Abstract
The role of hybridization through multi-specific synchronous spawning in the evolution of reef-building corals has been discussed since the 1990s, particularly for the genus Acropora. However, F1 hybrids have been reported as common in only one case in the Caribbean, with no evidence of mechanisms that would allow continuous reproduction of the hybrids. In this study, we report for the first time the fecundity of two F1 hybrid colonies produced experimentally from two Indo-Pacific species, A. intermedia and A. florida. These F1 hybrids spawned at the same time as the parental corals. Backcrossing and F1 hybrid crossing were successful in both directions. Furthermore, more than 90% self-fertilization was achieved in an F1 hybrid, although it was negligible in the parental corals. While it is possible that the F1 hybrid was a chimera, these results suggest that some products of interspecific hybridization may persist as the offspring of self-fertilizing F1 hybrids.
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References
Barrett SC (2003) Mating strategies in flowering plants: the outcrossing–selfing paradigm and beyond. Proc R Soc Lond B Biol Sci 358:991–1004
Fogarty ND (2012) Caribbean acroporid coral hybrids are viable across life history stages. Mar Ecol Prog Ser 446:145–159
Harrison PL (2011) Sexual reproduction of scleractinian corals. In: Dubinsky Z, Stambler N (eds) Coral reefs: an ecosystem in transition. Springer, New York, pp 59–85
Hatta M, Fukami H, Wang W, Omori M, Shimoike K, Hayashibara T, Ina Y, Sugiyama T (1999) Reproductive and genetic evidence for a reticulate evolutionary history of mass-spawning corals. Mol Biol Evol 16:1607–1613
Isomura N, Iwao K, Fukami H (2013) Possible natural hybridization of two morphologically distinct species of Acropora (Cnidaria, Scleractinia) in the Pacific: fertilization and larval survival rates. PLoS One 8:e56701
Iwao K, Omori M, Taniguchi H, Tamura M (2010) Transplanted Acropora tenuis (Dana) spawned first in their life 4 years after culture from eggs. Galaxea 12:47
Knowlton N, Jackson JBC (1993) Inbreeding and outbreeding in marine invertebrates. In: Thornhill N (ed) The natural history of inbreeding and outbreeding. University of Chicago Press, Chicago, pp 200–249
Nozawa Y, Isomura N, Fukami H (2015) Influence of sperm dilution and gamete contact time on the fertilization rate of scleractinian corals. Coral Reefs 34:1199–1206
Omori M (2005) Success of mass culture of Acropora corals from egg to colony in open water. Coral Reefs 24:563
Omori M, Iwao K (2014) Methods of farming sexually propagated corals and outplanting for coral reef rehabilitation; with list of references for coral reef rehabilitation through active restoration measure. Akajima Marine Science Laboratory, Okinawa
Puill-Stephan E, Willis BL, van Herwerden L, van Oppen MJH (2009) Chimerism in wild adult populations of the broadcast spawning coral Acropora millepora on the Great Barrier Reef. PLoS One 4:e7751
Richards ZT, van Oppen MJH, Wallace CC, Willis BL, Miller DJ (2008) Some rare Indo-Pacific coral species are probable hybrids. PLoS One 3:e3240
Sawada H, Morita M, Iwano M (2014) Self/non-self-recognition mechanisms in sexual reproduction: new insight into the self-incompatibility system shared by flowering plants and hermaphroditic animals. Biochem Biophys Res Commun 450:1142–1148
Vollmer SV, Palumbi SR (2002) Hybridization and the evolution of reef coral diversity. Science 296:2023–2025
Wallace CC (1999) Staghorn corals of the world: a revision of the genus Acropora. CSIRO Publishing, Melbourne
Willis BL, van Oppen MJH, Miller DJ, Vollmer SV, Ayre DJ (2006) The role of hybridization in the evolution of reef corals. Annu Rev Ecol Evol Syst 37:489–517
Acknowledgments
We are grateful to three anonymous reviewers for their help and constructive comments. We thank M. Omori and S. Hosaka for enthusiastic support to the present study; S. Takahashi, Y. Oku, H. Shirahata, A. Toho, and S. Kitanobo for assistance with crossing experiments; and N. Knowlton for reviewing the manuscript and giving useful comments. This study was supported by JSPS KAKENHI (#26440225) to N.I.
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Communicated by Biology Editor Dr. Mark J. A. Vermeij
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Isomura, N., Iwao, K., Morita, M. et al. Spawning and fertility of F1 hybrids of the coral genus Acropora in the Indo-Pacific. Coral Reefs 35, 851–855 (2016). https://doi.org/10.1007/s00338-016-1461-9
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DOI: https://doi.org/10.1007/s00338-016-1461-9