identity in vocal signals are of considerable importance from theoretical and conservation perspectives. While individuality in alarm calls has been reported for many sciurids, it is not well-documented that the vocal identity encoded in the alarm calls is stable between different encounters w...

Although individuality in alarm calls has been reported for many ground-dwelling sciurids, the degree to which the vocal identity encoded in alarm calls is stable with time has been studied only for a single sciurid species. Thus, no comparable data are available. We examined the retention of the vocal keys to individual identity after hibernation...

The long-teeth ground squirrel (Spermophilus fulvus), as compared to other ground squirrels, has a large body size (up to 2 kg) and extremely short active season (not more than 3 month). The growth rate of S. fulvus was studied in the wild, in Saratov region (Russia) in 2005–2007. The animals were permanently marked in the colony in 2001–2007, and...

The relationships between the body mass, date of emergence and frequency of social contacts in juveniles of long-teeth ground squirrel were studied. The body mass and date of emergence varied strongly among litters, and both factors affected the social activity of pups: the earlier juveniles emerged and the greater was their body mass at emergence,...