Untersuchungen zur Jahresperiodik der Fortpflanzung beim miinnlichen Kammolch, Triturus cristatus cristatus Laurenti, in Abhiingigkeit von Photoperiode und Wassertemperatur

Abstract

Under natural photoperiodic conditions and natural water temperatures, the spermatogenesis and testis cycle of Triturus cristatus cristatus exhibits a clear annual periodicity with one reproductive period extending from the end of April to the middle of June. This cycle can be divided into three different phases: 1 ) progression with expulsion of ripe sperma and subsequent spermatocytogenesis ; 2) regeneration with spermiohistogenesis and maximum testis' weight; 3) gonadal resting phase. An advance of gonadal activity in winter with premature expulsion of mature sperm a was only possible in LD 16 : 8 at 20 ± 1°C water temperature; complete spermatogenesis can occur after the middle of February.In the winter and summer, water temperature of 11 ± 1°C combined with long days, LD 12 : 12 , or with short days prevent any gonadal activity. Therefore, water temperature of 20 ± 1°C, combined with long days, are a prerequisite for adequate hypothalamus-hypophysis-gonad-activity.In a year's study with LD 16 : 8 at 20 ± 1°C water temperature, a more or less pronounced spermiahistogenetic activity without expulsion of sperma was observed.