Settlement-competency Period of Planulae and Genetic Differentiation of the Scleractinian Coral Acropora digitifera(Animal Diversity and Evolution)
スポンサーリンク
概要
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Broadcast-spawning corals expel eggs and sperm, and the fertilized eggs develop into planulae in the water column. As these sessile corals generally disperse during the planktonic larval stage, their larval characteristics (e.g., survival and settlement rates) are thought to be important for their dispersal. Although some studies of coral larval dispersal have focused on the maximum time that larvae can remain viable and settle, the relevance of this maximum settlement competency period for long distance dispersal remains unclear. To examine the relationship between competency periods and genetic differentiation, we performed laboratory experiments to investigate settlement rates of planulae and determine the degree of genetic differentiation in Acropora digitifera in the Ryukyu Archipelago, southern Japan. In addition, we compared our findings to published data for A. tenuis, which was studied using our methods. Our results indicated that the maximum settlement competency period was lower in A. digitifera planulae (54 days) than in A. tenuis (69 days) planulae. The mean survival rates at 45 days and 59 days after spawning were less than 10%. Furthermore, percentages of planulae that remained viable and settle at 30 days after spawning (survival rate × settlement rates at 30 days) were approximately 18% and 25% in A. digitifera and A. tenuis, respectively. By contrast, gene flow (N_em: number of migrations per generation) was significantly higher in A. digitifera (7.8 to 41.4) than in A. tenuis (3.1 to 22.5). These results indicate that the settlement competency period and survival rates are unlikely to be robust predictors of gene flow. Overall, we detected significant genetic differentiation between Kerama and Okinawa in A. digitifera. As direct observation of planula dispersal between Kerama and Okinawa has been reported, we concluded that genetic mixing is not complete, but that some localized planulae may disperse from Kerama to Okinawa via a specific current depending on reef or locality.
- 社団法人日本動物学会の論文
- 2005-04-25
著者
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SAKAI Kazuhiko
Sesoko Station, Tropical Biosphere Research Center, University of the Ryukyus
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Nishikawa Akira
Sesoko Station, Tropical Biosphere Research Center, University of the Ryukyus
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Sakai Kazuhiko
Sesoko Station Tropical Biosphere Res. Center Univ. Of The Ryukyus
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Nishikawa Akira
Comparative Genomics Centre Molecular Sciences Bldg 21 James Cook Univ.
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Nishikawa Akira
Sesoko Station Tropical Biosphere Research Center University Of The Ryukyus
関連論文
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- Genetic Variation and Gene Flow of Broadcast Spawning and Planula Brooding Coral, Goniastrea aspera (Scleractinia) in the Ryukyu Archipelago, Southern Japan(Animal Diversity and Evolution)
- Settlement-competency Period of Planulae and Genetic Differentiation of the Scleractinian Coral Acropora digitifera(Animal Diversity and Evolution)
- Novel and cross-species amplifiable microsatellite markers in two Acropora species
- Seasonal changes in reproductive and physical condition, sexual dimorphism, and male mating tactics in the jewelled blenny Salarias fasciatus
- Intraspecific Contact and Egg Production in the Massive Coral Goniastrea Aspera in Okinawa, Subtropical Japan(Ecology)
- Delayed Maturation in the Colonial Coral Goniastrea aspera(Scleractinia):Whole-Colony Mortality, Colony Growth and Polyp Egg Production
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