Genetic evidence for mixed modes of reproduction in the coral Pocillopora damicornis and its effect on population structure

Abstract

Allozyme electrophoresis of 6 polymorphic loci was used to estimate the relative importance of sexual and asexual reproduction in Western Australian populations of the coral Pocillopora damicornis and to infer the extent of larval dispersal between them. Evidence for considerable yet variable amounts of asexual reproduction was found. Only 96 of a total of 644 coral heads sampled were apparently of sexual origin, and 8 of the 10 populations showed large departures from HardyWeinberg equilibria as a result of both heterozygote excesses and deficits. Multi-locus genotypic diversity values were significantly less than expected for 8 of the 10 populations sampled, but the magnitude of these values varied enormously (range G o :G e = 0.072 to 0.770). Significant genetic subdivision among populations was found (F ST = 0.360) that was not attributable to different reefs (F RT = 0.080), habitat type (F HT = -0.039), or geographical distance between populations (Mantel test p = 0.129). However, pairwise comparisons revealed significant genetic subdivision at all spatial scales sampled. Furthermore, this subdivision was largely maintained even among populations of putative sexual origin (F ST = 0.175). These results are consistent with the notion that reefs at Ningaloo and the Houtman Abrolhos Islands are primarily self-seeding and that asexually derived recruits have a considerable effect on local abundance and population structure.

Marginal coral populations: the densest known aggregation of Pocillopora in the Galápagos Archipelago is of asexual origin

“…Ameiotic planulae have, theoretically, the same dispersal potential as their sexually produced counterparts and thus could be transported further than fragments (Stoddart, 1983). Several clones of the coral P. damicornis were found distributed over 8 reefs in Hawaii (Stoddart, 1983) and over 800 km in Australia (Whitaker, 2006). However, we did not find evidence of genet PD100 outside of the larva pools despite searching habitat around Isabela that previously had been settled by Pocillopora.…”

“…However, correlating age and size is complicated in fragmenting corals such as Pocillopora damicornis. In addition to asexual reproduction via fragmentation, P. damicornis can produce asexual (ameiotic) (Yeoh and Dai, 2010) as well as sexual planula larvae leading to populations of mixed asexual and sexual origin, e.g., in the Western Australia, Panama, Hawaii and the Ryukyu Islands (Stoddart, 1984;Richmond, 1987;Adjeroud and Tsuchiya, 1999;Whitaker, 2006). In contrast, on the Great Barrier Reef and Lord Howe Island reef, sexual reproduction dominates (Benzie et al, 1995;Ayre et al, 1997;Ayre and Miller, 2004;Miller and Ayre, 2004).…”

Contrasting clonal structure among Pocillopora (Scleractinia) communities at two environmentally distinct sites in the Gulf of California

“…Populations of Pocillopora spp from east coast of Africa (Ridgway et al 2001), Western Australia (Stoddart 1984b(Stoddart , 1984cWhitaker 2006), Indonesian Archipelago (Starger et al 2010); the Great Barrier Reef (GBR) (Benzie et al 1995;Ayre et al 1997;Sherman et al 2006), Lord Howe Island , Japan (Adjeroud and Tsuchiya 1999), Taiwan (Yeoh and Dai 2010) Hawaii (Stoddart 1984a), and eastern (Combosch and Vollmer 2011) and south Pacific (Magalon et al 2005) show varying patterns of genetic diversity, genotypic diversity, and/ or connectivity (Table 3). While sampling protocols in these studies were not designed to explicitly assess clonal structure (Baums et al 2006), populations at certain locations were highly clonal (Stoddart 1984a;Yeoh and Dai 2010).…”

“…In Florida, the northernmost limit of the distribution of Acropora palmata, stands of this species are highly clonal compared to other more central populations in the Caribbean (Baums et al 2006). Studies on the relative influence of sexual and asexual reproduction have often focused on the branching species of the common coral genus Pocillopora (Stoddart 1983(Stoddart , 1984aAyre et al 1997;Adjeroud and Tsuchiya 1999;Ridgway et al 2001;Miller and Ayre 2004;Whitaker 2006;Yeoh and Dai 2010). Clonality measured among and between populations of these corals varies widely throughout the Indo-Pacific and such differences may be attributed to particular environmental conditions and/or disturbance frequency (Ayre et al 1997;Baird et al 2009).…”

Human-mediated transport determines the non-native distribution of the anemone Nematostella vectensis, a dispersal-limited estuarine invertebrate

“…First, many sessile invertebrates are capable of asexual reproduction (Jackson et al 1985), and patterns of population growth and spatial expansion may reflect contributions of both sexual and asexual increase. Asexual reproduction is known to have significant effects on the population structure of reefbuilding corals (Stoddart 1984, Miller & Ayre 2004, Whitaker 2006, Foster et al 2007) and other anthozoans (Ayre 1984, Shaw 1991, Sherman & Ayre 2008, as well as some other invertebrate taxa (Zilberberg et al 2006). However, the potential effect of reproductive plasticity on invasion dynamics in marine invertebrate taxa remains understudied.…”