Symbiotic Shrimp Research Articles

Exploring the mimetic pigmentation of symbiotic shrimps associated with echinoderms

Exploring the mimetic pigmentation of symbiotic shrimps associated with echinoderms

Exploring symbiont gene expression in two echinoid-associated shrimp species under host separation

Symbiotic relationships are omnipresent and particularly diverse in the marine world. In the Western Indian Ocean, the sea urchin Echinometra mathaei associates with two obligate ectosymbiotic shrimp species, Tuleariocaris holthuisi and Arete indicus. These shrimps are known for their host-dependent nature. T. holthuisi, for example, exhibits severe host separation syndrome, showing signs of stress and rapid mortality when isolated. Specific host pigments called spinochromes seem essential for T. holthuisi survival. Our study employs a transcriptomic approach to assess the stress induced by host separation on these shrimps.Using paired-end Illumina HiSeq technology, we analyzed transcriptomes of both species under three conditions: (i) symbionts on their host (CC), (ii) isolated symbionts in seawater (IC), and (iii) isolated symbionts in spinochrome-enriched seawater (IC + S).Sequencing revealed a total of 217,832 assembled unigenes, with an N50 value of 2061 bp. Isolated T. holthuisi showed 16.5 % DEGs (IC/CC), reduced to 8.5 % with spinochromes (IC + S/CC), both compared to the control condition (CC). Further analyses of stress-related genes show that T. holthuisi expressed stress-related genes when isolated in comparison to the control (IC/CC). Notably, heat shock proteins (HSPs) were significantly up-regulated in isolated T. holthuisi, especially without spinochromes. In contrast, A. indicus displayed differential expression of diverse genes, suggesting an adaptive micro-regulation mechanism to cope with isolation stress.This study pioneers the use of NGS in exploring the transcriptomic responses of symbiotic shrimp species, shedding some light on the molecular impact of the host-separation syndrome and chemical dependencies.

Notes on the morphology, distribution and bionomics of Phyllodiscus semoni (Anthozoa: Actiniaria: Aliciidae)

Phyllodiscus semoni Kwietniewski, 1897, a little-known species of sea anemones of the family Aliciidae, is quite widely distributed in the tropics but has not been recorded from the Spratly Islands so far. The reason that the range of this species is poorly studied lies not only in the fact that many tropical areas are still poorly explored but also in the peculiar appearance of this animal in the sea. It rarely extends its tentacles during daylight hours and is not readily recognised by divers and researchers as an actinian. Our underwater observations, accompanied by high-resolution photography and specimen collection, evidence the presence of this species along the continental coast of Vietnam and in the waters of the Spratly Archipelago. During the dives, some observations were made on the behavior of the polyps and symbiotic shrimp living on their bodies. This species of sea anemones can cause severe skin burns in humans, which is confirmed by our experience. Summarised literature data on the distribution of Ph. semoni is provided.

Mating system of the symbiotic shrimp Chernocaris placunae (Decapoda: Palaemonidae) in Vietnam: social monogamy and differences between two sites with contrasting environmental conditions

Mating system of the symbiotic shrimp Chernocaris placunae (Decapoda: Palaemonidae) in Vietnam: social monogamy and differences between two sites with contrasting environmental conditions

Species-specific metabolites mediate host selection and larval recruitment of the symbiotic seastar shrimp

In marine environments, host selection, defining how symbiotic organisms recognize and interact with their hosts, is often mediated by olfactory communication. Although adult symbionts may select their hosts detecting chemosensory cues, no information is available concerning the recruitment of symbiotic larvae which is a crucial step to sustain symbioses over generations. This study investigates the olfactory recognition of seastar hosts by adult Zenopontoniasoror shrimps and the recruitment of their larvae. We examine the semiochemicals that influence host selection using chemical extractions, behavioural experiments in olfactometers, and mass spectrometry analyses. After describing the symbiotic population and the embryonic development of shrimps, our results demonstrate that asterosaponins, which are traditionally considered as chemical defences in seastars, are species-specific and play a role in attracting the symbiotic shrimps. Adult shrimps were found to be attracted only by their original host species Culcitanovaeguineae, while larvae were attracted by different species of seastars. This study provides the first chemical identification of an olfactory cue used by larvae of symbiotic organisms to locate their host for recruitment. These findings highlight the importance of chemical communication in the mediation of symbiotic associations, which has broader significant implications for understanding the ecological dynamics of marine ecosystems.

New host for a homeless shrimp: Records of native symbiotic shrimps living on a non-indigenous octocora

New host for a homeless shrimp: Records of native symbiotic shrimps living on a non-indigenous octocora

Physiological responses of the symbiotic shrimp Ancylocaris brevicarpalis and its host sea anemone Stichodactyla haddoni to ocean acidification

In this study, the physiology of symbiotic ‘peacock-tail’ shrimp Ancylocaris brevicarpalis and its host ‘Haddon's carpet’ sea anemone Stichodactyla haddoni were tested under lowered pH (7.7) and control (8.1) conditions. The biochemical responses such as digestive enzyme (AP), organic acids (lactate and succinate), oxidative damages (MDA), antioxidants metabolites/enzymes (ASC, GSH, SOD, CAT, APX, GPX, GR, POX, and PHOX), and detoxification enzyme (GST) were measured. The AP showed insignificantly reduced values in both the organisms in lowered pH conditions compared to control indicating the effect of abiotic stress. The hierarchical clustering analysis indicated low MDA in sea anemone can be explained by higher POX, APX, GR, ASC, and GSH levels compared to shrimps. However, the detoxification enzyme GST showed less activity in sea anemones compared to shrimps. The results suggest that A. brevicarpalis and sea anemone S. haddoni may have deleterious effects when exposed to short-term acidification stress.

First Atlantic record of the rare infaunal shrimp Salmoneus erasimorum Dworschak, Abed-Navandi amp; Anker, 2000 (Malacostraca: Decapoda: Alpheidae).

The rare symbiotic alpheid shrimp Salmoneus erasimorum Dworschak, Abed-Navandi Anker, 2000 was previously known from a single specimen collected with a suction pump on the Croatian coast in the Adriatic Sea, together with its host, the ghost shrimp, Gilvossius tyrrhenus (Petagna, 1792). A second record of S. erasimorum is presented here, with a diagnosis and the first colour photographs, based on a single specimen collected in northern Brittany, France, also with a suction pump, but without its host. This is also the first record of the species on the European coast of the Atlantic Ocean. An annotated list and a key to the species of Salmoneus currently known from the eastern Atlantic and the Mediterranean Sea are provided.

Mating System of the Snapping Shrimp Synalpheus brevicarpus (Caridea, Alpheidae) Inhabiting Sponges Dysidea sp. (Demospongiae).

AbstractThe lifestyle of symbiotic species in the genus Synalpheus can vary from pair living to eusocial. A pair-living social system commonly implies the adoption of a monogamous mating system. In this study, we used the symbiotic shrimp Synalpheus brevicarpus in association with the sponge Dysidea sp. to test the hypothesis that heterosexual pairs of symbiotic shrimps can adopt a monogamous mating system when living in association with a morphologically complex host. We collected a total of 40 sponges, which were inhabited by 76 shrimps: 41 males, 33 females, and 2 juveniles. Synalpheus brevicarpus is sexually dimorphic, with males displaying proportionately larger weaponry (snapping claws) and a smaller average body size than females. Sponges were more often inhabited by a pair of heterosexual shrimps than expected by chance. Larger sponges were inhabited by more than one pair of shrimps in which the sex ratio did not differ significantly from 1∶1. Pairs of heterosexual shrimps were recorded, with females carrying embryos in all stages of embryonic development. Our results indicate that S. brevicarpus is a pair-living shrimp with a monogamous social and mating system that may also guard spaces or areas within its sponge host. Our hypothesis of monogamy is supported by the observations on pair living, sex ratio, and sexual dimorphism in body size and weaponry in this species.

First record of the symbiotic palaemonid shrimp Hamodactylus boschmai Holthuis, 1952 (Decapoda, Caridea) from Korea

Abstract Here, the symbiotic palaemonid shrimp Hamodactylus boschmai is recorded from Korean waters for the first time, based on specimens collected from different invertebrate hosts by trimix diving at depths of between 45 and 60 m in Jejudo Island. This species can readily be distinguished from its congeners by the presence of a distinct supraorbital tooth, the proximal segment of the antennular peduncle having a single tooth on the distolateral margin, the presence of a denticulate lamina along the entire cutting edge of the fingers of the first pereiopod chela, and the chela of the second pereiopods having a strongly hooked tip on the movable finger. An illustrated description, colour photographs, and a comparison of partial mitochondrial cytochrome c oxidase subunit I gene sequences are provided.

Antimicrobial Peptides and Ectosymbiotic Relationships: Involvement of a Novel Type IIa Crustin in the Life Cycle of a Deep-Sea Vent Shrimp.

The symbiotic shrimp Rimicaris exoculata dominates the macrofauna inhabiting the active smokers of the deep-sea mid Atlantic ridge vent fields. We investigated the nature of the host mechanisms controlling the vital and highly specialized ectosymbiotic community confined into its cephalothoracic cavity. R. exoculata belongs to the Pleocyemata, crustacean brooding eggs, usually producing Type I crustins. Unexpectedly, a novel anti-Gram-positive type II crustin was molecularly identified in R. exoculata. Re-crustin is mainly produced by the appendages and the inner surfaces of the cephalothoracic cavity, embedding target epibionts. Symbiosis acquisition and regulating mechanisms are still poorly understood. Yet, symbiotic communities were identified at different steps of the life cycle such as brooding stage, juvenile recruitment and molt cycle, all of which may be crucial for symbiotic acquisition and control. Here, we show a spatio-temporal correlation between the production of Re-crustin and the main ectosymbiosis-related life-cycle events. Overall, our results highlight (i) a novel and unusual AMP sequence from an extremophile organism and (ii) the potential role of AMPs in the establishment of vital ectosymbiosis along the life cycle of deep-sea invertebrates.

Baseline diversity and host relationships of symbiotic caridean shrimps on the coast of northern Taiwan, southern East China Sea, prior to the establishment of a conservation area

Symbiotic caridean shrimps were collected from diverse host invertebrates in a coral reef habitat of the southern East China Sea during the summer from April to August in 2014. Regular weekly sampling was conducted by scuba diving in the zone above 25 m depth at the Wang-Hai-Xiang Bay (also called as Fan-Zai-Aou Bay) in northeastern Taiwan. This region is influenced by the China Coast Current and the Kuroshio Current. In total, 27 species of shrimp in 20 genera and 3 families were identified, being taxonomically dominated by Palaemonidae (70.4% of species) and followed by Alpheidae (22.2%) and Hippolytidae (7.4%). The shrimp species were apportioned among hosts of various groups, as follows: scleractinians (45.2%), gorgonians (16.1%), echinoids (12.9%), crinoids (9.7%), actiniarians (6.5%), alcyonarians (3.2%), hydroids (3.2%), and sponges (3.2%). Six species are reported for the first time from the waters of Taiwan: Synalpheus neomeris (de Man, 1897); Cristimenes zanzibaricus (Bruce, 1967); Manipontonia paeneglabra Bruce, 2012; Miopontonia yongei Bruce, 1985; Palaemonella spinulata Yokoya, 1936; and Thaumastocaris streptopus Kemp, 1922. Of these, C. zanzibaricus also represents a northern range extension for the species. Five species, Arete indicus Coutiere, 1903; Cuapetes amymone (de Man, 1902); Jocaste lucina (Nobili, 1901); Palaemonella pottsi (Borradaile, 1915); and Pontoniopsis comanthi Borradaile, 1915, showed higher than 60% prevalence on their hosts. These results provide useful baseline information on symbiotic shrimps prior to the establishment of a conservation area at this site in 2016, and also fill in faunal distribution gaps in the coral reef region between the southern Ryukyu arc and the Coral Triangle.

Shrimps of the genus Periclimenes (Crustacea, Decapoda, Palaemonidae) associated with mushroom corals (Scleractinia, Fungiidae): linking DNA barcodes to morphology

Most marine palaemonid shrimp species live in symbiosis with invertebrates of various phyla. These associations range from weak epibiosis to obligatory endosymbiosis and from restricted commensalism to semi-parasitism. On coral reefs, such symbiotic shrimps can contribute to the associated biodiversity of reef corals. Among the host taxa, mushroom corals (Cnidaria: Anthozoa: Fungiidae) are known to harbour various groups of symbionts, including shrimps. Some but not all of these associated species are host-specific. Because data on the host specificity of shrimps on mushroom corals are scarce, shrimp species of the genus Periclimenes were collected from mushroom corals during fieldwork in Lembeh Strait, North Sulawesi, Indonesia. Using molecular (COI barcoding gene) and morphological methods, three species of Periclimenes were identified: P. diversipes, P. watamuae and a species new to science, P. subcorallum sp. nov., described herein. Their host specificity was variable, with eight, three and two fungiid host records, respectively. It is concluded that shrimp species of the genus Periclimenes show much overlap in their host choice and that particular morphological traits in the host species appear to play a more important role than phylogenetic affinities within the host group.

Reproductive strategies of the crinoid-associated shrimps <i>Cristimenes commensalis</i> (Borradaile, 1915) and <i>Pontoniopsis comanthi</i> Borradaile, 1915 (Crustacea: Palaemonidae)

Tropical shallow-water crinoids offer shelter to a diversity of marine life, including various symbiotic palaemonid shrimp species. In this study, the reproductive features of the shrimps Cristimenes commensalis and Pontoniopsis comanthi inhabiting comatulid crinoids are studied and compared. Ovigerous females were collected from the crinoids Anneissia bennetti and Comaster nobilis from Iriomote-jima, Japan. All specimens were examined for the following traits: carapace length, fecundity, embryo volume, brood mass volume and dry weight of the females and the eggs. Cristimenes commensalis produced 15–117 eggs with a volume of 0.04 mm3 ±0.00, whereas the smaller-sized species P. comanthi produced 12–57 eggs with a volume of 0.02 mm3 ±0.01. The reproductive output (RO) of C. commensalis was 0.16±0.03, considerably lower than that of P. comanthi at 0.31±0.05. Data is beginning to emerge on the fecundity and reproductive output of symbiotic palaemonid shrimps, although comparisons remain hampered by the general lack of knowledge on their biology in general. Pontoniopsis comanthi has the highest recorded reproductive output so far, despite being the smallest species studied. Our results confirm that inhabiting a sheltered habitat allows symbiotic shrimps to allocate more energy to embryo production than free-living species. Different reproductive strategies are, however, apparent for these species inhabiting the same host species, implying the existence of differential selective forces.

Identification of a new stony coral host for the anemone shrimp Periclimenes rathbunae Schmitt, 1924 with notes on the host-use pattern

Periclimenes rathbunae Schmitt, 1924 is a western Atlantic symbiotic shrimp species mainly associating with anemones. Adult shrimps of P . rathbunae are characterised by an orange-white spotted colour pattern. During fieldwork along the coast of Curaçao (2013), morphologically similar, though generally smaller sized shrimps were collected from the stony coral Dendrogyra cylindrus Ehrenberg, 1834. These specimens were overall more translucent. This study elucidates the taxonomic status of the coral-associated specimens in relation to anemone-associated specimens of P. rathbunae and related anemone-associated species using one nuclear (histone H3, H3), a mitochondrial protein-coding (cytochrome oxidase subunit I, COI) and a mitochondrial ribosomal RNA (16S) gene. Molecular phylogenetic reconstructions clustered the coral-associated specimens with anemone-associated P. rathbunae within a distinct clade, revealing that the aberrant coral-associated shrimp specimens belong to P. rathbunae. It can be concluded that 1) the stony coral D. cylindrus is a host of P. rathbunae, constituting the first record of an association between a scleractinian coral and a palaemonid shrimp species in the Atlantic Ocean; 2) the colour pattern of P. rathbunae is a phenotypically plastic characteristic that varies with size and is depending on the host species; and 3) mean body size of P. rathbunae is smaller on D. cylindrus than on the anemone Stichodactyla helianthus. This raises interesting questions about patterns of host use for this species and warrants further in-depth field ecological study for this species.

The 'scorpion shrimp', a new species of the genus Metapontonia (Crustacea: Decapoda: Palaemonidae) from Taiwan, with new generic record from Papua New Guinea.

A new species of shrimp Metapontonia scorpio symbiotic with scleractinian coral Diploastrea heliopora is described from Taiwan. The species belongs to the smallest symbiotic shrimps of the family Palaemonidae. It is remarkable by a unique ability to turn its last two pleonites with tail fan dorsally over the 4^th and preceding pleonal segments, thus resembling scorpions. For such movement, the respective opposing dorsal margins of the 4^th-6^th segments are deeply concave. The new species is characterized by a short dorsally directed rostrum, incomplete orbit, semicircular scaphocerite, and medially concave basal antennular segment. The only species of the genus, M. fungiacola, is compared with the new species based on morphology and DNA. Metapontonia fungiacola is for the first time reported from Taiwan and Papua New Guinea. The morphological and colour variability of the species is discussed. The scleractinian corals Platygyra lamellina (Merulinidae), Lobophyllia hemprichii, cf. Micromusa sp., Symphyllia cf. radians (Lobophylliidae), and Galaxea sp. (Oculinidae), are new host records for the species.

Symbiotic partner specificity and dependency of two gobies (Apocryptodon punctatus and Acentrogobius sp. A) and four alpheid shrimps inhabiting the temperate estuary of southern Japan

We collected two gobies, Apocryptodon punctatus and Acentrogobius sp. A, and four alpheid shrimps from an estuary in southern Japan, to identify the symbiotic shrimps with gobies and to understand their partner specificity and dependency. Analysis based on generalized linear models identified two specific partners for each goby. A. punctatus frequently coexisted with partners and showed similar habitats, suggesting that this goby might be an obligate mutualist. Acentrogobius sp. A had lower rates of coexistence and appeared in habitats different from one of its partners, suggesting that this goby might be a facultative mutualist.

Population distribution, host-switching, and chemical sensing in the symbiotic shrimp Lysmata pederseni: implications for its mating system in a changing reef seascape

Lysmata pederseni, a protandric simultaneously hermaphroditic shrimp that inhabits the tube sponge Callyspongia vaginalis, is monogamous in the central and southeastern Caribbean Sea. We tested the null hypothesis of monogamy in a northern Caribbean population. In the Florida Keys, shrimps did not inhabit host individuals in pairs with a frequency greater than expected by chance alone. Hermaphrodites inhabited sponges solitarily and often brooded embryos. Hermaphrodites do not store sperm and need to be inseminated shortly after molting to fertilize a new batch of eggs. Thus, males and/or other hermaphrodites are likely switching among host individuals in search of sexual partners. Field experiments demonstrated low shrimp host fidelity. Host residence time was ~2 times shorter for males than for hermaphrodites. We inferred a polygynandrous mating system in L. pederseni from the Florida Keys, with male-role and young hermaphrodites often moving among sponges in search of older, more sedentary, female-role hermaphrodites. We expected shrimps to use water-borne chemical cues originating from conspecifics or sponges to locate sexual partners. Experiments demonstrated that shrimps were attracted to water-borne cues originating from sponges but not conspecifics. We have described the mating system of a reef-associated shrimp in a fast-pace shifting seascape increasingly dominated by sponges and vanishing stony corals. In the central and southeastern Caribbean Sea, with greater coral cover and lower sponge abundance than in the Florida Keys, the same species is monogamous. Whether or not similar shifts in the social organization of other coral reef-dwelling marine organisms are occurring due to contemporary changes in seascapes is a relevant topic that deserves further attention.

Insights into the morphology of symbiotic shrimp eyes (Crustacea, Decapoda, Palaemonidae); the effects of habitat demands.

Morphometric differences in the optical morphology of symbiotic palaemonid shrimps can be observed among species symbiotic with different host organisms. Discriminant functional analysis revealed three distinct groups within the species examined. Of these, bivalve symbionts appear to have an eye design that is solely unique to this host-symbiont grouping, a design that spans across multiple genera of phylogenetically unrelated animals. Although some taxonomic effects may be evident, this does not explain the difference and similarities in eye morphology that are seen within these shrimps. Therefore evolutionary pressures from their host environments are having an impact on the optical morphology of their eyes however, as indicated by host-hopping events there ecological adaptations occur post host invasion.

NOTES ON SYMBIOTIC DECAPOD CRUSTACEANS FROM GORGONA ISLAND, COLOMBIA, WITH A REVISION OF THE EASTERN PACIFIC SPECIES OF TRAPEZIA (BRACHYURA, XANTHIDAE), SYMBIONTS OF SCLERACTINIAN CORALS

Collections of decapod crustaceans associated with scleractinian corals at Gorgona Island, Colombia, have provided material for a revision of the eastern Pacific specics of Trapezia (Brachyura, Xanthidae), obligate symbionts of the coral Pocillopora. Four sympatric specie are recognized: T. corallina Gerstaecker, T. formosa Smith, T. ferruginea Latreille, and T. digitalis Latreille. Two species of symbiotic natantian shrimps [Harpiliopsis spinigera (OrtmannJ from Pocillopora and Periclhnenes soror Nobili from asteroids] are recorded from Gorgona for the first time.