Zygote

Research Article

In vitro fertilization efficiency in coral Acropora digitifera

Akira Iguchia2a3a4, Masaya Moritaa5, Yuichi Nakajimaa4a5, Akira Nishikawaa2a3 and David Millera1a2a3 c1

a1 ARC Centre of Excellence for Coral Reef Studies, James Cook University, Australia, Townsville, Queensland, 4811, Australia.

a2 ARC Centre of Excellence for Coral Reef Studies, James Cook University, Australia, Townsville, Queensland, 4811, Australia.

a3 Comparative Genomics Centre, Molecular Science Building, James Cook University, Australia, Townsville, Queensland, 4811, Australia.

a4 Graduate School of Engineering and Science, University of the Ryukyus, Nishihara, Okinawa, 903–0213, Japan.

a5 Sesoko Station, Tropical Biosphere Research Center, University of the Ryukyus, 3422, Sesoko, Motobu, Okinawa, 907–0227, Japan.

Summary

We performed fertilization experiments with Acropora digitifera, which is one of the dominant scleractinian corals in the Ryukyu Archipelago, Japan, to determine optimal conditions for in vitro manipulations. Our result suggests that conspecific fertilization is essentially complete within 30 min under the experimental conditions used in usual fertilization experiments in corals. Previous in vitro experiments (1 × 105–106 sperm/ml, 4–8 h) are likely to have overestimated the efficiency of fertilization of Acropora spp. in the field. Therefore, we suggest that incubation periods shorter than those used to date (i.e. complete exclusion of sperm 1 h after their addition) would be more appropriate for the estimation of fertilization rates in corals.

(Received October 14 2008)

(Accepted December 09 2008)

Correspondence:

c1 All correspondence to David Miller. ARC Centre of Excellence for Coral Reef Studies, James Cook University, Australia, Townsville, Queensland, 4811, Australia. Tel: +61 747 814473. Fax: +61 747 816078. e-mail: david.miller@jcu.edu.au

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