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The Formation of New Characteristics in the Life Cycle of the Marsh Frog (Rana ridibunda) in Thermal Pondsстатья
- Авторы: Fominykh A.S., Lyapkov S.M.
- Журнал: Biology Bulletin Reviews
- Том: 2
- Номер: 3
- Год издания: 2012
- Издательство: Pleiades Pub.
- Местоположение издательства: Tortola, British Virgin Islands, British Virgin Islands
- Первая страница: 211
- Последняя страница: 225
- Аннотация: The longterm dynamics of the marsh frog population inhabiting a small thermal pond serving as a sedimentation basin for discharged waters of the Nizhnii Tagil Iron and Steel Plant was studied using group marking of metamorphs and recapturing. Three groups of individuals were singled out depending on metamorphosis completion: the early ones (group I); the middle ones (group II); and the late ones overwintering as tadpoles and completing their metamorphosis in May of the following year (group III). Upon the comple tion of metamorphosis, the individuals from group I were significantly larger than those from group II. Nevertheless, the individuals of these two groups were significantly smaller than those from group III. After the first wintering, the immature individuals from group I were significantly larger than the individuals from group II and the metamorphs (after the first wintering) from group III. The growth rate in the latter was higher than in groups I and II. These distinctions were observed in both immature and adult individuals. Over the period from metamorphosis completion until the end of the first wintering, the survival rate was significantly higher in the individuals of group I, while it was almost the same in groups II and III. The maximum survival rate among adults was observed in the individuals from group III, with the minimum survival rate registered for group II. These distinctions recurred in each of the age classes up to the fourth wintering. Nevertheless, the maximum survival rate for the age classes that overwintered four and five times was observed in group II. This fact can be viewed as compensation for a rather low survival rate among immature individuals from this group. All the winterings of the Rana ridibunda tadpoles covered in the literature (except in other thermal water bodies) correspond to rare deviations from normal ontogenesis. Therefore, the numerous group of overwintering tadpoles found in every generation is a new adaptation, the essence of which lies in decreased competition among the groups of tadpoles under a yearround use of the resources of the thermal pond, which was characterized by a high productivity. The advantageous body sizes and growth rates in tadpoles and metamorphs of the immature and adult individuals from group III indicate that the strategy of this group remains successful even when metamorphosis is complete. The reason for this lies in the unusually large body sizes in metamorphs, which provide a higher postmetamorphic survival rate and greater female fecundity.
- Добавил в систему: Ляпков Сергей Марленович