Ecological Analysis of Spleen Hypertrophy in Cyclomorphic Rodents Taking into Account the Type of Ontogeny

The functional approach at the level of physiological functional groups (PFGs) reflecting two types of ontogeny was used to analyze spleen hypertrophy in five species of rodents. In addition to a wide variation of spleen weight, its hypertrophy was observed: in bank voles (Clethrionomys glareolus), the spleen weight was as great as 3.5 g versus the normal value of 100–150 mg. The variation range of the relative spleen weight was estimated. For example, in the dominant species, C. glareolus, this range was considerable (from 2 to 125). A distinct relationship with the types of animal ontogeny was revealed. The genus specificity of the phenomenon—its occurrence in three species of Clethrionomys voles and absence in Microtus voles and mice—was determined in the study region. The animals with normal and hypertrophied spleens did not differ from each other significantly in their vital activity (at least, with respect to the parameters studied). The voles with hypertrophied spleens normally reproduced, and the hypertrophy was asymptomatic. These findings suggest that the populations have adapted to a damaging factor (or factors) in the course of a prolonged coevolution. This parameter is regarded as the indicator of the presence of a damaging factor in the population.     

Alternative Types of Ontogeny in Cyclomorphic Rodents and Their Role in Population Dynamics: An Ecological Analysis

Two alternative ontogenetic pathways regularly effected in the populations of small mammals are analyzed as a manifestation of developmental multiversality. The types of ontogeny in rodents are characterized. These data are reflected in the concept of the functional approach. Multiversality of development in plants and animals is considered. Based on the results of long-term (26-year) observations on the natural populations of six rodent species, the dynamics of relationships between the types of ontogeny, abundance, and basic population parameters are analyzed using an example of a background species (Clethrionomys glareolus). A trigger mechanism of switching to a certain type of ontogeny, the role of environmental factors in actuating this mechanism, and the role of the genotype as a basis of multivalence are discussed. The existence of two developmental variants is regarded as a basis for functional rearrangements providing for a high flexibility of population responses and as a mechanism of population regulation determining the dynamics of rodent fauna. An adaptive population response to a board spectrum of influences, including anthropogenic damage, depends not only on the type and strength of the influence, but also on the functional structure of the population. The concepts described in the paper may explain the significance of critical periods in the life of populations.     

The wild ancestors of domestic animals as a neglected and threatened component of biodiversity

Domestic animals have immense economic, cultural, and practical value and have played pivotal roles in the development of human civilization. Many domesticates have, among their wild relatives, undomesticated forms representative of their ancestors. Resurgent interest in these ancestral forms has highlighted the unclear genetic status of many, and some are threatened with extinction by hybridization with domestic conspecifics. We considered the contemporary status of these ancestral forms relative to their scientific, practical, and ecological importance; the varied impacts of wild–domestic hybridization; and the challenges and potential resolutions involved in conservation efforts. Identifying and conserving ancestral forms, particularly with respect to disentangling patterns of gene flow from domesticates, is complex because of the lack of available genomic and phenotypic baselines. Comparative behavioral, ecological, and genetic studies of ancestral-type, feral, and domestic animals should be prioritized to establish the contemporary status of the former. Such baseline information will be fundamental in ensuring successful conservation efforts.