The nature of the symbiosis between Indo-Pacific anemone fishes and sea anemones
TL;DR: The sea anemone-fish symbiosis has generally been considered to benefit only the fish, and thus has been called commensal in nature, but recent field and laboratory observations suggest that this symbiosis more closely approaches mutualism in which both partners benefit to some degree.
Abstract: Under the general heading of symbiosis, defined originally to mean a “living together” of two dissimilar species, exist the sub-categories of mutualism (where both partners benefit), commensalism (where one partner benefits and the other is neutral) and parasitism (where one partner benefits and the other is harmed). The sea anemone-fish (mainly of the genus Amphiprion) symbiosis has generally been considered to benefit only the fish, and thus has been called commensal in nature. Recent field and laboratory observations, however, suggest that this symbiosis more closely approaches mutualism in which both partners benefit to some degree. The fishes benefit by receiving protection from predators among the nematocyst-laden tentacles of the sea anemone host, perhaps by receiving some form of tactile stimulation, by being less susceptible to various diseases and by feeding on anemone tissue, prey, waste material and perhaps crustacean symbionts. The sea anemones benefit by receiving protection from various predators, removal of necrotic tissue, perhaps some form of tactile stimulation, removal of inorganic and organic material from on and around the anemone, possible removal of anemone “parasites”, and by being provided food by some species of Amphiprion.
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TL;DR: In this paper, the authors define mutualism as "an interaction between species that is beneficial to both" since it has both historical priority (311) and general currency (general currency).
Abstract: Elementary ecology texts tell us that organisms interact in three fundamental ways, generally given the names competition, predation, and mutualism. The third member has gotten short shrift (264), and even its name is not generally agreed on. Terms that may be considered synonyms, in whole or part, are symbiosis, commensalism, cooperation, protocooperation, mutual aid, facilitation, reciprocal altruism, and entraide. We use the term mutualism, defined as "an interaction between species that is beneficial to both," since it has both historical priority (311) and general currency. Symbiosis is "the living together of two organisms in close association," and modifiers are used to specify dependence on the interaction (facultative or obligate) and the range of species that can take part (oligophilic or polyphilic). We make the normal apologies concerning forcing continuous variation and diverse interactions into simple dichotomous classifications, for these and all subsequent definitions. Thus mutualism can be defined, in brief, as a -b/qinteraction, while competition, predation, and eommensalism are respectively -/-, -/q-, and -t-/0. There remains, however, the question of how to define "benefit to the
624 citations
Book•
05 Nov 2012
TL;DR: Part 1 Overview of sea anemones: relationships and body plan the hydrostatic skeleton, muscles and mesoglea nervous system sensory receptors Cnidae why aren't there any colonial sea anEMones?
Abstract: Part 1 Overview of sea anemones: relationships and body plan the hydrostatic skeleton, muscles and mesoglea nervous system sensory receptors Cnidae why aren't there any colonial sea anemones?. Part 2 Nutrition: feeding extracellular digestion intracellular digestion translocation and storage symbiosis and unicellular algae photobiology. Part 3 Energy metabolism and respiratory gas exchange: cellular basis of glycolysis and aerobic respiration anaerobic energy metabolism rates of energy metabolism respiratory sunstrates and energetic equivalents of oxygen consumption gas exchange surfaces, their pemeabilty to oxygen and their ventilation factors affecting oxygen consumption. Part 4 Nitrogen excretion and osmotic balance: nitrogen excretion osmocomformity and cellular volume regulation water balance during aerial exposure. Part 5 Growth: units and measurement biochemical composition and energetic equivalents of body weight growth efficiency growth rate do sea anemones grow isometrically or allometrically? indeterminant growth and determinants of body size - the model environmental effects on growth and body size - the reality. Part 6 Reproduction and population structure: sexual reproduction asexual reproduction population structure. Part 7 Biotic interactions: competition ectosymbiosis predation on sea anemones. Appendix: classification of extant anthozoans, particularly sea anemones.
318 citations
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Cites background or methods from "The nature of the symbiosis between..."
...Original description As Actinia aurora, from specimens collected in New Ireland Other names previously used include Radianthus koseirensis (by Mariscal 1970, 1972), Radianthus simplex (by Allen 1972, Moyer 1976), Bartholomea sp. (by Uchida 1975) Diagnostic field characters Tentacles to 50 mm long,…...
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...…specimens collected in the Red Sea Other names previously used include Discosoma giganteum (by Gohar 1948, Schlichter 1968), Stoichactis kenti (by Mariscal 1969, 1970, 1972; Allen 1972, 1973, 1978; Uchida et al. 1975) Diagnostic field characters Deeply-folded oral disc (more pronounced with…...
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...…Actinia magnifica, from specimens collected at Vanikoro, Santa Cruz Islands, New Hebrides Other names previously used include Radianthus ritteri (by Mariscal 1970, 1972, Allen and Mariscal 1971, Allen 1972, 1975, 1978), R. paumotensis (by Allen 1972, Friese 1972), R. macrodactylus (by Uchida et…...
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...Original description As Actinia crispa, from specimens collected in the Red Sea Other names previously used include Radianthus kuekenthali (by Mariscal 1970, 1972, Uchida et al. 1975, Moyer 1976), R. malu (by Allen 1972, 1973, 1975), R. ritteri (by Allen 1978), H. macrodactylum (by Cutress and…...
[...]
...…description As Stichodactyla mertensii, from specimens collected in the easternmost Caroline Islands Names previously used Stoichactis giganteum (by Mariscal 1970, Allen and Mariscal 1971, Allen 1972, 1973, 1975) Diagnostic field characters Oral disc to 1 m or even more diameter; tan to white…...
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TL;DR: Five distinct sex-change mechanisms are identified among sequentially hermaphroditic fishes based on socio-ecological characteristics and neurophysiological models suggest that induction mechanisms, which require at least two categories of environmental stimuli, may have evolved from the simpler suppression mechanisms, who require only one kind of input from the environment.
Abstract: Five distinct sex-change mechanisms are identified among sequentially hermaphroditic fishes based on socio-ecological characteristics. The primary determinants of the sex-change mechanisms appear to be social organization and mating system, which in turn depend on resource distribution in space and time. The ability of a single individual to control all mating in the social unit, which is related to the size of the social unit, differentiates three suppression mechanisms from two induction mechanisms. Sex-change suppression, which is characteristic of species with small group size and rigid dominance hierarchies, refers to inevitable sex change in the absence of group dominance. Ability to migrate between resource patches differentiates protogynous suppression (e.g. inLabroides dimidiatus) from protandrous suppression (e.g. inAmphiprion spp.). Early sex change appears to have evolved from protogynous suppression under special conditions involving the loss of mating control by a single dominant individual in certain species (e.g.Centropyge spp. ). Sex-change induction, which is characteristic of species with large social groups lacking rigid dominance hierarchies, refers to the requirement that sex change must be induced by specific characteristics of (or changes in) the social group, regardless of dominance status. Ability to distinguish sex, or its importance, differentiates sex-ratio induction (e.g.Anthias squamipinnis) from size-ratio induction (e.g.Thalassoma spp.). Alternative models account for the possibility that all cases of sex change require stimulation from smaller conspecifics (universal induction-inhibition model) or that all fish have the genetic capacity to switch mechanisms, depending on changing ecological conditions and resulting changes in mating system (behavioral-scaling model). Neurophysiological models suggest that induction mechanisms, which require at least two categories of environmental stimuli, may have evolved from the simpler suppression mechanisms, which require only one kind of input from the environment.
155 citations
TL;DR: The trophic niches of 13 sympatric species of damselfishes are determined by combining stable isotope (δ15N and δ13C) and stomach content analyses, revealing that their choice of habitat on the reef and their behavior appear to be good predictors of diet in this group.
Abstract: The damselfishes, with more than 340 species, constitute one of the most important families that live in the coral reef environment. Most of our knowledge of reef-fish ecology is based on this family, but their trophic ecology is poorly understood. The aim of the present study was to determine the trophic niches of 13 sympatric species of damselfishes by combining stable isotope (δ15N and δ13C) and stomach content analyses. Isotopic signatures reveal three main groups according to their foraging strategies: pelagic feeders (Abudefduf sexfasciatus, A. sparoides, A. vaigiensis, Chromis ternatensis, C. dimidiata, Dascyllus trimaculatus and Pomacentrus caeruleus), benthic feeders (Chrysiptera unimaculata, Plectroglyphidodon lacrymatus and Amphiprion akallopisos) and an intermediate group (D. aruanus, P. baenschi and P. trilineatus). Stomach contents reveal that planktonic copepods and filamentous algae mainly represent the diets of pelagic feeders and benthic feeders, respectively. The intermediate position of the third group resulted from a partitioning of small planktonic prey, small vagile invertebrates and filamentous algae. In this last feeding group, the presence of a wide range of δ13C values in P. trilineatus suggests a larger trophic niche width, related to diet-switching over time. Some general considerations about the feeding habits of damselfishes reveal that their choice of habitat on the reef and their behavior appear to be good predictors of diet in this group. Benthic (algae and/or small invertebrates) feeders appear to be solitary and defend a small territory on the bottom; zooplankton feeders remain in groups just above the reef, in the water column.
102 citations
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TL;DR: Techniques employing 14C have been most valuable for investigating this movement of fixed carbon from autotroph to heterotroph in most symbiotic associations.
Abstract: Summary
1. The bulk of the fixed carbon which moves from autotroph to heterotroph in most symbiotic associations is in a single compound, a carbohydrate. Techniques employing 14C have been most valuable for investigating this movement.
2. Most ‘zoochlorellae’ belong to the Chlorococcales, and they release carbohydrate to the animal tissue as either glucose or maltose. In some molluscs, the ‘zoochlorellae’ are actually chloroplasts, possibly derived from siphonaceous algae. Although it is known that these chloroplasts supply photosynthetically fixed carbon to the animal tissue, the form of the carbon compounds which move is not known. In Convoluta roscoffensis the ‘zoochlorellae’ belong to the Pyramimonadales, but carbohydrate movement has not yet been directly studied in this association.
3. Most ‘zooxanthellae’ belong to the Dinophyceae. In associations involving co-elenterates and molluscs, glycerol is the main carbohydrate moving to the animal. Homogenates of the host animal tissue stimulate excretion by isolated zooxanthellae.
4. In lichens, symbiotic blue-green algae release glucose to the fungus, but the various genera of green algae that have been studied all release polyols (either ery-thritol, ribitol or sorbitol). Lichen fungi rapidly synthesize mannitol from all these compounds. When lichen algae are isolated into pure culture, they soon lose the ability to excrete carbohydrate, and intracellular production of the carbohydrate that is excreted either becomes much reduced, or ceases altogether.
5. Mostly indirect evidence indicates that sucrose is the main carbohydrate moving from flowering plants to their associated symbiotic fungi. Diversion of the translocation stream towards the site of the association occurs. The fungi convert host sugars to their own carbohydrates, principally trehalose and polyols.
6. ‘Saprophytic’ higher plants are all obligately mycotrophic and receive carbohydrate from their associated fungi. In at least some associations, the fungus is simultaneously associated with an autotrophic higher plant, which is the ultimate source of carbohydrate for the association.
7. Some parasitic higher plants possess chlorophyll, but the extent to which they depend on their host for carbohydrate varies with different species. Green mistletoes evidently derive negligible carbon from their hosts, but other green parasites derive at least some. There is no evidence that any of the chlorophyll-containing parasites export carbohydrate back to their hosts. Parasitic higher plants which lack chlorophyll presumably derive all their carbohydrates from their hosts, but experimental investigations of this are scarce.
8. Comparison between different types of symbiotic association show that a number of common features emerge.
9. The algal symbionts of both invertebrates and lichens have, in comparison to free-living forms, reduced growth rates and greater incorporation of fixed carbon into soluble carbohydrates. They excrete a much greater proportion of their fixed carbon than free-living forms, and most of it is usually as a single carbohydrate. Particularly striking is the fact that the excreted carbohydrate is one which is either not the major intracellular carbohydrate, or one which ceases or nearly ceases to be produced in culture.
10. The translocation stream of autotrophic higher plants is diverted towards the site of association with either fungi or parasitic higher plants, but it is not known how this is achieved.
11. In all associations, the cell walls of the autotroph become reduced or modified at the site of contact with the heterotroph, but it seems likely that this is not directly connected with the mechanism of carbohydrate transfer between the symbionts.
12. In many associations, the heterotroph rapidly converts host sugars into other compounds (frequently into its own carbohydrates which are usually different from those of the host). This may serve to maintain a concentration gradient and so ensure a continued flow from the host.
13. Polyols feature prominently in symbiotic and parasitic associations, not only as the carbohydrates of many plant heterotrophs, but also as the form of carbohydrate released by both zooxanthellae and the green algae of lichens to their heterotrophic partners.
344 citations
Book•
01 Jan 1971
TL;DR: Parasitology: The biology of animal parasites, Paras itology: the biology ofAnimal parasites, کتابخانه مرکزی دانشگاه علوم پزشدکی اتهران.
Abstract: Parasitology: the biology of animal parasites , Parasitology: the biology of animal parasites , کتابخانه مرکزی دانشگاه علوم پزشکی تهران
233 citations