Commensal Association Research Articles

Hyas spp. crabs and sea anemones—new species associations from Svalbard

In the literature, there is a large amount of evidence on mutual and commensal associations between actiniarians and decapods (see Ross 1983 and references therein). Among all these studies, only Davenport (1962) and Schrieken (1965) dealt with Hyas spp. Their work, however, was performed in aquaria and concerned only young crab individuals (Davenport 1962) and a single sea anemone species—Tealia felina (Linnaeus, 1767) (= Urticina felina) (Davenport 1962; Schrieken 1965). Here, we describe the association of mature H. araneus (Linnaeus, 1758) and H. coarctatus Leach, 1816 with Cribrinopsis similis Carlgren, 1921, Hormathia nodosa (Fabricius, 1780) and Urticina crassicornis (O.F. Mueller, 1776), which to our knowledge are reported for the first time. The associations were recorded during the summers of 2011 and 2012 on the rocky bottom of an Arctic fjord—Isfjord (Spitsbergen Island, Svalbard Archipelago) at 10–15 m depth. Direct underwater observations (Fig. 1a–h) indicate that the crabs were in contact with sea anemones for several minutes. When approached by a diver, the crabs did not escape from the anemone but got closer to it. On one specific occasion, removing the rock, marked in Fig. 1g with an arrow, revealed a large (∼5 cm diameter of the pedal disc) specimen ofC. similis attached to the crab by its verrucae (Fig. 1h). Although sufficiently large sea anemones such as Urticina sp. have occasionally been noted in the past to feed on these crabs in this area (Gulliksen and Svensen 2004), it seems instead that the crabs, while avoiding contact with the tentacles, are searching for protection from predators (e.g. bottom-dwelling fish, octopus) as previously reported for other decapods, including those closely related toHyas spp. (Ross 1983). More studies are needed to verify and confirm whether these associations have just a short-term facultative commensalistic character.

TLR5 Stops Commensals in Their Tracks

IgA antibodies help maintain intestinal immune homeostasis with resident commensal species; however, the precise mechanisms regulating IgA induction and the epitopes recognized by these antibodies remain incompletely understood. In this issue of Cell Host & Microbe, Tyler et al. (2013) demonstrate that TLR5-dependent induction of anti-flagellin antibodies prevents commensal association with the intestinal mucosa by limiting bacterial motility.

Rogerella isp. Infesting the Pore Pairs of Hemipneustes striatoradiatus (Leske) (Echinoidea: Upper Cretaceous, Belgium)

An otherwise well-preserved test of the holasteroid echinoid Hemipneustes striatoradiatus (Leske) from the Emael Member, Maastricht Formation (Maastrichtian, Upper Cretaceous) of Belgium, is infested by encrusting bivalves and foraminiferans and the boring Rogerella isp. In this specimen, Rogerella preferentially infested and modified the ambulacral pore pairs of the echinoid close to the apex. This was not a commensal association. The echinoid test shows no growth deformations in response to this invasion; pore pairs are locally strongly infested; and encrusting invertebrates testify to the long post-mortem residence time of the test on the sea floor. Rather, the pore pairs of the dead echinoid were crannies attractive to settling larvae of acrothoracian barnacles, the producers of Rogerella.

Commensal association of piscivorous birds with foraging otters in southeastern Brazil, and a comparison with such a relationship of piscivorous birds with cormorants

Associations of birds with foraging otters are restricted to four records in different regions of the world. We report herein on piscivorous birds associated with foraging otters (Lontra longicaudis) in a pool at an urban park in southeastern Brazil. We recorded up to ˜30 individuals of seven piscivorous bird species associated with a single otter. The mammals searched for fish prey in the pool, causing fish to surface or flee to the shallows, and the birds preyed on the disturbed fish. The bird assemblages we recorded associated with otters are the richest ones reported to date both in number of species and individuals. The bird species associated with otters were the same that followed cormorants (Phalacrocorax brasilianus) in a large pond adjacent to the pool. The foraging of cormorants and otters may be considered as functionally equivalent, because both predators chase prey underwater, surface periodically, and cause fish to flee.

Bonsai anemones: Growth suppression of sea anemones by their associated kleptoparasitic boxer crab

Kleptoparasitism, the theft of food, is a foraging strategy often overlooked or misinterpreted as a commensal association. Crabs of the genus Lybia, commonly known as boxer crabs, hold a pair of tiny sea anemones in their claws. The nature of this seemingly commensal association has never been tested empirically. In a laboratory study of food consumption, we show that the boxer crabs Lybia leptochelis regulate the size of their claw-held sea anemones (Alicia sp.). The anemone size is regulated by: (a) distancing the held anemones from presented food – and in the event any food particles are caught – (b) using rapid leg movements to remove most of the food captured by either anemone. Anemones removed from the crabs and grown independently underwent remarkable changes in morphology, color, and size, with over 250% expansion in pedal-disk diameter. The ultimate aim of classical kleptoparasitism is food acquisition by the pirate. We have shown a completely new role of kleptoparasitism, in which the victim is not only robbed of food, but is also regulated in size. The boxer crab thus maintains a “Bonsai” symbiont that is conveniently carried around as a tool to trap its food and provide protection.

An offer you cannot refuse: down‐regulation of immunity in response to a pathogen's retaliation threat

According to the Red Queen hypothesis, hosts and pathogens are engaged in an escalating coevolutionary arms race between resistance and virulence. However, the vast majority of symbionts colonize their hosts' mucosal compartments without triggering any immune response, resulting in durable commensal associations. Here, I propose a simple extension of previous mathematical models for antagonistic coevolution in which the host can mount a delayed immune response; in response, the symbiont can change its virulence following this activation. Even though the levels of virulence in both phases are assumed to be genetically determined, this simple form of plasticity can select for commensal associations. In particular, coevolution can result in hosts that do not activate their immune response, thus preventing phenotypically plastic pathogens from switching to a higher virulence level. I argue that, from the host's point of view, this state is analogous to the mafia behaviour previously described in avian brood parasites. More importantly, this study provides a new hypothesis for the maintenance of a commensal relationship through antagonistic coevolution.

Does the Bananaquit Benefit Commensally from Parrot Frugivory? An Assessment Using Habitat Quality

AbstractHow strong‐beaked frugivores such as parrots affect other frugivores is poorly understood. This study quantitated six indices of habitat quality for the facultatively frugivorous Bananaquit (Coereba flaveola) using two habitat types and three treatments of habitat quality, namely old growth forest versus citrus orchards in Dominica, the latter habitat type with and without parrot frugivory. The study also controlled for elevation, rainfall and citrus fruit maturity. The results indicate that both the quantity of parrot frugivory and fruit maturity at the time of frugivory influenced the habitat quality for Bananaquits. Their abundance was higher, individuals stored more fat, and parasite loads were lower on farms with more parrot frugivory. Fruit quality mediated the influence of the quantity of parrot frugivory insofar as Bananaquit body condition was tightly correlated with the fruit chemistry at the time of frugivory or harvest. This study provides empirical evidence of a commensal association and underscores the important ecological role of Neotropical psittacines as mediators of habitat quality for other animal. The findings further suggest that loss of these apex consumers may have triggered previously unappreciated trophic cascades, particularly in island ecosystems lacking large mammalian canopy frugivores.

Infection of Dreissena polymorpha (Bivalvia: Dreissenidae) with Conchophthirus acuminatus (Ciliophora: Conchophthiridae) in lakes of different trophy

The freshwater invasive mollusc Dreissena polymorpha and its host-specific commensal ciliate Conchophthirus acuminatus represent a convenient model to study various aspects of symbiotic relationships. This study was conducted to test whether the nutrient enrichment of waterbodies inhabited by D. polymorpha is associated with C. acuminatus infection. Three lakes differing in their trophic conditions were simultaneously sampled to estimate the levels of C. acuminatus infection in D. polymorpha (eutrophic Lake Batorino, moderately eutrophic Lake Myastro, and mesotrophic Lake Naroch, Republic of Belarus). Although the percentage of infected molluscs did not differ among these waterbodies, the average number of ciliates per host showed a significant increase with respect to the lake trophic status. This pattern could be explained by favorable feeding conditions experienced by D. polymorpha and its commensal C. acuminatus in waters of higher trophy. In particular, the average size of D. polymorpha (i.e., carrying capacity for the infection) significantly positively correlated with the lake trophic status. Higher trophy could also directly affect reproduction potential of the ciliate C. acuminatus, which supposedly feeds on bacteria, algae, and other organic particles filtered out from the water by its host. The results of this study may apply to a wider spectrum of similar commensal associations in fresh waters.

The Evolutionary Ecology of Biotic Association in a Megadiverse Bivalve Superfamily: Sponsorship Required for Permanent Residency in Sediment

BackgroundMarine lineage diversification is shaped by the interaction of biotic and abiotic factors but our understanding of their relative roles is underdeveloped. The megadiverse bivalve superfamily Galeommatoidea represents a promising study system to address this issue. It is composed of small-bodied clams that are either free-living or have commensal associations with invertebrate hosts. To test if the evolution of this lifestyle dichotomy is correlated with specific ecologies, we have performed a statistical analysis on the lifestyle and habitat preference of 121 species based on 90 source documents.Methodology/Principal FindingsGaleommatoidea has significant diversity in the two primary benthic habitats: hard- and soft-bottoms. Hard-bottom dwellers are overwhelmingly free-living, typically hidden within crevices of rocks/coral heads/encrusting epifauna. In contrast, species in soft-bottom habitats are almost exclusively infaunal commensals. These infaunal biotic associations may involve direct attachment to a host, or clustering around its tube/burrow, but all commensals locate within the oxygenated sediment envelope produced by the host’s bioturbation.Conclusions/SignificanceThe formation of commensal associations by galeommatoidean clams is robustly correlated with an abiotic environmental setting: living in sediments (). Sediment-dwelling bivalves are exposed to intense predation pressure that drops markedly with depth of burial. Commensal galeommatoideans routinely attain depth refuges many times their body lengths, independent of siphonal investment, by virtue of their host’s burrowing and bioturbation. In effect, they use their much larger hosts as giant auto-irrigating siphon substitutes. The evolution of biotic associations with infaunal bioturbating hosts may have been a prerequisite for the diversification of Galeommatoidea in sediments and has likely been a key factor in the success of this exceptionally diverse bivalve superfamily.

Notes on the Association of Lissocarcinus polybiodes Adams and White, 1848 (Portunidae, Caphyrinae), with Sea Star Luidia Maculata Muller and Troschel, 1842

A portunid swimmer crab Lissocarcinus polybiodes Adams and White, 1848, which is usually free living or associated with hard corals (Stephenson, 1972), is shown to have commensal association with a sea star Luidia maculata MuUer and Troschel, 1842, is reported for the first time. Significantly, this is the second only report of this species from the Indian waters (Chennai Coast) after Alcock's (1899) description of specimens from Malabar, Orissa, Ganjam, Malabar and Andamans.

Phoresy and commensalism of Chironomidae larvae (Insecta: Diptera) in the state of Rio de Janeiro, Brazil

Chironomid larvae are frequently found living in phoretic or commensal association with aquatic animals in all regions of the world. In Brazil, new records have been available in the literature in the last years mainly for the state of São Paulo. In collects performed in several streams and rivers in the state of Rio de Janeiro and bordering areas, chironomid larvae were found living in association with Corydalidae (Megaloptera); Perlidae (Plecoptera); Leptophlebiidae (Ephemeroptera); Aeshnidae and Libellulidae (Odonata); Sericostomatidae (Trichoptera); Elmidae (Coleoptera) and catfishes of the families Trichomicteridae and Loricariidae (Pisces). These new records are presented in the present study.

Correction for Hughes et al., Chemical sensing in mammalian host-bacterial commensal associations

Correction for Hughes et al., Chemical sensing in mammalian host-bacterial commensal associations

Chemical sensing in mammalian host-bacterial commensal associations.

The mammalian gastrointestinal (GI) tract is colonized by a complex consortium of bacterial species. Bacteria engage in chemical signaling to coordinate population-wide behavior. However, it is unclear if chemical sensing plays a role in establishing mammalian host-bacterial commensal relationships. Enterohemorrhagic Escherichia coli (EHEC) is a deadly human pathogen but is a member of the GI flora in cattle, its main reservoir. EHEC harbors SdiA, a regulator that senses acyl-homoserine lactones (AHLs) produced by other bacteria. Here, we show that SdiA is necessary for EHEC colonization of cattle and that AHLs are prominent within the bovine rumen but absent in other areas of the GI tract. We also assessed the rumen metagenome of heifers, and we show that it is dominated by Clostridia and/or Bacilli but also harbors Bacteroidetes. Of note, some members of the Bacteroidetes phyla have been previously reported to produce AHLs. SdiA-AHL chemical signaling aids EHEC in gauging these GI environments, and promotes adaptation to a commensal lifestyle. We show that chemical sensing in the mammalian GI tract determines the niche specificity for colonization by a commensal bacterium of its natural animal reservoir. Chemical sensing may be a general mechanism used by commensal bacteria to sense and adapt to their mammalian hosts. Additionally, because EHEC is largely prevalent in cattle herds, interference with SdiA-mediated cattle colonization is an exciting alternative to diminish contamination of meat products and cross-contamination of produce crops because of cattle shedding of this human pathogen.

Commensalism Between Guiana Dolphins Sotalia guianensis and Sea Birds in the North Bay of Santa Catarina, Southern Brazil

Commensal associations between Guiana dolphins Sotalia guianensis and sea birds, Larus dominicanus, Sula leucogaster, Sterna sp. and Fregata magnificens have been frequently observed during the feeding behavior of the dol- phins in the North Bay of Santa Catarina, (26°00'-28°25'S, 48°30'-48°49'W), Southern Brazil. Boat and land surveys were performed, using focal group sampling method, in blocks of five minutes. In 81 surveys, between 1993 to 1997, as- sociations with birds were observed in 67% of the days (n= 54 days). The most representative years were 1993 (63.16%) and 1994 (73.68%), with a total frequency of 62.72%. In 1995, less associations were registered, only 8.5% of the total. In the following years associations were registered more frequently (16.13% in 1996 and 12.64% in 1997), but with lower intensity and numbers than the early years. The frequency of occurrence of the bird species also varied each year. Sterna sp. showed the highest time of occurrence in observed association (1587 minutes, 33.32% of the total time observed) and the highest frequency days in associations (n = 46, 85.18% of the total (= 54)). The second most representative bird spe- cies was F. magnificens with 1218 minutes of associations, almost 26% of the total, and observed in 40 days (74.07%of the total). S. leucogaster appeared with 951 minutes in association (19.97%) and it was observed in 29 (53.70%) of the 54 total days of associations registered. L. dominicanus showed the smaller time of occurrence, 925 minutes (19.42%) and it was registered in 29 days (53.7%) of associations, mainly in the austral winter. These associations occurs principally when the dolphins are executing coordinated feeding strategies, railing the fishes in big groups, making easy the obtain- ment of food to the birds, that is characterize this relation like commensalism.

Marine Chemical Ecology: Chemical Signals and Cues Structure Marine Populations, Communities, and Ecosystems

Chemical cues constitute much of the language of life in the sea. Our understanding of biotic interactions and their effects on marine ecosystems will advance more rapidly if this language is studied and understood. Here, I review how chemical cues regulate critical aspects of the behavior of marine organisms from bacteria to phytoplankton to benthic invertebrates and water column fishes. These chemically mediated interactions strongly affect population structure, community organization, and ecosystem function. Chemical cues determine foraging strategies, feeding choices, commensal associations, selection of mates and habitats, competitive interactions, and transfer of energy and nutrients within and among ecosystems. In numerous cases, the indirect effects of chemical signals on behavior have as much or more effect on community structure and function as the direct effects of consumers and pathogens. Chemical cues are critical for understanding marine systems, but their omnipresence and impact are inadequately recognized.

Two new interspecific associations of the hairy blenny Labrisomus nuchipinnis (Teleostei: Labrisomidae) in the South Atlantic

INTRODUCTION Interspecific associations are common features of complex environments such as coral reefs. Within coral reef communities, cleaning association and following behaviour are two of the most reported examples of interspecific associations (Grutter, 1999; Silvano, 2001; Feitoza et al., 2002; Soares & Barreiros, 2003). Cleaning association is a mutualistic symbiotic relationship that benefits both parties (Losey, 1971, 1987), whereas following behaviour is usually considered a commensal association in which one species benefits and the other is unharmed (Strand, 1988; Soares & Barreiros, 2003). In cleaning associations, a microcarnivore or opportunistic species (‘cleaner’) feeds on ectoparasites, mucus, algae and diseased tissue it removes from the body of a ‘client’ species (Losey, 1987; Grutter, 1999; Becker & Grutter, 2004; Sazima et al., 2004). In following behaviour, the ‘follower’, usually a generalist, opportunistic predator, follows a ‘nuclear’ species and feeds on the prey items not targeted or dispersed during the foraging activities of the latter (Strand, 1988; Soares & Barreiros, 2003; Sazima et al., 2006). In this paper, associations of the hairy blenny Labrisomus nuchipinnis (Quoy & Gaimard, 1824) are described for the first time based on observations made on the coast of Brazil, South Atlantic.

Freshwater shrimp–sponge association from an ancient lake

Shrimp-sponge associations occur frequently in marine ecosystems, serving as model systems for the evolution of eusociality. Here, we describe the first known instance of such association in freshwater from an ancient lake in Indonesia. The shrimp Caridina spongicola forms an exclusive and probably commensal association with a yet undescribed spongillinid sponge. Phylogenetic and ecological data suggest a comparatively recent origin of both taxa. Climatic fluctuations may have facilitated speciation and occasional hybridization of the shrimp species, which is derived from a rock-dwelling ancestor. Their extremely localized occurrence in an increasingly disturbed area makes both taxa a conservation priority.

Lessons from meningococcal carriage studies

Neisseria meningitidis, an obligate commensal of humans, normally colonizes the mucosa of the upper respiratory tract without affecting the host, a phenomenon known as carriage. In Europe, as much as 35% of young adults are carriers at a given time. Recent studies using molecular methods for clone identification have demonstrated the extensive genetic diversity of the strains isolated from carriers, in comparison with a limited number of hypervirulent strains associated with invasive disease. Published studies and new data generated through the framework of the EU-MenNet clearly indicated significant differences in pathogenicity between meningococcal clones and in the distribution of multilocus sequence types among isolates from asymptomatic carriers among European countries; simultaneous carriage of more than one meningococcal strain in the throat is rare, but occasionally occurs; and the commensal association of particular clones with a host is a long-term relationship, often lasting several months. Further investigations of the carrier state are warranted to improve our understanding of the epidemiology and pathogenesis of meningococcal disease, as well as to support the introduction and to measure the impact of mass vaccination.

When David and Goliath share a home: Compound nesting of Pyramica and Platythyrea ants

We documented a commensal association between two phylogenetically distant ant subfamilies (Ponerinae and Myrmicinae). The host (Platythyrea conradti) and its tiny guest (Pyramica maynei) nest in the same hollow branches in West African forests. Brood chambers are adjacent but separate, and the guest scavenges on prey remains of the host, which may benefit from improved nest hygiene. Two mated dealate queens of Pyramica were collected in one small Platythyrea nest, suggesting that they can hunt (non-claustral foundation) in the safe environment provided. An experiment showed that the guest can survive alone and was able to hunt collembolans.

New Methods for Medicinal Chemistry - Universal Gene Cloning and Expression Systems for Production of Marine Bioactive Metabolites

Natural products from symbiotic or commensal associations between marine invertebrate and microbial organisms show exceptional promise as pharmaceuticals in many therapeutic areas. An economic and sustainable global market supply due to difficulty of synthesis is cited as the main obstacle for exploitation of these otherwise exciting marine bioactive compounds. Different strategies have been evoked to overcome this impediment as long-term harvesting of wild stocks from the environment is considered unsound, and other modes of production based on biosynthesis, such as aquaculture, have not yet been proven as reliable. One option is to clone the genes encoding the biosynthetic expression of a lead metabolite into a surrogate host suitable for industrial-scale fermentation. To facilitate this goal we are developing a universal system to clone and express genes responsible for biosynthesis of natural products from both eukaryotic and prokaryotic partners of marine symbioses. The ability to harness the complete meta-transcriptome of entire biosynthetic pathways is particularly valuable where the biogenesis of a target natural product occurring within a complex symbiotic association is unclear.