Commensal Association Research Articles

Cyclic Diguanylate in the Wild: Roles During Plant and Animal Colonization.

Cyclic diguanylate (c-di-GMP) is a near-ubiquitous signaling molecule that regulates the motility-to-sessility transition in many bacterial species. Among the phenotypes influenced by c-di-GMP are biofilm formation, motility, cell cycle, and virulence. The hallmark phenotypes regulated by c-di-GMP-biofilm formation and motility-are key determinants of host-bacterial interactions. A large body of research has identified the roles of c-di-GMP in regulating phenotypes in culture. While numerous studies have investigated roles for c-di-GMP during the establishment and maintenance of pathogenic host-bacterial associations, considerably less attention has been devoted to defining the roles of c-di-GMP during beneficial and commensal associations. This review describes the known roles of c-di-GMP in regulating phenotypes that contribute to host colonization, with a focus on knowledge gaps and future prospects for examining c-di-GMP during beneficial colonization.

Sexual Biology and Mating Behaviour in Decapod Crustaceans: A Case Study with Coral Reef Dwelling Caridean Shrimps

Crustaceans have diversified sexual systems, incorporating various reproductive modalities such as gonochorism and a wide variety of hermaphroditism. In particular, the coral reef- dwelling caridean shrimps, living in symbiosis with other marine invertebrates, have developed unusual sexual systems that have given origin to a range of social systems, including the highly advanced eusociality. Protandric hermaphroditism, common among the caridean shrimps, has also reached a unique sexual condition, known as protandric simultaneous hermaphroditism, in the genus, Lysmata. Similarly, mating systems in the caridean shrimps are highly diverse and divergent. In addition, their occurrence in the coral reef shrimps is correlated to their life style adaptations such as their commensal association with other invertebrates. Other ecological factors like the predation risk from outside of the host animals and differences in the host characteristics may also be the driving forces in determining mating associations. Furthermore, the transition from sexual monogamy to social monogamy under conditions of their symbiotic life led to complex community living in several synalpheid shrimps. Understandably, the existence of various sexual and mating systems in these caridean shrimps has a dependence on the eco- social conditions prevalent in the coral reef biota.

Ecological factors driving the feather mite associations in tropical avian hosts

Birds host a diversity of ectosymbionts including feather‐dwelling arthropods such as feather mites and lice that they have co‐evolved and speciated with. Among these ectosymbionts, feather mites have evolved more mutualistic to commensal associations with birds than other groups. However, our understanding of the biological and ecological drivers that shape the associations between avian hosts and feather mites in tropical communities is poor. Thus, to help fill this knowledge gap we investigated the factors that govern feather mite abundances at host community, host species and individual levels in bird communities from different elevations on the tropical island of New Guinea. We examined the effects of abiotic factors, such as temperature and precipitation, the influence of host species, feeding guilds, bill morphology, body region, body conditions and infections with haemosporidian blood parasites on feather mite abundance. We found that feather mites were very prevalent among New Guinean birds and that mite abundance was not significantly different between elevations. Bird species with curved bills experienced significantly lower number of mites compared to species with straight bills. Feather mite abundance was significantly higher on flight feathers than on the rest of the body and mite abundance was not strongly associated with the body condition of individuals in most host species, except for a significant negative relationships in three species. Moreover, we did not find an association between feather mite abundance and blood parasite infections, potentially indicating a non‐synergistic association of these two symbionts. Overall, our study demonstrates that tropical avian‐feather mite associations are driven by different biotic and abiotic factors at host community, species and individual levels, highlighting the importance of examining these associations at both broad and fine scales to thoroughly understand the evolution of these symbioses.

Commensal Pseudomonas fluorescens Strains Protect Arabidopsis from Closely Related Pseudomonas Pathogens in a Colonization-Dependent Manner.

ABSTRACTPlants form commensal associations with soil microorganisms, creating a root microbiome that provides benefits, including protection against pathogens. While bacteria can inhibit pathogens through the production of antimicrobial compounds in vitro, it is largely unknown how microbiota contribute to pathogen protection in planta. We developed a gnotobiotic model consisting of Arabidopsis thaliana and the opportunistic pathogen Pseudomonas sp. N2C3, to identify mechanisms that determine the outcome of plant-pathogen-microbiome interactions in the rhizosphere. We screened 25 phylogenetically diverse Pseudomonas strains for their ability to protect against N2C3 and found that commensal strains closely related to N2C3, including Pseudomonas sp. WCS365, were more likely to protect against pathogenesis. We used comparative genomics to identify genes unique to the protective strains and found no genes that correlate with protection, suggesting that variable regulation of components of the core Pseudomonas genome may contribute to pathogen protection. We found that commensal colonization level was highly predictive of protection, so we tested deletions in genes required for Arabidopsis rhizosphere colonization. We identified a response regulator colR, and two ColR-dependent genes with predicted roles in membrane modifications (warB and pap2_2), that are required for Pseudomonas-mediated protection from N2C3. We found that WCS365 also protects against the agricultural pathogen Pseudomonas fuscovaginae SE-1, the causal agent of bacterial sheath brown rot of rice, in a ColR-dependent manner. This work establishes a gnotobiotic model to uncover mechanisms by which members of the microbiome can protect hosts from pathogens and informs our understanding of the use of beneficial strains for microbiome engineering in dysbiotic soil systems.

Interspecific foraging association between the cryptic forest-falcon, Micrastur mintoni and primates in an Amazon rainforest in Brazil

ABSTRACT Following behavior is a well-documented foraging specialization in Neotropical birds, which consists of individuals of solitary or mixed-flocking species following other moving animals to capture fleeing prey. Here, we report two observations of the cryptic forest-falcon, Micrastur mintoni following troops of primates during an ornithological inventory in the eastern Brazilian Amazon. During both observations, the falcon emitted a typical vocalization and captured fleeing insects dispersed by the primates moving through the forest while foraging. This is the first report of an apparently commensal association between a Micrastur forest falcon and two species of primates.

Commensal association of the common kingfisher with foraging Eurasian otters

AbstractPositive interactions between birds and mammals are a fascinating aspect of animal behaviour. Feeding associations may consist of local enhancement or facilitation, and in the latter case, of commensalism or mutualism depending on the benefits received by the facilitator. We report here on a previously undescribed feeding association between piscivorous birds and Eurasian otters Lutra lutra. In Spain, common kingfisher Alcedo atthis and grey heron Ardea cinerea were observed closely following foraging otters and benefited from feeding opportunities provided by these. Behavioural observations of otters in central Spain (28.4 hr; 19 days) revealed that an association with kingfishers occurred in 33% of otter foraging events (n = 92). Simultaneous observations in northern Spain (14.2 hr; 16 days) showed an association between otters and kingfishers or grey herons in 41.6% and 11.7% of otter foraging events (n = 77), respectively. The association probability between kingfishers and otters increased significantly when otters foraged closer to the shore and on small fish rather than other prey (crayfish or large fish). Birds fed on prey remain left by the feeding otters, on small fish captured by otters when these were satiated and playing, or on prey displaced by otters. Our observations are consistent with facilitation and commensalism: piscivorous birds gained feeding opportunities provided by the otters, with no apparent costs or benefits to the latter. Similar feeding associations have been described between other species of otters and piscivorous birds (kingfishers, herons, egrets, storks) in Asia, South America and Southern Africa, but had not yet been described in Europe. The occurrence of piscivorous bird–otter associations in different species and regions suggests that this commensalism may be often overlooked but widespread. We have shown that the association can be frequent and is context‐dependent, with benefits for associating birds depending on otters´ behaviour and targeted prey.

Amelioration of biomass and lipid in marine alga by an endophytic fungus Piriformospora indica

BackgroundMany studies have been carried out on the growth-modulating efficiency of plants by the colonization of an endophytic fungus Piriformospora indica. However, studies involving the co-culture of alga with endophytic fungal strains for enhanced biodiesel production are rare. In this study, the interaction between P. indica and Parachlorella kessleri-I, a marine algal strain, was assessed at metabolic level.ResultsIn association with an endophytic fungus, the algal biomass enhanced from 471.6 to 704 mg/L, and the fatty acid methyl ester (FAME) profile of P. kessleri-I increased substantially. In case of FAME profile of co-cultured P. kessleri-I, two essential components of biodiesel, i.e. elaidic acid and oleic acid, increased by 1.4- and 1.8-fold, respectively. To ascertain changes in the metabolic profile of P. kessleri-I by P. indica co-culture, gas chromatography–mass spectrometry (GC–MS)-based untargeted metabolomics study was performed to identify the metabolites involved; and differential nature of the essential metabolites was also confirmed using HPLC and LC–MS. Significant modulation of the bioactive metabolites such as succinate, oxo-propanoate, l-alanine, glutamate, acetate and 1,2 propanediol, hydroxy butane was observed.ConclusionThe metabolites like glutamate and succinate that usually belong to the GABA shunt pathway were observed to be upregulated. The pathway links nitrogen metabolism and carbon metabolism, thus influencing the growth and lipid profile of the algae. These differential metabolites thus indicated the important commensal association between the endophytic fungus and autotrophic marine alga, and established that endophytic fungus can be handy for the sustainability of algal biofuel industries.

Association between deep-water scale-worms (Annelida: Polynoidae) and black corals (Cnidaria: Antipatharia) in the Southwestern Atlantic

Polynoid scale-worms have been found living as commensals with deep-water antipatharians (commonly known as black corals) in the Potiguar Basin, off Rio Grande do Norte State, Northeastern Brazil. In this paper two polychaete species and four black corals species are redescribed. Benhamipolynoecf.antipathicola and Parahololepidellacf.greeffi, and the black coral Stylopathesadinocrada Opresko, 2006 are recorded for the Southwestern Atlantic. Benhamipolynoecf.antipathicola was first described from off New Zealand and the Malay Archipelago, as symbiont with the black coral Stylopathestenuispina (Silberfeld, 1909). It was later reported for the North Atlantic, off Florida, associated with Stylopathescolumnaris (Duchassaing, 1870). In our study, B.cf.antipathicola was found in association with the black coral S.adinocrada. Parahololepidellacf.greeffi was first described as a free-living from shallow waters off São Tomé and Cabo Verde Islands, West Africa, and later reported as symbiont with the black coral Tanacetipathescf.spinescens in the same location. Our data expand both the geographical distribution and the host range of this species which is reported for the first time as symbiont with Tanacetipathesbarbadensis (Brook, 1889), T.tanacetum (Pourtalès, 1880) and T.thamnea (Warner, 1981) in Brazil. The aim of this study is to discuss commensal associations between two species of scale-worm polynoids and black corals found in the Southwestern Atlantic, and also reporting their global distribution. Finally, we provided an updated list of the commensal polynoids and their black coral hosts.

A guinea fowl genome assembly provides new evidence on evolution following domestication and selection in galliformes.

The helmeted guinea fowl Numida meleagris belongs to the order Galliformes. Its natural range includes a large part of sub‐Saharan Africa, from Senegal to Eritrea and from Chad to South Africa. Archaeozoological and artistic evidence suggest domestication of this species may have occurred about 2,000 years BP in Mali and Sudan primarily as a food resource, although villagers also benefit from its capacity to give loud alarm calls in case of danger, of its ability to consume parasites such as ticks and to hunt snakes, thus suggesting its domestication may have resulted from a commensal association process. Today, it is still farmed in Africa, mainly as a traditional village poultry, and is also bred more intensively in other countries, mainly France and Italy. The lack of available molecular genetic markers has limited the genetic studies conducted to date on guinea fowl. We present here a first‐generation whole‐genome sequence draft assembly used as a reference for a study by a Pool‐seq approach of wild and domestic populations from Europe and Africa. We show that the domestic populations share a higher genetic similarity between each other than they do to wild populations living in the same geographical area. Several genomic regions showing selection signatures putatively related to domestication or importation to Europe were detected, containing candidate genes, most notably EDNRB2, possibly explaining losses in plumage coloration phenotypes in domesticated populations.

Whole Cell Cross-Linking to Discover Host-Microbe Protein Cognate Receptor/Ligand Pairs.

Bacterial surface ligands mediate interactions with the host cell during association that determines the specific outcome for the host–microbe association. The association begins with receptors on the host cell binding ligands on the microbial cell to form a partnership that initiates responses in both cells. Methods to determine the specific cognate partnerships are lacking. Determining these molecular interactions between the host and microbial surfaces are difficult, yet crucial in defining biologically important events that are triggered during association of the microbiome, and critical in defining the initiating signal from the host membrane that results in pathology or commensal association. In this study, we designed an approach to discover cognate host–microbe receptor/ligand pairs using a covalent cross-linking strategy with whole cells. Protein/protein cross-linking occurred when the interacting molecules were within 9–12 Å, allowing for identification of specific pairs of proteins from the host and microbe that define the molecular interaction during association. To validate the method three different bacteria with three previously known protein/protein partnerships were examined. The exact interactions were confirmed and led to discovery of additional partnerships that were not recognized as cognate partners, but were previously reported to be involved in bacterial interactions. Additionally, three unknown receptor/ligand partners were discovered and validated with in vitro infection assays by blocking the putative host receptor and deleting the bacterial ligand. Subsequently, Salmonella enterica sv. Typhimurium was cross-linked to differentiated colonic epithelial cells (caco-2) to discover four previously unknown host receptors bound to three previously undefined host ligands for Salmonella. This approach resulted in a priori discovery of previously unknown and biologically important molecules for host/microbe association that were casually reported to mediate bacterial invasion. The whole cell cross-linking approach promises to enable discovery of possible targets to modulate interaction of the microbiome with the host that are important in infection and commensalism, both of with initiate a host response.

Evolution of a Vegetarian Vibrio: Metabolic Specialization of Vibrio breoganii to Macroalgal Substrates.

While most Vibrionaceae are considered generalists that thrive on diverse substrates, including animal-derived material, we show that Vibrio breoganii has specialized for the consumption of marine macroalga-derived substrates. Genomic and physiological comparisons of V. breoganii with other Vibrionaceae isolates revealed the ability to degrade alginate, laminarin, and additional glycans present in algal cell walls. Moreover, the widely conserved ability to hydrolyze animal-derived polymers, including chitin and glycogen, was lost, along with the ability to efficiently grow on a variety of amino acids. Ecological data showing associations with particulate algal material but not zooplankton further support this shift in niche preference, and the loss of motility appears to reflect a sessile macroalga-associated lifestyle. Together, these findings indicate that algal polysaccharides have become a major source of carbon and energy in V. breoganii, and these ecophysiological adaptations may facilitate transient commensal associations with marine invertebrates that feed on algae.IMPORTANCE Vibrios are often considered animal specialists or generalists. Here, we show that Vibrio breoganii has undergone massive genomic changes to become specialized on algal carbohydrates. Accompanying genomic changes include massive gene import and loss. These vibrios may help us better understand how algal biomass is degraded in the environment and may serve as a blueprint on how to optimize the conversion of algae to biofuels.

Interspecific Associations between Two Woodcreeper Species (Dendrocolaptinae) and a Group of Black-Faced Lion Tamarins (Primates, Callitrichinae)

Woodcreepers are insectivorous birds that eventually form feeding associations with other species to complement their energy intake. Here we present quantitative data on a possible commensal association between two woodcreeper species, the Eastern Olivaceous Woodcreeper Sittasomus griseicapillus and the Pale-winged Woodcreeper Dendrocincla turdina, and a Neotropical monkey, the Black-faced Lion Tamarin Leontopithecus caissara, at Superagui National Park, Brazil. Our aim is to bring new information on bird/monkey associations in order to achieve a better understanding of the functional basis leading to the occurrence of these associations. We never observed the two woodcreeper species following monkeys at the same time and we found a significant difference between the mean height in which each bird species associated with monkeys. We did not observe interspecific aggressions between woodcreepers and monkeys. Birds benefited from flushed prey, and we did not find evidence that monkeys have benefits or incur costs due to their association with birds, suggesting that these associations may be characterised as a form of commensalism. —Moro-Rios, R.F., Silva-Pereira, J.E., Ludwig, G. & Gomes Barriento, F. (2018). Interspecific association between two Woodcreeper species (Dendrocolaptinae) and a group of Black-faced Lion Tamarins (Primates, Callitrichinae). Ardeola, 65: 299–304.

Diversity and abundance of conspicuous macrocrustaceans on coral reefs differing in level of degradation.

Coral reefs sustain abundant and diverse macrocrustaceans that perform multiple ecological roles, but coral reefs are undergoing massive degradation that may be driving changes in the species composition and abundance of reef-associated macrocrustaceans. To provide insight into this issue, we used non-destructive visual census techniques to compare the diversity and abundance of conspicuous macrocrustaceans (i.e., those >1 cm and visible without disturbance) between two shallow Caribbean coral reefs similar in size (∼1.5 km in length) and close to each other, but one (“Limones”) characterized by extensive stands of the branching coral Acropora palmata, and the other (“Bonanza”) dominated by macroalgae and relic coral skeletons and rubble (i.e., degraded). We also assessed the structural complexity of each reef and the percent cover of various benthic community components. Given the type of growth of A. palmata, we expected to find a greater structural complexity, a higher cover of live coral, and a lower cover of macroalgae on Limones, and hence a more diverse and abundant macrocrustacean community on this reef compared with Bonanza. Overall, we identified 63 macrocrustacean species (61 Decapoda and two Stomatopoda). Contrary to our expectations, structural complexity did not differ significantly between the back-reef zones of these reefs but varied more broadly on Limones, and the diversity and abundance of macrocrustaceans were higher on Bonanza than on Limones despite live coral cover being higher on Limones and macroalgal cover higher on Bonanza. However, the use of various types of microhabitats by macrocrustaceans differed substantially between reefs. On both reefs, the dominant species were the clinging crab Mithraculus coryphe and the hermit crab Calcinus tibicen, but the former was more abundant on Bonanza and the latter on Limones. M. coryphe occupied a diverse array of microhabitats but mostly coral rubble and relic skeletons, whereas C. tibicen was often, but not always, found associated with colonies of Millepora spp. A small commensal crab of A. palmata, Domecia acanthophora, was far more abundant on Limones, emerging as the main discriminant species between reefs. Our results suggest that local diversity and abundance of reef-associated macrocrustaceans are partially modulated by habitat degradation, the diversity of microhabitat types, and the establishment of different commensal associations rather than by structural complexity alone.

Extension of the geographical distribution of the crab Asthenognathus atlanticus Monod, 1932, in the eastern English Channel through its commensal relationship with the polychaete Chaetopterus variopedatus (Renier, 1804)

Asthenognathus atlanticus Monod, 1932, is reported here for the first time in the area around Dieppe-Le Treport (Normandy coast in the eastern part of the English Channel). A total of 26 specimens were collected in 2015–2016 from fine and coarse sands at water depths between 12 and 25 m. Two specimens were found in the stomach of two thornback rays Raja clavata. The eastward progression of A. atlanticus is consistent with tidal residual currents in the English Channel. The period of global warming is likely favorable for this easterly progression, and the species could reach the southern part of the North Sea in a few years. Our observations in the eastern part of the English Channel also illustrate a new commensal association between the tubicolous polychaete C. variopedatus and the crab A. atlanticus, the latter being found in a variety of soft-bottom sediments ranging from muddy to coarse sands, in agreement with reports of its presence in the Rade de Cherbourg and the Bay of Seine.

Co-occurrence and commensal feeding between Little Egrets Egretta garzetta and Eurasian Spoonbills Platalea leucorodia

ABSTRACTCapsule: The spatial distribution and feeding efficiency of Little Egrets Egretta garzetta wintering in the gulf of Gabès, Tunisia, are affected by a commensal association with the Eurasian Spoonbills Platalea leucorodia.Aims: To investigate the role of the interspecific interaction between Little Egrets and Eurasian Spoonbills in shaping the spatial distribution and feeding efficiency of Little Egrets.Methods: Using count and behavioural data, we examined the co-occurrence of these species in flocks, and compared the foraging efficiency of Little Egrets feeding with Eurasian Spoonbills with that of solitary Little Egrets.Results: We found that the presence of Eurasian Spoonbills doubled the chance of Little Egrets being present. Within mixed flocks, the number of Little Egrets increased with the number of Spoonbills. Moreover, Little Egrets foraging in association with Eurasian Spoonbills took fewer steps, had higher pecking rates and higher prey intake rates than solitary Little Egrets.Conclusion: Little Egrets appear to obtain foraging efficiency benefits by following Eurasian Spoonbills. This interaction seems to play a role in determining the spatial distribution of Little Egrets.

Borniopsis mortoni sp. n. (Heterodonta, Galeommatoidea, Galeommatidaesensu lato), a new bivalve commensal with a synaptid sea cucumber from Japan.

The Galeommatoidea is a bivalve superfamily that exhibits high species diversity in shallow waters. Many members of this superfamily are associated commensally with burrowing marine invertebrates in benthic sediments. The genus Borniopsis is known only from eastern Asia and exhibits high host diversity (e.g., mantis shrimps, crabs, holothurians, sipunculans and echiurans). A new species, Borniopsis mortoni sp. n., is described from mud flats at the mouth of the Souzu River, southwestern Shikoku Island, Japan. This species has elongate-ovate shells covered by a tan to dark brown periostracum, and lives attached by both its foot and byssal threads to the body surface of the synaptid sea cucumber Patinapta ooplax. Several individuals of Borniopsis mortoni are often found on the same host, but sometimes more than 10 individuals can occur together. Borniopsis mortoni is one of the smallest species in this genus. Probably, its small body size is an adaptation to the mode of life in a narrow host burrow. Until now, only two other Borniopsis species were known to have commensal associations with synaptids. Thus, this is the third example of a synaptid-associated species from this genus. In addition, we briefly review the galeommatoideans commensal with apodid sea cucumbers.

Gut Microbiota: A Contributing Factor to Obesity.

Obesity, a global epidemic of the modern era, is a risk factor for cardiovascular diseases (CVD) and diabetes. The pervasiveness of obesity and overweight in both developed as well as developing populations is on the rise and placing a huge burden on health and economic resources. Consequently, research to control this emerging epidemic is of utmost importance. Recently, host interactions with their resident gut microbiota (GM) have been reported to be involved in the pathogenesis of many metabolic diseases, including obesity, diabetes, and CVD. Around 1014 microorganisms reside within the lower human intestine and many of these 1014 microorganisms have developed mutualistic or commensal associations with the host and actively involved in many physiological processes of the host. However, dysbiosis (altered gut microbial composition) with other predisposing genetic and environmental factors, may contribute to host metabolic disorders resulting in many ailments. Therefore, delineating the role of GM as a contributing factor to obesity is the main objective of this review. Obesity research, as a field is expanding rapidly due to major advances in nutrigenomics, metabolomics, RNA silencing, epigenetics, and other disciplines that may result in the emergence of new technologies and methods to better interpret causal relationships between microbiota and obesity.

New records and field observations support a facultative commensal association of <I>Thalamita longifrons</I> and <I>Thalamita murinae</I> with soft coral

New records and field observations support a facultative commensal association of <I>Thalamita longifrons</I> and <I>Thalamita murinae</I> with soft coral

Stingrays as possible facilitators for foraging trevallies in a nearshore sandflat

Mixed-species associations are temporary aggregations of individuals of different species that are driven by improved foraging, anti-predator benefits, and host/ cleaner relationships (Morse 1977). Host/cleaner relationships are common among fishes, including between elasmobranchs and teleosts (Papastamatiou et al. 2007). However, the function of associations between teleosts and elasmobranchs for other purposes is poorly described (Heithaus et al. 2010). On 27 April 2013, in the waters of Petite-Terre, along the north shore of Terre de Bas (Guadeloupe archipelago, 16°10’23.10”N, 61°06’32.41”W), a ∼90 cm (disk width) southern stingray (Dasyatis americana) was observed (∼15 min) and filmed (102 s) in association with a ∼40 cm bar jack (Caranx ruber). The observation occurred at 340 pm in shallow waters (<1.5 m) over a sandflat that is adjacent to a coral reef ecosystem. Video footage shows the jack swimming above the ray and actively maintaining the association during periods when the ray stopped to forage or changed headings (Fig. 1a, see supplementary material). During extractive foraging by the ray, the jack was observed inspecting the sand plume expelled by the ray and striking at prey that were dislodged (Fig. 1b). It therefore appears that the jack was associated to the stingray to forage and may have been able to access otherwise unavailable resources. Similar commensal associations were observed in the Pacific Ocean by two of the authors (JJK and JPQ), where trevallies were associated with stingrays for foraging purposes : a t Cocos Is land (5°31 ’08 ’N, 87°04’18”W), involving the bluefin trevally (Caranx melampygus) and the black-spotted stingray (Taeniurops meyeni), and in the lagoon of Tetiaroa, French Polynesia (17°0’S, 149°33”W), where several associations between pink whiprays (Himantura fai) and both bluefin and giant trevallies (Caranx ignobilis) were observed. Stingrays were always alone, but up to three trevallies could be observed with a single ray. In several of these cases, trevallies were seen lunging in plumes created by rays. Although other benefits to trevallies (e.g. reduced predation risk) cannot be discounted, we hypothesize that rays constitute facilitators for foraging trevallies. As documented for other batoids such as bat rays (Myliobatus californica) and round stingrays (Urobatis halleri) (VanBaricom 1982; Heithaus et al. 2010), stingrays in coral reef ecosystems may facilitate other predators that take advantage of prey that are disturbed or excavated during ray foraging. Electronic supplementary material The online version of this article (doi:10.1007/s12526-014-0304-6) contains supplementary material, which is available to authorized users.

A new Fenestrulina (Bryozoa, Cheilostomata) commensal with tube-dwelling anemones (Cnidaria, Ceriantharia) in the tropical southwestern Atlantic.

A new species of cheilostome bryozoan, Fenestrulina commensalis n. sp., was collected in December 2008 by scuba at 5-10 meters depth at Guaibura Beach, Guarapari, Espírito Santo state, southeastern Brazil. The specimen was found associated with tubes of the cerianthid Pachycerianthus sp., representing the first commensal association between a bryozoan and a tube-dwelling anemone. Fenestrulina commensalis n. sp. is the third species of the genus found in Brazilian waters; it is distinguished from other Atlantic species of Fenestrulina by its small angular orificial condyles, a single oral spine and basal anchoring rhizoids arising from abfrontal pore chambers. Morphological adaptations to encrust the tubes of cerianthids include anchoring rootlets and weakly contiguous zooids. These morphological features allow the colony the flexibility to grow around the tube and feed relatively undisturbed by silt and detritus, being raised well above the soft-sediment substratum in which the tube-anemone grows.