Holarctic Marmots as a factor of Biodiversity.
Rumiantsev V.Yu;, Nikol'skii A.A. & Brandler O.V. eds.,
Abstracts, 3d Conference on Marmots (Cheboksary, Russia, 25-30 August 1997),
Moscow ABF 1997, 216p. : 183.


GROUND DWELLING SCIURIDAE (MARMOTS AND GROUND SQUIRRELS) - THE UNIQUE NATURAL MODEL TO STUDY MORPHO-GENETIC PROCESSES IN REPRODUCTIVE ORGANS


V.N. Rudy*, N.N. Shevljuk**, A.A. Stadnikov**

* State Pedagogical University,
** State Medicine Academy, Orenburg, Russia


Many aspects of reproduction of bobac marmots are still studied insufficiently (Bibikov, 1989; Rymalov, 1994). In spite of numerous articles, concerning marmots, data both on morpho-functional description of reproductive organs and reproductive behaviour are scarce. The same problems are typical for study of reproduction of ground squirrels as well.

The situation is even more paradoxical, as the unique life cycle of these animals (short breeding period, great range of morpho-functional variability of reproductive organs, large size of the animals permitting easy observation, resident character of living) is very suitable for study of morpho-functional features of reproduction. During short periods of spring and summer activity these animals undergo annual morphological and functional changings, which can be compared to the period of maturation in other animals. After breeding season regressing stage is observed in male testicles, as a result microscopic structure of male sex glands of marmots and ground squirrels changes back to the initial condition, typical for embryo testicle. The following stage, stage of rest (dormancy) is quite specific in these animals. Against the background of testicle curved tubules, which structure is similar to embryo stage (including the diameter of curved tubules and condition of spermatogenic epithelium) rather high steroidogenic activity of endocrinocytes is observed in testicles. By the late summer in testicles of these animals progressive stage of sex gland cycle starts - the stage of preparing to reproduction. The stage is enough specific too. Start of spermatogenesis in curved tubules comes up only to stage of maturation, matured spermatozoids are not formed in marmot and ground squirrel testicles before hibernation.

Probably, final stage of spermatogenesis - forming period - goes in marmots and ground squirrels in the late stage of hibernation. Unfortunately, we have neither literature data, no our own data on this period. Testicle condition during hibernation is not studied in these animals. Such data may appear very valuable, as they could result in generation of the idea of annual fluctuation (circannual rhythm) of morpho-functional parameters of reproductive organs and general reproductive strategy of these animals.

Study of testicles in marmots and ground squirrels permit to obtain data for study of histo-genetic transformations (cell proliferation, differentiation, genetically determined cell death, etc.).

Thus, complex research of all above mentioned aspects of reproduction would result in generation of more complete idea of ground dwelling Marmotinae reproduction, which is very important for economical use of particular marmot species.


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