|
Vol. 51 No. 2, 2012
Larval Development of Fertilized “Pseudo-Gynodioecious” Eggs Suggests a Sexual Pattern of Gynodioecy in Galaxea fascicularis (Scleractinia: Euphyllidae)
Shashank Keshavmurthy1, Chia-Min Hsu1,2, Chao-Yang Kuo1, Vianney Denis1, Julia Ka-LaiLeung1,3, Silvia Fontana1,4, Hernyi Justin Hsieh5, Wan-Sen Tsai5, Wei-Cheng Su5, and Chaolun Allen Chen1,2,6,7,*
1Biodiversity Research Center, Academia Sinica, Nangang, Taipei 115, Taiwan
2Institute of Oceanography, National Taiwan Univ., Taipei 106, Taiwan
3Institute of Life Sciences, National Taiwan Normal Univ., Taipei 106, Taiwan
4Univ. of Milan-Bicocca, Piazza della Scienza 2, Milan 20126, Italy
5Penghu Marine Biological Research Center, Makong 880, Taiwan
6Institute of Life Science, National Taitung Univ., Taitung 950, Taiwan
7Taiwan International Graduate Program (TIGP)- Biodiversity, Academia Sinica, Nangang, Taipei 115, Tawian
Shashank
Keshavmurthy, Chia-Min Hsu, Chao-Yang Kuo, Vianney Denis, Julia
Ka-LaiLeung, Silvia Fontana, Hernyi Justin Hsieh, Wan-Sen Tsai,
Wei-Cheng Su, and Chaolun Allen Chen (2012) Galaxea fascicularis possesses a unique sexual pattern, namely “pseudo-gynodioecy”, among scleractinian corals. Galaxea fascicularis
populations on the Great Barrier Reef, Australia are composed of female
colonies that produce red eggs and hermaphroditic colonies that produce
sperm and white eggs. However, white eggs of hermaphroditic colonies
are incapable of being fertilized or undergoing embryogenesis. In this
study, the reproductive ecology and fertilization of G. fascicularis
were examined in Chinwan Inner Bay, Penghu, Taiwan in Apr.-June 2011 to
determine the geographic variation of sexual patterns in G. fascicularis.
Synchronous spawning of female and hermaphroditic colonies was observed
between 17:30 and 20:00 (1 h after sunset) between 24-28 May 2011 (7-11
nights after the full moon in May), and at same times between 22-24
June 2011 (6-8 nights after the full moon in June). Red eggs were
significantly larger than white eggs, although both types of eggs had a
distinct nucleus, which was located at the edge of the eggs, suggesting
that they were in the final stage of maturation and ready to release
gametes. Crossing experiments showed that both white and red eggs could
be fertilized in vivo, and
they synchronously developed into swimming larvae, suggesting that
instead of being pseudo-gynodioecious, the sexual pattern of G. fascicularis is gynodioecious.
Key words: Gynodioecy, Pseudo-gynodioecy, Galaxea fascicularis, Reproductive mode, Synchronous spawning.
*Correspondence: Tel: 886-2-27899549. Fax: 886-2-27858059. E-mail:cac@gate.sinica.edu.tw
|
