Synchronous spawning of host sea anemones (original) (raw)
Related papers
Invertebrate Reproduction & Development, 2007
As the sea anemones, Entacmaea quadricolor and Heteractis crispa, provide essential habitat for obligate symbiotic anemonefish, knowledge of their reproductive biology is crucial to their effective management and conservation. This paper provides the first detailed information on the spawning times, behaviour and mode of gamete release for these host anemone species. Anemones were collected from subtropical reefs in the Solitary Islands Marine Park, eastern Australia, and monitored in outdoor flow-through seawater tanks from 2003 to 2005. Sexually reproductive anemones were either male or female, releasing their gametes into the water column for external fertilisation and development. Spawning of both sexes was predominately synchronous and was restricted to a few nights each year during the austral summer and autumn. Males generally began to release gametes prior to females, suggesting that sperm or some associated product may trigger the females to spawn. Sperm were commonly released in milky white streams or clouds, whereas eggs were released singly or in large masses. Reproductive seasonality and synchrony of gamete release suggests that spawning in both species is coordinated by similar responses of individuals to a range of environmental factors such as seawater temperature, photoperiod and lunar cycles. Incorporating knowledge of the sexual reproductive biology of host sea anemones into management and conservation programs could help ensure the viability of their populations and their resident anemonefish.
Plankton and Benthos Research
This is the first record of an epibiotic association between an acontiate sea anemone and a fish. We collected unidentified epibiotic sea anemones living on the necto-benthic fish Inimicus japonicus (Cuvier 1829) from the Seto Inland Sea, Japan. Molecular analyses revealed that the anemones were most closely related to Verrillactis paguri (Stimpson in Verrill 1869) sensu England (1971), which has a mutualistic relationship with hermit crabs. Therefore, we tentatively assigned the collected species as Verrillactis sp. (Actiniaria: Sagartiidae). This finding of sea anemones using fish as substrate is unprecedented. Future research into this relationship to determine if this is an incidental occurrence or facultative symbiosis is warranted. Our findings contribute to a wider understanding of symbiosis in sea anemones.
Plankton and Benthos Research, 2022
This is the first record of an epibiotic association between an acontiate sea anemone and a fish. We collected unidentified epibiotic sea anemones living on the necto-benthic fish Inimicus japonicus (Cuvier 1829) from the Seto Inland Sea, Japan. Molecular analyses revealed that the anemones were most closely related to Verrillactis paguri (Stimpson in Verrill 1869) sensu England (1971), which has a mutualistic relationship with hermit crabs. Therefore, we tentatively assigned the collected species as Verrillactis sp. (Actiniaria: Sagartiidae). This finding of sea anemones using fish as substrate is unprecedented. Future research into this relationship to determine if this is an incidental occurrence or facultative symbiosis is warranted. Our findings contribute to a wider understanding of symbiosis in sea anemones.
Coral Reefs, 2004
The ecological performance of the sea anemone Heteractis magnifica was examined during a 36-month experiment with respect to season and the presence and numbers of a mutualist (orange-fin anemonefish Amphiprion chrysopterus). Anemones primarily grew during the autumn, with most asexual reproduction occurring in winter; mortality was not strongly seasonal. Individual growth rates did not differ between anemones harboring one or two anemonefish, but these rates were three times faster than for anemones lacking Amphiprion. Anemones with two anemonefish had the highest fission rate, whereas those without anemonefish had the lowest. By contrast, anemones that were not defended by anemonefish suffered higher-than-expected mortality. As a consequence, anemones with two Amphiprion had the greatest net increase in surface area, and those lacking anemonefish had a negligible gain that was statistically indistinguishable from zero after three years. Anemonefish not only enhanced anemone survivorship as previously believed, they also fostered faster growth and more frequent asexual reproduction.
Modes of reproduction in sea anemones (Cnidaria, Anthozoa)
Biology Bulletin, 2011
The data on different modes of reproduction in sea anemones are generalized. These animals can reproduce sexually in an ordinary way or by parthenogenesis. Asexual reproduction occurs in various forms, such as transverse and longitudinal fission, pedal laceration, or autotomy of tentacles. Specific features of dif ferent variants of sexual and asexual reproduction and their combinations in sea anemones from different habitats of the World Ocean are discussed.
Larval settlement and juvenile development of sea anemones that provide habitat for anemonefish
Marine Biology, 2008
Sea anemones that host obligate symbiotic ane-moneWsh are ecologically important throughout many coral reef regions of the Indo-PaciWc. This study provides the Wrst quantitative data on larval settlement rates and juvenile development of two species of host sea anemone, Heteractis crispa and Entacmaea quadricolor. Larvae were reared from broadcast spawned gametes of sexually reproductive male and female anemones collected from the Solitary Islands Marine Park, NSW, Australia. Prior to the start of the experiments, H. crispa larvae were reared for 3 days after spawning in March 2004 and E. quadricolor larvae were reared for 4 days after spawning in February 2005. Larval settlement onto biologically conditioned terracotta tiles in outdoor Xow-through seawater aquaria was Wrst recorded 4 days after spawning for H. crispa and 5 days after spawning for E. quadricolor. Peak settlement occurred 10 days after spawning, with a mean of 33.4 and 50.3% of the original groups of 350 larvae in replicate tanks settling for H. crispa and E. quadricolor, respectively. Tentacles arose as outpocketings of the oral region, at Wrst appearing as small rounded buds. These buds elongated to form long, thin, tapering tentacles in H. crispa, whereas E. quadricolor tentacles had slight bulbs below the tips. Juvenile anemones, especially H. crispa, were found to have very diVerent colouration and markings when compared with adult anemones, and therefore the descriptions and images provided here will enable correct identiWcation of juvenile recruits.
Phylogenetic relationships among the clownfish-hosting sea anemones
2019
The clownfish-sea anemone symbiosis has been a model system for understanding fundamental evolutionary and ecological processes. However, our evolutionary understanding of this symbiosis comes entirely from studies of clownfishes. A holistic understanding of a model mutualism requires systematic, biogeographic, and phylogenetic insight into both partners. Here, we conduct the largest phylogenetic analysis of sea anemones (Order Actiniaria) to date, with a focus on expanding the biogeographic and taxonomic sampling of the 10 nominal clownfishhosting species. Using a combination of mtDNA and nuDNA loci we test 1) the monophyly of each clownfish-hosting family and genus, 2) the current anemone taxonomy that suggests symbioses with clownfishes evolved multiple times within Actiniaria, and 3) whether, like the clownfishes, there is evidence that host anemones have a Coral Triangle biogeographic origin. Our phylogenetic reconstruction demonstrates widespread poly-and para-phyly at the family and genus level, particularly within the family Stichodactylidae and genus Sticodactyla, and suggests that symbioses with clownfishes evolved minimally three times within sea anemones. We further recover evidence for a Tethyan biogeographic origin for some clades. Our data provide the first evidence that clownfish and some sea anemone hosts have different biogeographic origins, and that there may be cryptic species of host anemones. Finally, our findings reflect the need for a major taxonomic revision of the clownfish-hosting sea anemones.
The Biological Bulletin, 2022
Here we describe Stylobates calcifer sp. nov. (Cnidaria, Actiniaria, Actiniidae), a new carcinoecium-forming sea anemone from the deep-sea floor of Japan. Stylobates produces a carcinoecium that thinly covers the snail shells inhabited by host hermit crabs Pagurodofleinia doederleini. The new species is distinct from other species by the shape of the marginal sphincter muscle, the distribution of cnidae, the direction of the oral disk, and host association. The species' novelty is supported by the data of its mitochondrial genes 12S, 16S, and COIII and nuclear genes 18S and 28S. Also, we conducted behavioral observation of this new species, focusing on the feeding behavior and interaction with the specific host hermit crab. Our observations suggest that this sea anemone potentially feeds on the suspended particulate organic matter from the water column or the food residuals of hermit crabs. When the host's shell changed, intensive manipulation for transference of S. calcifer sp. nov. was recorded. However, although the hermit crab detached and transferred the sea anemone to the new shell after shell change, the sea anemone did not exhibit active or cooperative participation. Our data suggest that the sea anemone may not produce a carcinoecium synchronously to its host's growth, contrary to the anecdotal assumption about carcinoecium-forming sea anemones. Conversely, the host hermit crab's growth may not depend entirely on the carcinoecium produced by the sea anemone. This study is perhaps the first observation of the behavioral interaction of the rarely studied carcinoecium-forming mutualism in the deep sea.
Ethology, 2010
Many reet fish have strong microhabitat preferences when they settle to the juvenile pop. ulation, and choices at this time may influence fish survival. This is exemplified in anemonefishes (Family: Pomacentridae) thaI exhibit obligate symbiotic relationships willi a restricted range of sea anemone species. This study examined how juvenile anemonefish Amphiprion melanopus select their host, and whether recognition and selection are mediated by an imprinting.like mechanism. Specifically, we experimentally examined the host-selection made by A. melanopus thaI had been reared under conslant conditions, but whose embryos had received 1 of 3 treatments: (1) in contact willi a known natural host sea anemone, Entacmaea quadricolor; (2) in contact with the sea anemone Heteractis malu, which is not a host for A. melanopus in nature, but is a host for anemonefish of other species; and (3) without a sea anemone (or chemicai cues released from sea anemones) at any life stage. Our study shows thaI olfaction, not vision, is used by juvenile A. melanopus to recognize host anemones. Furthermore, the choice of a settlement site for juvenile A. melanopus is strongly influenced by events that occur early in development, prior to the dispersal of larvae from their natal site. We suggest that juvenile A. melanopus possess an innate preference for E. quadricolor, a preference that is enhanced by imprinting. Interestingly, it was not possible to imprint A. melanopus larvae to the non-host sea anemone H. maJu, which suggests thaI anemonefish host-imprinting may be rather restricted.