Periodic spawning of three types of the ascidian,Halocynthia roretzi (Drasche), under continuous light conditions
✍ Scribed by Numakunai, Takaharu ;Hoshino, Zen-Ichiro
- Publisher
- John Wiley and Sons
- Year
- 1980
- Tongue
- English
- Weight
- 437 KB
- Volume
- 212
- Category
- Article
- ISSN
- 0022-104X
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✦ Synopsis
Abstract
We observed the spawning behavior of three types of H. roretzi kept under continuous light conditions for a 2 week period. Three different spawning behaviors were observed. Type A spawned both under continuous light and continuous darkness. Type B spawned under continuous light and Type C under continuous dakness. All these type spawned twice a day. In contrast, animals under the natural light cycle spawn once a day. We propose that there are at least two periodic factors that define their spawning times. Spawning seasons were prolonged or advanced several months by keeping animals in cold sea water or in warm sea water. Their spawning times remained basically unchanged, although to some extent (depending upon the sea water temperature) they changed.