Symbiotic Marine Research Articles

Microbial Metabolomics' Latest SICRIT: Soft Ionization by Chemical Reaction In-Transfer Mass Spectrometry.

Microbial metabolomics studies are a common approach for identifying microbial strains that have a capacity to produce new chemistries both in vitro and in situ. A limitation to applying microbial metabolomics to the discovery of new chemical entities is the rediscovery of known compounds, or "known unknowns." One factor contributing to this rediscovery is that the majority of laboratories use one ionization source─electrospray ionization (ESI)─to conduct metabolomics studies. Although ESI is an efficient, widely adopted ionization method, its widespread use may contribute to the reidentification of known metabolites. Here, we present the use of a dielectric barrier discharge ionization (DBDI) for microbial metabolomics applications through the use of soft ionization chemical reaction in-transfer (SICRIT). Additionally, we compared SICRIT to ESI using two different Vibrio species: Vibrio fischeri, a symbiotic marine bacterium, and Vibrio cholerae, a pathogenic bacterium. Overall, we found that the SICRIT source ionizes a different set of metabolites than ESI, and it has the ability to ionize lipids more efficiently than ESI in the positive mode. This work highlights the value of using more than one ionization source for the detection of metabolites.

Microbial metabolomics' latest SICRIT: Soft ionization by Chemical Reaction in-Transfer mass spectrometry.

Microbial metabolomics studies are a common approach to identifying microbial strains that have a capacity to produce new chemistries both in vitro and in situ. A limitation to applying microbial metabolomics to the discovery of new chemical entities is the rediscovery of known compounds, or "known unknowns." One contributing factor to this rediscovery is the majority of laboratories use one ionization source-electrospray ionization (ESI)-to conduct metabolomics studies. Although ESI is an efficient, widely adopted ionization method, its widespread use may contribute to the re-identification of known metabolites. Here, we present the use of a dielectric barrier discharge ionization (DBDI) for microbial metabolomics applications through the use of soft ionization chemical reaction in-transfer (SICRIT). Additionally, we compared SICRIT to ESI using two different Vibrio species-Vibrio fischeri, a symbiotic marine bacterium, and Vibrio cholerae, a pathogenic bacterium. Overall, we found that the SICRIT source ionizes a different set of metabolites than ESI, and it has the ability to ionize lipids more efficiently than ESI in positive mode. This work highlights the value of using more than one ionization source for the detection of metabolites.

A novel three-part pharynx and its parallel evolution within symbiotic marine nematodes (Desmodoroidea, Stilbonematinae)

Stilbonematinae are nematodes commonly found in shallow marine sands. They are overgrown by a genus- and species-specific coat of chemoautotrophic sulphur-oxidizing ectosymbiotic bacteria which profit from the vertical migration of their hosts through the chemocline by alternately gaining access to oxidizing and reducing chemical species, while in return, the host feeds on its symbionts. The subfamily exhibits a large morphological variability; e.g. the anterior pharynx is cylindrical in genera possessing a voluminous coat, but species with a bacterial monolayer possess a distinctly swollen corpus and therefore a tripartite pharynx. Since 18S-based phylogenetic analyses do not show close relationships between corpus-bearing species, we investigated the pharynx morphology using phalloidin staining in combination with confocal laser scanning microscopy, transmission electron microscopy and light microscopy in order to assess an independent evolution. The class-wide stable position of the subventral pharynx ampullae was used as a morphological marker. Ampullae are positioned at the anterior-most end of the isthmus in Cyathorobbea, further posterior in Catanema and Robbea and inside the corpus in Laxus oneistus. We therefore conclude an independent evolution of corpus enlargements within Stilbonematinae. This further suggests that pharynx morphology is driven by the volume of the symbiotic bacterial coat rather than phylogeny. Based on an existing mathematical model, an enlarged corpus should enable its bearer to ingest food in smaller quantities, in gourmet style, whereas a cylindrical pharynx would restrict its bearer to ancestral gourmand feeding. A review of pharynx types of Nematoda showed that the Stilbonematinae pharynx is substantially different compared to other tripartite pharynges. The lack of pharyngeal tubes and valves, the undivided corpus and evenly distributed nuclei in the isthmus warrant the definition of the “stilbonematoid” three-part pharynx.

A review of Palaemonella (Decapoda: Caridea: Palaemonidae), with clarification of the taxonomic status of Cuapetes americanus, Eupontonia and Vir.

The pantropical genus Palaemonella Dana, 1852 (Caridea: Palaemonidae) currently includes 27 species of free-living and symbiotic marine shrimps. The monophyly of Palaemonella with respect to several closely related genera, however, has been questioned by recent analyses. We tested the monophyly of Palaemonella based on multigene phylogenetic analysis and the genus was revealed to be a paraphyletic assemblage by inclusion of species of the genera Eupontonia Bruce, 1971 and Vir Holthuis, 1952, and two genetic lineages of the western Atlantic Cuapetes americanus (Kingsley, 1878). We recognise one of the latter lineages as the previously described Periclimenes rhizophorae Lebour, 1949. Eupontonia and Vir are synonymised with Palaemonella . We also transfer Cuapetes americanus and Periclimenes rhizophorae to Palaemonella . Species previously assigned to Vir were revised; V. colemani Bruce, 2003, V. orientalis (Dana, 1852), V. philippinensis Bruce & Svoboda, 1984 and V. smiti Fransen & Holthuis, 2007 are regarded as valid species of Palaemonella ; Vir longidactylus Marin, 2008 is synonymised with P. smiti ; and the status of V. euphyllius Marin & Anker, 2005 remains unresolved. Palaemonella is currently regarded as a taxon with variable states of two main diagnostic characters, i.e. the plesiomorphic mandibular palp (fully reduced in P. americana ) and the hepatic tooth (fully reduced in former species of Vir and Eupontonia - evidently due to symbiotic modes of life). ZooBank: urn:lsid:zoobank.org:pub:7EEBC655-7EDE-4E46-BCB2-2A3BA16ED7DD.

Spatial metabolomics for symbiotic marine invertebrates

Spatial metabolomics for symbiotic marine invertebrates

Spatial metabolomics for symbiotic marine invertebrates.

Microbial symbionts frequently localize within specific body structures or cell types of their multicellular hosts. This spatiotemporal niche is critical to host health, nutrient exchange, and fitness. Measuring host-microbe metabolite exchange has conventionally relied on tissue homogenates, eliminating dimensionality and dampening analytical sensitivity. We have developed a mass spectrometry imaging workflow for a soft- and hard-bodied cnidarian animal capable of revealing the host and symbiont metabolome in situ, without the need for a priori isotopic labelling or skeleton decalcification. The mass spectrometry imaging method provides critical functional insights that cannot be gleaned from bulk tissue analyses or other presently available spatial methods. We show that cnidarian hosts may regulate microalgal symbiont acquisition and rejection through specific ceramides distributed throughout the tissue lining the gastrovascular cavity. The distribution pattern of betaine lipids showed that once resident, symbionts primarily reside in light-exposed tentacles to generate photosynthate. Spatial patterns of these metabolites also revealed that symbiont identity can drive host metabolism.

Isolation and Characterization of Anticancer Compound Producing Marine Paenibacillus lentimorbus SAGM 3 Collected from a Sea Anemone, Heteractis species

Sea anemone-associated bacteria were considered promising candidates for the synthesis of many novel bioactive compounds. Thus culturable symbiotic bacteria that exist in the sea anemones met much attention when compared to other benthic marine dwellers. In this study, an attempt was made to explore the anticancer potentials of symbiotic bacteria isolated from a sea anemone, Heteractis species. Nine symbiotic bacteria were isolated, pure cultured and screened for their anticancer potential using two breast cancer cell lines. Among the strains, SAGM 3 showed appreciable growth inhibition activity of 43.1% and 47.1% against the studied cell lines, viz. MCF7 and MDA-MB-231 and this strain was selected for further studies. Based on the 16S rRNA molecular profiling, the SAGM 3 isolate was noted as Paenibacillus lentimorbus and the sequence of SAGM 3 was deposited in GeneBank with the accession number MW737456.1. During the growth kinetics profiling, maximum bacterial growth rate and anticancer activities were recorded from 60 to 96 hrs of incubation. The present investigation provides baseline data understanding the pharmaceutical significance of a symbiotic marine bacterium procured from the sea anemone, Heteractis species.

Molecular phylogeny and historical biogeography of marine palaemonid shrimps (Palaemonidae: Palaemonella–Cuapetes group)

Palaemonidae is the most speciose shrimp family within the infraorder Caridea, composed predominately of freshwater species and marine symbiotic species. The subject of this study is a clade of mainly free-living marine taxa representing a basally separated lineage from most of the symbiotic marine palaemonid genera. Phylogenetic and biogeographic relationships were explored by analysing sequence data from two mitochondrial and four nuclear markers. Maximum likelihood and Bayesian analyses, based on sequences from 52 species of 11 genera, provided similar tree topologies revealing the genera Palaemonella, Cuapetes and Eupontonia as non-monophyletic groups. Divergence time and S-DIVA analyses reveals that the focal clade originated during the Late Cretaceous in the Paleotethys region respective to the present Indo-West Pacific area, a minor part of which spread out to the eastern Pacific during the Paleocene, followed by further migration into the Atlantic (before the closure of the Panama Isthmus). The ancestral state reconstruction of host associations revealed eight independent symbiotic lineages originating from free-living ancestors, entering primary symbioses. The first associations with Cnidaria are estimated to have evolved in the Eocene. This study points to the need of taxonomic revisions of the non-monophyletic genera concerned.

Voratins A-C: Pyridinium Alkaloids from the Marine Dinoflagellate Effrenium voratum with Inhibitory Effects on Biomarkers for Benign Prostatic Hyperplasia.

Three voratin compounds (1-3) were isolated from the symbiotic marine dinoflagellate Effrenium voratum. The planar structures of 1-3 were determined by 1D and 2D NMR spectroscopy and HRESIMS, and the relative and absolute configurations were established using ROESY correlations, Mosher's method, and quantum calculations. All of the compounds are zwitterionic and contain a dihydroindolizinium ring and a spiroketal moiety. Compounds 1-3 were found to exhibit therapeutic effects against benign prostatic hyperplasia (BPH), as evaluated using testosterone propionate-treated LNCap and RWPE-1 human prostate cells. This excellent activity suggests that 1-3 are promising for the development of BPH treatments.

Characterization and genomic analysis of the first Oceanospirillum phage, vB_OliS_GJ44, representing a novel siphoviral cluster

BackgroundMarine bacteriophages play key roles in the community structure of microorganisms, biogeochemical cycles, and the mediation of genetic diversity through horizontal gene transfer. Recently, traditional isolation methods, complemented by high-throughput sequencing metagenomics technology, have greatly increased our understanding of the diversity of bacteriophages. Oceanospirillum, within the order Oceanospirillales, are important symbiotic marine bacteria associated with hydrocarbon degradation and algal blooms, especially in polar regions. However, until now there has been no isolate of an Oceanospirillum bacteriophage, and so details of their metagenome has remained unknown.ResultsHere, we reported the first Oceanospirillum phage, vB_OliS_GJ44, which was assembled into a 33,786 bp linear dsDNA genome, which includes abundant tail-related and recombinant proteins. The recombinant module was highly adapted to the host, according to the tetranucleotides correlations. Genomic and morphological analyses identified vB_OliS_GJ44 as a siphovirus, however, due to the distant evolutionary relationship with any other known siphovirus, it is proposed that this virus could be classified as the type phage of a new Oceanospirivirus genus within the Siphoviridae family. vB_OliS_GJ44 showed synteny with six uncultured phages, which supports its representation in uncultured environmental viral contigs from metagenomics. Homologs of several vB_OliS_GJ44 genes have mostly been found in marine metagenomes, suggesting the prevalence of this phage genus in the oceans.ConclusionsThese results describe the first Oceanospirillum phage, vB_OliS_GJ44, that represents a novel viral cluster and exhibits interesting genetic features related to phage–host interactions and evolution. Thus, we propose a new viral genus Oceanospirivirus within the Siphoviridae family to reconcile this cluster, with vB_OliS_GJ44 as a representative member.

The Internal Microenvironment of the Symbiotic Jellyfish Cassiopea sp. From the Red Sea

The characterization of the internal microenvironment of symbiotic marine invertebrates is essential for a better understanding of the symbiosis dynamics. Microalgal symbionts (of the family: Symbiodiniaceae) influence diel fluctuations of in host O2 and pH conditions through their metabolic activities (i.e., photosynthesis and respiration). These variations may play an important role in driving oxygen budgets and energy demands of the holobiont and its responses to climate change. In situ measurements using microsensors were used to resolve the O2 and pH diel fluctuations in the oral arms of non-calcifying cnidarian model species Cassiopea sp. (the “upside-down jellyfish”), which has an obligatory association with Symbiodiniaceae. Before sunrise, the internal O2 and pH levels were substantially lower than those in ambient seawater conditions (minimum average levels: 61.92 ± 5.06 1SE μmol O2 L–1 and 7.93 ± 0.02 1SE pH units, respectively), indicating that conditions within Cassiopea’s oral arms were acidified and hypoxic relative to the surrounding seawater. Measurements performed during the afternoon revealed hyperoxia (maximum average levels: 546.22 ± 16.45 1SE μmol O2 L–1) and internal pH similar to ambient levels (8.61 ± 0.02 1SE pH units). The calculated gross photosynthetic rates of Cassiopea sp. were 0.04 ± 0.013 1SE nmol cm–2 s–1 in individuals collected at night and 0.08 ± 0.02 1SE nmol cm–2 s–1 in individuals collected during the afternoon.

An Analysis of Biosynthesis Gene Clusters and Bioactivity of Marine Bacterial Symbionts.

Symbiotic marine bacteria have a pivotal role in drug discovery due to the synthesis of diverse biologically potential compounds. The marine bacterial phyla proteobacteria, actinobacteria and firmicutes are commonly associated with marine macro organisms and frequently reported as dominant bioactive compound producers. They can produce biologically active compounds that possess antimicrobial, antiviral, antitumor, antibiofilm and antifouling properties. Synthesis of these bioactive compounds is controlled by a set of genes of their genomes that is known as biosynthesis gene clusters (BGCs). The development in the field of biotechnology and bioinformatics has uncovered the potential BGCs of the bacterial genome and its functions. Now-a-days researchers have focused their attention on the identification of potential BGCs for the discovery of novel bioactive compounds using advanced technology. This review highlights the marine bacterial symbionts and their BGCs which are responsible for the synthesis of bioactive compounds.

Assessing the diversity of bacterial communities from marine sponges and their bioactive compounds

Symbiotic bacteria play vital roles in the survival and health of marine sponges. Sponges harbor rich, diverse and species-specific microbial communities. Symbiotic marine bacteria have increasingly been reported as promising source of bioactive compounds. A culturomics-based study was undertaken to study the diversity of bacteria from marine sponges and their antimicrobial potential. We have collected three sponge samples i.e. Acanthaster carteri, Rhytisma fulvum (soft coral) and Haliclona caerulea from north region (Obhur) of Red Sea, Jeddah Saudi Arabia. Total of 144 bacterial strains were isolated from three marine sponges using culture dependent method. Screening of isolated strains showed only 37 (26%) isolates as antagonists against oomycetes pathogens (P. ultimum and P. capsici). Among 37 antagonistic bacteria, only 19 bacterial strains exhibited antibacterial activity against human pathogens (Methicillin-resistant Staphylococcus aureus (MRSA) ATCC 43300, Pseudomonas aeruginosa ATCC 27853, Escherichia coli ATCC 8739, Enterococcus faecalis ATCC 29212). Four major classes of bacteria i.e γ-Proteobacteria, α-Proteobacteria, Firmicutes and Actinobacteria were recorded from three marine sponges where γ-Proteobacteria was dominant class. One potential bacterial strain Halomonas sp. EA423 was selected for identification of bioactive metabolites using GC and LC-MS analyses. Bioactive compounds Sulfamerazine, Metronidazole-OH and Ibuprofen are detected from culture extract of strain Halomonas sp. EA423. Overall, this study gives insight into composition and diversity of antagonistic bacterial community of marine sponges and coral from Red Sea and presence of active metabolites from potential strain. Our results showed that these diverse and potential bacterial communities further need to be studied to exploit their biotechnological significance.

Enhanced production of a bioactive molecule from a symbiotic marine bacterium, Paenibacillus macerans SAM 9 isolated from the sea anemone, Heteractis aurora

Enhanced production of a bioactive molecule from a symbiotic marine bacterium, Paenibacillus macerans SAM 9 isolated from the sea anemone, Heteractis aurora

Antibiofilm activity of symbiotic Bacillus species associated with marine gastropods

PurposeGenerally, symbiotic marine bacteria are renowned for the synthesis of compounds with bioactive properties, and this has been documented in many previous studies. Therefore, the present study was aimed to isolate novel bacterial symbionts of gastropods that have the ability to synthesize bioactive compounds. These bioactive compounds could be used effectively as antibiofilm agents in order to overcome the problems associated with biofilm.MethodsThe bacteria associated with the surface of marine gastropods were isolated and characterized. Following this, the bacterial metabolites were extracted and their antibiofilm effect was evaluated on biofilm-forming bacteria on artificial substrates. Moreover, the biofilm-forming bacterium Alteromonas sp. was treated with the extracts of symbiotic bacteria in order to evaluate the influence of extracts over the synthesis of extracellular polymeric substance (EPS). Besides, the biologically active chemical constituents of the extracts were separated using thin-layer chromatography and subjected to gas chromatography and mass spectrometry (GC-MS) analysis for characterization.ResultsThree bacterial strains belonging to the species Bacillus firmus, Bacillus cereus and Bacillus subtilis were identified from the bacterial community associated with the gastropods. The antibiofilm assays revealed that the extract of three symbiotic bacteria significantly (p < 0.05) reduced the biofilm formation by the marine bacterium Alteromonas sp. on artificial materials. Also, the EPS synthesis by Alteromonas sp. was significantly inhibited due to symbiotic bacterial extract treatment. The chemical composition of the bioactive fraction isolated from the symbiotic bacteria extract revealed that most of the detected compounds were belonging to aromatic acid, fatty acid and carboxylic acid.ConclusionThe results of this study clearly revealed that the bacteria belonging to the above listed Bacillus species can be considered as a promising source of natural antibiofilm agents.

Symbiodinolactone A, a new 12-membered macrolide from symbiotic marine dinoflagellate Symbiodinium sp.

A new 12-membered macrolide, symbiodinolactone A, was isolated from the culture broth of symbiotic marine dinoflagellate Symbiodinium sp. The gross structure of symbiodinolactone A was elucidated by spectroscopic analyses, and the relative configuration was elucidated by the J-based configuration analysis and density-functional theory calculations. Symbiodinolactone A is the new 12-membered macrolide possessing an E double bond between C-4 and C-5, a branched methyl group at C-7, and a 1,2,3-trihydroxybutyl group at C-11. Symbiodinolactone A is the first usual size macrolide and the first non-nitrogen-containing macrolide from dinoflagellate Symbiodinium sp. Symbiodinolactone A might be generated by the unexplained dinoflagellate polyketide biosynthetic machinery.

Antibiotic Resistance of Symbiotic Marine Bacteria Isolated from Marine Organisms in Jeju Island of South Korea

We investigated antibiotics resistance of bacteria isolated from marine organisms in Jeju Island of South Korea. We isolated 17 strains from a marine sponge, algaes, and sea water collected from Biyangdo on Jeju Island. Seventeen strains were analyzed by 16S rRNA gene sequencing for species identification and tested antibiotic susceptibility of strains against six antibiotics. Strain JJS3-4 isolated from S. siliquastrum showed 98% similarity to the 16S rRNA gene of Formosa spongicola A2T and was resistant to six antibiotics. Strains JJS1-1, JJS1-5, JJS2-3, identified as Pseudovibrio spp., and Stappia sp. JJS5-1, were susceptive to chloramphenicol and these four strains belonged to the order Rhodobacterales in the class Alphaproteobacteria. Halomonas anticariensis JJS2-1, JJS2-2 and JJS3-2 and Pseudomonas rhodesiae JJS4-1 and JJS4-2 showed similar resistance pattern against six antibiotics. We could isolate bacteria from marine organisms and their antibiotic resistance investigated, and conducted this study under the premise that such bacteria could produce secondary metabolites that could bring about useful antibiotic effects, resulting in species-specific results. We have a lot of unknown marine resources that we have not been able to explore yet. Bacteria are a valuable resource that can be developed into new useful materials.

New polyketides from dinoflagellate Amphidinium sp.

Marine dinoflagellates have been recognized as a source of novel secondary metabolites with intriguing structures and interesting bioactivities [1]. In our continuing search for bioactive metabolites from Okinawan marine dinoflagellates, we have isolated a series of macrolides, amphidinolides, and long chain polyketides from cultured symbiotic marine dinoflagellates Amphidinium spp. [2]. Recently, we have investigated the culture medium of dinoflagellate Amphidinium sp., which was a symbiont of an acoel flatworm Amphiscolops sp., and isolated five new liner polyketides, amphidinins C˜G (1˜5), with known polyketides, amphidinin A (6) and amphidinolide Q (7) [3 – 5]. The analysis of spectral data revealed that 1˜4 were 4,5-seco-analogs of 7. The absolute configurations of 1˜4 have been elucidated by J-based configuration analysis (JBCA), modified Mosher's method, and chemical derivatization. Compounds 1˜4 corresponded to 4,5-secoamphidinolide Q, 4-O-α-D-ribofuranosyl-4,5-secoamphidinolide Q, 6,O-6-dihydro-4,5-secoamphidinolide Q, and 4-O-α-D-ribo-furanosyl-6,O-6-dihydro-4,5-secoamphidinolide Q, respectively. Compounds 2 and 4 were the first glycoside related to amphidinolides [6]. The structure of 5 was elucidated to be 9,12-O-seco-analog of 6 based on its spectral data. The absolute configuration of 5 has been elucidated to be 2R, 4R, 6S, 11R, and 12S by chemical shift comparison, JBCA, and modified Mosher's method [7]. The absolute configuration of 6 was also elucidated to be 2R, 4R, 6S, 9R, 11R, and 12S by JBCA, modified Mosher's method, and the density-functional theory calculations [8]. Compounds 1, 3, and 7 showed antimicrobial activities against some bacteria and fungi. Compounds 2 (IC50 16 µg/mL), 4 (IC50 32 µg/mL), and 5 (IC50 8 µg/mL) showed selective antifungal activity against Trichophyton mentagrophytes. Compound 6 showed antibacterial activity against Bacillus subtilis (MIC 16 µg/mL) and antifungal activity against Aspergillis niger (IC50 4 µg/mL).

Assessment of Anabaena sp. Strain PCC 7120 as a Heterologous Expression Host for Cyanobacterial Natural Products: Production of Lyngbyatoxin A.

Cyanobacteria are well-known producers of natural products of highly varied structure and biological properties. However, the long doubling times, difficulty in establishing genetic methods for marine cyanobacteria, and low compound titers have hindered research into the biosynthesis of their secondary metabolites. While a few attempts to heterologously express cyanobacterial natural products have occurred, the results have been of varied success. Here, we report the first steps in developing the model freshwater cyanobacterium Anabaena sp. strain PCC 7120 (Anabaena 7120) as a general heterologous expression host for cyanobacterial secondary metabolites. We show that Anabaena 7120 can heterologously synthesize lyngbyatoxin A in yields comparable to those of the native producer, Moorea producens, and detail the design and use of replicative plasmids for compound production. We also demonstrate that Anabaena 7120 recognizes promoters from various biosynthetic gene clusters from both free-living and obligate symbiotic marine cyanobacteria. Through simple genetic manipulations, the titer of lyngbyatoxin A can be improved up to 13-fold. The development of Anabaena 7120 as a general heterologous expression host enables investigation of interesting cyanobacterial biosynthetic reactions and genetic engineering of their biosynthetic pathways.

Should I stay or should I go? Causes and dynamics of host desertion by a parasitic crab living on echinoids

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 546:163-171 (2016) - DOI: https://doi.org/10.3354/meps11616 Should I stay or should I go? Causes and dynamics of host desertion by a parasitic crab living on echinoids C. De Bruyn1,2, B. David2,3, S. Motreuil2, G. Caulier4, Q. Jossart1, T. Rigaud2, C. De Ridder1 1Laboratoire de Biologie Marine (CP 160/15), Université Libre de Bruxelles (ULB), 50 avenue F. D. Roosevelt, 1050 Brussels, Belgium 2Laboratoire Biogéosciences, UMR CNRS 6282, Université Bourgogne Franche-Comté, 6 boulevard Gabriel, 21000 Dijon, France 3Muséum national d’Histoire naturelle, 57 rue Cuvier, 75005 Paris, France 4Laboratoire de Biologie des Organismes Marins et Biomimétisme, Université de Mons, 20, Place du Parc, 7000 Mons, Belgium *Corresponding author: cridder@ulb.ac.be ABSTRACT: In some long-living symbiotic species, movements between hosts are not limited to offspring since adult parasites can move from one individual host to another one. Host-switching may be driven by different parameters such as (1) mating strategies of symbionts, (2) foraging for resources or (3) avoiding overcrowded or diseased/dead host. Symbiotic marine crustaceans are suitable models to understand what underlies host-switching behavior. In this study, we investigated host desertion by the parasitic pea crab Dissodactylus primitivus associated with the echinoid host Meoma ventricosa. Mark-recapture field experiments, during which crabs were almost always found on their host in heterosexual combinations, suggest that host desertion occurs less frequently when 2 crabs (compared to 3) share the same host. During laboratory experiments with high crab density, the proportion of crabs leaving an echinoid was low when the 2 genders of crabs were present on the host, compared to 1 gender only (males or females). This suggests that host desertion is mostly driven by intersex selection and the search for a mate and, to a lesser extent, by competition between crabs. However, both field and laboratory experiments showed evidence that when they switch host, most crabs remained for a while in the sediment underneath their host. We propose that this behavior, associated with the aggregative behavior of their hosts, would allow the crabs to solve the trade-off between staying on their hosts (therefore suffering overcrowding and sub-optimal mate search) and moving too far from the host (therefore suffering loss of food source and high predation risk). KEY WORDS: Symbiosis · Mobile invertebrates · Host-switching · Mating systems · Pea crab · Echinoid Full text in pdf format PreviousNextCite this article as: De Bruyn C, David B, Motreuil S, Caulier G, Jossart Q, Rigaud T, De Ridder C (2016) Should I stay or should I go? Causes and dynamics of host desertion by a parasitic crab living on echinoids. Mar Ecol Prog Ser 546:163-171. https://doi.org/10.3354/meps11616 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 546. Online publication date: March 21, 2016 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2016 Inter-Research.