Russian Journal of Zoology

The petrophilic Euro-Nearctic genus Petrobius Leach, 1809 includes eight described species found in open rocky habitats in North America, Europe, the Mediterranean, and the Black Sea region. Petrobius bakhchisaraiensis sp. n. is most similar to the species of this genus from the Caucasus and Crimea: P. caucasicus Kaplin, 2010; P. crimaeus Kaplin, 1983; and P. montanus Kaplin, 2021. All these species differ from one another in the coloration and structure of the eyes and ocelli, the maxillary palps, the coxites of abdominal segment IX, and the male genitalia.

New data are presented for a species group close to Thinodromus (Amisammus) arcuatus (Stephens, 1834), distinguished by the structure of the male genitalia and hereafter referred to as the “arcuatus” species group. Until now (Gildenkov, 2000, 2001, 2019), in addition to T. arcuatus, this group included further 5 species from the Palaearctic: Thinodromus (Amisammus) motschulskyi (Hochhuth, 1860), Thinodromus (Amisammus) dilaticollis (Eppelsheim, 1884), Thinodromus (Amisammus) pilosellus (Eppelsheim, 1890), Thinodromus (Amisammus) japonicus (Cameron, 1930) and Thinodromus (Amisammus) renominatus Herman, 1970, as well as 3 species from the Oriental Biogeographic Region: Thinodromus (Amisammus) diancangensis Gildenkov, 2019 from Yunnan, China, Thinodromus (Amisammus) gentlus Gildenkov, 2019 from northern India and Nepal, and Thinodromus (Amisammus) smetanai Gildenkov, 2019 from Taiwan, China. As a result of studying the type and other vast material of T. arcuatus, T. renominatus and T. motschulskyi, a new synonym is established: T. (Amisammus) motschulskyi (Hochhuth, 1860) = Thinodromus (A.) renominatus Herman, 1970, syn. n. In addition, new records of T. arcuatus and T. motschulskyi are given.

The structure and population size of the Great Crested Grebe (Podiceps cristatus) in Moscow have been studied since 1998, with wintering birds being counted since 1985. Surveys were conducted on 150 ponds and 23 rivers of Moscow, and the number of chicks in each brood was noted. The date of hatching was determined by the countdown method based on the age of the chicks. Great Crested Grebes have been nesting in Moscow since the late 1990s, their number increased to 86 pairs by 2025 and continues to grow significantly (r_s = 0.87, p < 0.05, n = 15). The number of wintering birds correlates with the number of birds nesting in the previous season (r_s = 0.71, p < 0.05, n = 28). The number of broods is related to neither the length of the frost period nor the average daily, nor the minimum air temperatures in March, April and May. The similarity of the Great Crested Grebe breeding cycle to other waterfowl species depends on the time it starts from the time of transition of the average daily air temperature through 0°C. The earlier the positive air temperature was established, the more time has passed from that day to the beginning of egg-laying in females (r_s = 0.86, p < 0.05, n = 28). This, however, does not lead to an increase in the number of nesting birds. No effects of over-crowding have appeared in the Great Crested Grebe population. Brood size reduction with an increase in the number of females is likewise typical of other waterfowl, primarily mallards. The colonization of the Moscow metropolis was preceded by an increase in the number and expansion of the European distribution range in the 20th century, as well as the formation of a network of artificial reservoirs and specially protected natural areas. The spatial distribution of nesting Great Crested Grebes until 2004 was determined by the location of colonies of Black-headed Gulls (Chroicocephalus ridibundus), but now their relationship has weakened. The population of the Great Crested Grebes in Moscow obviously starts from the suburbs and develops as the region urbanizes as in many other birds. A decrease in the escape distance, neophilia, and nesting in open reservoirs and on artificial substrates indicate a deepening of the development of urban habitats.

In physiology and behavioral disciplines stress is traditionally understood as a neuroendocrine mechanism of body adaptation to the damaging effects of stress factors (stressors). However, in evolutionary biology, stress and a stressful environment (stressor) are equated; stress being considered as the cause of evolutionary innovations based on mutations or epigenetic modifications that affect the individual developmental trajectory. Epigenetic variations are reversible, but can be inherited across generations and genetically fixed by natural selection. Modern research convincingly confirms the significant and possibly even the primary roles of inherited epigenetic variations in the evolution of adaptive traits. Meanwhile, the role of physiological stress in evolution is twofold. The effects of chronic stressors may be the root cause of adaptive innovations. At the same time, physiological stress on the microevolutionary time scale seems to be a primarily conservative phenomenon. This conclusion follows from the analysis of the role of physiological stress in the regulation of population cycles of small mammals in experimental and descriptive studies performed by population ecologists in the second half of the 20th century and at the beginning of the current century, being supported by modern research involving molecular genetic methods. These modern studies re-actualize the formerly popular concept of population self-regulation. As an evolutionary factor, physiological stress at the population level acts not so much as the cause of the appearance of novel traits and properties, i.e. adaptive evolution traditionally associated with motion, but as a mechanism aimed at preserving the adaptive norm (stable genome). While remaining a source of evolutionary innovations, over the time scale of microevolutionary events, physiological stress mainly guards the genome and ensures evolutionary stasis by stabilizing selection and maintaining the diversity of individual niches in the population. This is largely the evolutionary role of physiological stress.