A dependence of Siberian fir (Abies sibirica Ledeb.) needle transpiration on the intensity of photosynthetically active radiation (PAR) was studied. Stomatal conductance was estimated indirectly by analyzing the intensities of diffusion of water vapor and CO2 under conditions of controlled PAR. The study was performed using the LI-COR LI-6400XT infrared gas analyzer and opaque chamber for conifers on intact Siberian fir shoots in the middle taiga subzone of the North–East of the European part of Russia. It was demonstrated that in the absence of soil moisture deficiency, constant leaf temperature, and water vapor concentration in the atmosphere, a change in the transpiration intensity is determined by the size of the stomatal pore. An association between stomatal conductance and PAR intensity was established: at PAR intensity equal to zero, the stomatal conductance is minimal, but not zero; with an increase in the PAR intensity to 15 μmol quanta m–2 s–1, the conductance increases to maximal, corresponding to the environmental conditions and remains constant with any changes in the PAR intensity; with a decrease in the PAR intensity to 25 μmol quanta m–2 s–1, the conductance decreases to a level corresponding to zero PAR intensity and given external conditions. Thus, at a constancy of other environmental factors, the stomatal conductance is managed by the PAR intensity; however, the management is not regulatory in nature (at which a certain conductance value corresponds to a given intensity), but is a factor triggering the opening and closing of stomata.
This review examines the unique anatomical, physiological, and behavioral adaptations of vesper bats (Vespertilionidae, Chiroptera) to their environment. These adaptations enable the bats to successfully traverse distances and adapt to conditions of low temperatures and limited energy resources. The results of our own studies and those of specialists in bat biology are summarized and analyzed. This report provides an overview of key events in the annual cycle, as well as features of the reproductive, immune, and hematopoietic systems and fat metabolism in bats compared to other mammalian species.
Diversity of the life cycles of parasites, their living in a wide range of habitats, and interactions with different hosts create many ecological and behavioral situations in which it is difficult to act alone. Among individual and group adaptations that determine the success of parasite transmission and, ultimately, their fitness, aggregation in the external environment and in host populations plays a crucial role. A review and analysis of the behavioral and ecological characteristics of monoxenous (ectoparasitic crustaceans Branchiura, Monogenea) and heteroxenous (Trematoda) parasites allows us to consider aggregation as one of the main factors determining the success of parasite transmission in the “host space.” The success of parasite dispersal and transmission, besides the large number of dispersal larvae produced, is facilitated by a variety of behavioral tactics: active search for hosts, various types of the “sit-and-wait” tactic, aggregation into mono- or polymorphic colonies that increase the availability of the parasite to the next host (predator), and manipulation of the intermediate host’s phenotype that reduces/increases its availability to the predator. Aggregation affects transmission processes at all stages of the life cycle of both mono- and heteroxenous parasites. Along with parasite aggregations, host aggregations play a significant role in the parasite–host system. Host aggregations are not only the result of their self-organization and emergent properties of groups but also a result of manipulation of their behavior by parasites. Aggregation of both parasites and their hosts serves as one of the most important elements of behavioral interactions in the parasite–host system. In parasites, it affects the success of transmission from one host to another; in hosts, it helps them avoid areas with a high risk of infection and maintain a significant portion of their population free of parasites. Aggregations increase stability of the parasite–host system and fitness of its members, helping parasites’ reproduction and transmission; in hosts, such as fish, aggregation provides protection from enemies (predators and parasites) and facilitates foraging and orientation.
The yellow-breasted bunting (Emberiza aureola) is a tropical migrant breeding in taiga zone. Once numerous, the species is on the Red List, and has been classified since 2017 as especially threatened. Biological traits of the species are still not studied enough. The purpose of the present study is to fill in the gap with original data on annual survival and seasonal peculiarities of main events on the breeding grounds and determine whether they can play a role in its unlucky fortune. Using the trapping and marking data on the taiga population in Central Siberia, we carried out the capture–recapture analysis by means of multinomial stochastic modeling. As shown by seasonal dynamics, the phases of the annual cycle allocated to the breeding area are heavily shortened. Some features point out that the dispersal is poorly developed. Annual adult survival reached high values. At the same time, the driver of population fluctuations was the survival rate of 1-year-old individuals. The survival shrunk sharply between 1998 and 2004, so that the population has not recovered thereafter. Based on the obtained data, the connection between the extinction of the population and the recent unprecedented expansion of the species as a probable consequence of the exploitation of rice crops in Southeast Asia is discussed. An excess of food resources in the winter range determined the expansion of the breeding area and significant changes in the annual and life cycle. The sharp depletion of winter resources has led to a modern reduction in numbers and range. To maintain the population of the species, at least local elimination of the causes is necessary. Adaptations acquired during expansion will impede the recovery.
The honey bee Apis cerana plays a significant role in maintaining ecosystem stability through its involvement in pollinating over 500 species of both wild and cultivated plants. Due to its high ecological plasticity, this species is widely distributed across diverse climatic zones, ranging from the tropical regions of Vietnam to the sharply continental areas of Russia’s Primorsky Krai. Under anthropogenic pressures such as urbanization and habitat degradation, the study of the genetic diversity and adaptive potential of A. cerana becomes increasingly important. In this study, polymorphism of the orcokinin A gene (OK-A)—a neuropeptide involved in the regulation of physiological and behavioral responses in bees—has been analyzed. Nucleotide sequences of the OK-A gene were obtained from worker individuals collected from 45 bee colonies representing A. cerana populations from Russia (A. c. ussuriensis), South Korea (A. c. koreana), and Vietnam (A. c. indica). These populations have been shaped by differences in geographic and climatic conditions as well as by genetic-stochastic processes. The OK-A gene showed moderate levels of polymorphism: ten allelic variants were identified among the 45 samples, including two nonsynonymous substitutions within exonic regions (73 tv A/C and 359 ts A/G) and eight variations located in intronic regions. Results of Tajima’s neutrality test (D = –1.90, p < 0.01) suggest possible effects of purifying selection, which may indicate functional significance of the studied gene. The analysis of genetic distances (p-distance) revealed low levels of intraspecific divergence among A. cerana populations (0.004–0.006), whereas interspecific divergence compared to other Apis species, specifically A. mellifera, A. dorsata, and A. florea, was considerably higher (0.097–0.157). Phylogenetic analysis confirmed clear species separation and partial differentiation among A. cerana populations. Some of the identified nucleotide variations, particularly at positions 142 tv (C/G) and 423 tv (G/T), exhibited high discriminatory power and could serve as potential markers for population identification.
