东方蝾螈繁殖生态的研究

STUDIES ON THE BREEDING ECOLOGY OFCynops orientalis

本文报道东方蝾螈(Cynops orientalis)的繁殖生态,内容有精巢分叶、精子形态、怀卵量、性征、性比、求偶、交配、纳精、产卵及孵化等,并对产卵场中性比的周年变化、精包形态、精子存活力及与蓝尾蝾螈的种间差异进行了观察和讨论。

1. Cynops orientalis is distributed on hilly lands or low mountain areas, and often spawns in the cold still ponds, wells, terraced fields and ditches. Eggs are deposited on the leaves or the adventitious roots of some aquatic herbs.2. A lot of oblique and forward lines on the semi-elliptic swelling cloaca area of the mature male can be seen, while the cloaca area of the female has no appearent protrusion, on which there are radiating lines.3. Of the 482 mature newts collected during the three years, their sex ratio (: ) is 1 : 2.0. The annual total sex tatio in 1988 is 1 : 2.3, but about 1 : 1.5 during the breeding seasen.4. Cynops orientalis in the field in Changsha region begins to spawn in the last or second of May, not prior to that of newts in captivity. The spawning period is from the second decade of March to the first decade of July. The average number of daily spawning is 2.8 ( 1-18 ) . The average number of annual spawning is 96.1 ± 62.4 (10-263) . The peak of spawning is from the second decade of April to the last decade of May. The optimal water temperature for spawning is 15-23 C , the hatching period is generally 13-24 days, the average hatching rate is 74.1 (46 .4-86.8) %, which differs from Cynops cyamtrus (36.3%) .5. The omen of sperm depositing has been observed. The mile white spermatophore deposited by the male at first appears ' S' in shape , wrapped in transparent jelled memberane. One minute later, it condenses into a short cylinder (2.66×1.38mm), at last, becomes into an ellipse or a pentagon (2.76×2.28) . After taking-sperm, the female can spawn normally in 65 days at least, which differs from Cynops cyanurus (14 days) .