Hermit Crab Clibanarius Vittatus Research Articles

Effects of tributyltin exposure in hermit crabs: Clibanarius vittatus as a model

Tributyltin (TBT) contamination affects the reproductive system of many species of invertebrates worldwide. The present study was designed to evaluate the effects of exposure to TBT pollution on the reproduction of the hermit crab Clibanarius vittatus. An orthogonal experiment was designed with two treatments: contamination (with or without TBT in the food) and crab sex (males and females). The animals were reared in the laboratory for nine months, and macroscopic and histological analyses of reproductive organs were carried out after the end of the experiment. Tributyltin was recorded in exposed crabs, but no morphological alterations were detected in the gonads of males, regardless of whether they were exposed to TBT. In contrast, females exposed to TBT displayed disorganization and atrophy of their ovaries, thus directly affecting reproduction in this hermit crab species. This effect observed in female hermit crabs may harm populations located in harbor regions, where TBT concentration is high, even after the worldwide TBT ban.

Hemolymph ion regulation and kinetic characteristics of the gill (Na+, K+)-ATPase in the hermit crab Clibanarius vittatus (Decapoda, Anomura) acclimated to high salinity

We examine hemolymph ion regulation and the kinetic properties of a gill microsomal (Na(+), K(+))-ATPase from the intertidal hermit crab, Clibanarius vittatus, acclimated to 45‰ salinity for 10 days. Hemolymph osmolality is hypo-regulated (1102.5 ± 22.1 mOsm kg(-1) H(2)O) at 45‰ but elevated compared to fresh-caught crabs (801.0 ± 40.1 mOsm kg(-1) H(2)O). Hemolymph [Na(+)] (323.0 ± 2.5 mmol L(-1)) and [Mg(2+)] (34.6 ± 1.0 mmol L(-1)) are hypo-regulated while [Ca(2+)] (22.5 ± 0.7 mmol L(-1)) is hyper-regulated; [K(+)] is hyper-regulated in fresh-caught crabs (17.4 ± 0.5 mmol L(-1)) but hypo-regulated (6.2 ± 0.7 mmol L(-1)) at 45‰. Protein expression patterns are altered in the 45‰-acclimated crabs, although Western blot analyses reveal just a single immunoreactive band, suggesting a single (Na(+), K(+))-ATPase α-subunit isoform, distributed in different density membrane fractions. A high-affinity (Vm=46.5 ± 3.5 Umg(-1); K(0.5)=7.07 ± 0.01 μmol L(-1)) and a low-affinity ATP binding site (Vm=108.1 ± 2.5 U mg(-1); K(0.5)=0.11 ± 0.3 mmol L(-1)), both obeying cooperative kinetics, were disclosed. Modulation of (Na(+), K(+))-ATPase activity by Mg(2+), K(+) and NH(4)(+) also exhibits site-site interactions, but modulation by Na(+) shows Michaelis-Menten kinetics. (Na(+), K(+))-ATPase activity is synergistically stimulated up to 45% by NH(4)(+) plus K(+). Enzyme catalytic efficiency for variable [K(+)] and fixed [NH(4)(+)] is 10-fold greater than for variable [NH(4)(+)] and fixed [K(+)]. Ouabain inhibited ≈80% of total ATPase activity (K(I)=464.7 ± 23.2 μmol L(-1)), suggesting that ATPases other than (Na(+), K(+))-ATPase are present. While (Na(+), K(+))-ATPase activities are similar in fresh-caught (around 142 nmol Pi min(-1)mg(-1)) and 45‰-acclimated crabs (around 154 nmol Pi min(-1)mg(-1)), ATP affinity decreases 110-fold and Na(+) and K(+) affinities increase 2-3-fold in 45‰-acclimated crabs.

Tributyltin in crustacean tissues: analytical performance and validation of method

The hermit crab Clibanarius vittatus is a typical organism from intertidal regions being considered as a good bioindicator of tributyltin presence at these environments. Thus this study presents the analytical performance and validation method for TBT quantification in tissues of C. vittatus by gas chromatography with pulsed flame photometric detector (GC-PFPD) after extraction with an apolar solvent (toluene) and Grignard derivatization. The limits of detection of the method (LOD) were 2.0 and 2.8 ng g-1 for TBT and DBT (dibutyltin), respectively, and its limits of quantification (LOQ) were 6.6 and 8.9 ng g-1 for TBT and DBT, respectively. The method was applied to samples from Santos Estuary, São Paulo State, Brazil. TBT and DBT concentrations ranged from 26.7 to 175.0 ng g-1 and from 46.2 to 156.0 ng g-1, respectively. These concentrations are worrisome since toxic effects (such as endocrine disruption) have been reported for other organisms even under lower levels of registred at this study.

Characterization of the occupied shells by the hermit crab Clibanarius vittatus (Decapoda, Diogenidae) at Baixio Mirim tideflat, Guaratuba Bay, southern Brazil

A characterization of the occupied shells by the hermit crab Clibanarius vittatus was carried out. Hermit crabs were collected in the intertidal zone, during the low spring tide monthly from April 2005 to March 2006. They were sexed and their cephalothoracic shield length (CL) was measured. Shells were identified, dried, weighed and the aperture length (AL) and width (AW) were measured. 1187 crabs were collected (949 males, 216 females and 22 intersexes), which occupied 12 species of gastropod shells. Stramonita haemastoma, Olivancillaria urceus and Dorsanum moniliferum made up 96.55% of the total shell species. Male hermit crabs attained significantly larger sizes than females; therefore, males occupied a wider spectrum of shells in size and weight. A stronger correlation ratio was obtained between CL and AW of S. haemastoma. Last whorl with a rounded shape and a spacious inner area is a common feature of all shell species most frequently occupied by this hermit crab where it occurs. The successful establishment of C. vittatus at Baixio Mirim is mainly due to the appropriately shaped and wide range of size of S. haemastoma shells that were most often occupied by the hermit crabs of the studied population.

Size Relationships and Aggressive Behavior in the Hermit Crab Clibanarius vittatus

Zusammenfassung In Kampfversuchen mit dem Einsiedlerkrebs Clibanarius vittatus wurde die Korpergrose der Kampfer mit dem Ausgang des Kampfes verglichen. Mit dem Grosenunterschied zwischen beiden wuchs die Wahrscheinlichkeit, das die Partner einander “ubersahen”, das das grosere Tier siegte, und das das kleinere sich zuruckzog, ehe das grosere drohte; zugleich sinkt die Wahrscheinlichkeit, das das grosere Tier droht oder auf ein Drohen des kleineren reagiert. Es lies sich zeigen, das grosere Tiere angriffslustiger sind. Sehr wahrscheinlich reagieren die Tiere auf die absolute Rivalengrose.

A comparative study of population traits between two South American populations of the striped-legged hermit crab Clibanarius vittatus

The striped-legged hermit crab Clibanarius vittatus, with a geographical distribution covering a wide range of latitudes in the western Atlantic, was selected for a comparative study on population features between two different areas of the Brazilian coast that are separated by approximately 3000 km. The two populations were sampled concurrently for nine months. The populations in northern and southeastern Brazil showed different profiles in terms of size of specimens, sex ratio, and shell occupation. The observed plasticity of these life-cycle traits of C. vittatus in relation to local environmental conditions is discussed.

Distribuição temporal do ermitão Clibanarius vittatus (Anomura, Diogenidae) no litoral do Paraná

Um estudo sobre a flutuação temporal da estrutura populacional do ermitão Clibanarius vittatus (Bosc, 1802) foi realizado no Baixio Mirim, Baía de Guaratuba, Estado do Paraná, Brasil (25°52'S, 48°36'W). Clibanarius vittatus é uma espécie largamente estudada, entretanto estudos da biologia populacional desta em diferentes regiões são escassos. Coletas mensais foram realizadas na zona entremarés, de abril/2005 a março/2006. Foram obtidos 1187 ermitões, dos quais, 949 machos, 22 indivíduos intersexo, 204 fêmeas não ovígeras e 12 fêmeas ovígeras. O comprimento do escudo cefalotorácico (CEC) foi medido e agrupado em 10 classes de tamanho. Machos ocorreram em 10 classes de CEC, enquanto fêmeas e intersexos em apenas seis. A razão de sexos total e mensal foi a favor dos machos. Todas as categorias demográficas estiveram presentes o ano inteiro, com exceção dos intersexos e das fêmeas ovígeras. Estas foram pouco frequentes e ocorreram do final da primavera até o outono, e em agosto de 2005. O período reprodutivo foi considerado contínuo-sazonal, com maior intensidade nos meses mais quentes. A razão de sexos nesta população, que é diferente das demais estudadas, corrobora a teoria de migração proposta para esta espécie. O presente estudo constitui o primeiro registro do período reprodutivo desta espécie em águas rasas de clima subtropical quente.

Population biology and reproduction of the hermit crab Clibanarius vittatus (Decapoda: Anomura) in an estuarine region of southern Brazil

The population dynamics and reproduction of the hermit crab Clibanarius vittatus were evaluated on Pescadores Beach, located on the estuarine channel of São Vicente (São Paulo), Brazil. The hermit crabs were captured by hand during low tide, from May 2001 to April 2003. A total of 2554 hermit crabs were captured, of which 701 were males, 1741 non-ovigerous females, 48 ovigerous females and 64 intersex individuals. The size–frequency distribution of the males was represented by a platykurtic bell-shaped curve, which differed from the leptokurtic bell-shaped curve of the females. The smaller and intermediate classes were composed mainly of females (modal size 6.5–7.5 mm carapace shield length (CSL)), and the larger classes only by males (modal size 9.5–10.5 mm CSL). The overall sex-ratio was skewed toward females (0.39:1/M:F), differing significantly from the expected 1:1. A seasonal reproductive pattern was recorded for C. vittatus in this location, with more intensive reproductive activity in the warmer months. The absence of juveniles suggests that their recruitment area is different than the area inhabited by adults, possibly another area with more protection and specialized or different resources for young.

Growth of the hermit crab Clibanarius vittatus (Bosc, 1802) (Crustacea, Anomura, Diogenidae) at São Vicente, São Paulo, Brazil

The present study analyzed the growth of males and females of the hermit crab Clibanarius vittatus (Bosc, 1802), at São Vicente, São Paulo, Brazil. Monthly collections were made from May/2001 through April/2003, at the Pescadores Beach in São Vicente. The 2,501 crabs caught were identified and sexed and the carapace shield length (CSL) was measured. For the seasonal growth study, the population was divided into 5mm size classes (CSL) and analyzed by the Bertalanffy method, with the aid of the program Fisat II. The mean sizes of the 703 males and 1,798 females were 8.94±1.80 and 6.61±1.13 mm, respectively. A seasonal growth pattern was observed, with males reaching an asymptotic size (14.92 mm) larger than that of females (13.85 mm). Males began the growth process approximately five months before the females. This growth pattern probably helped to reduce intraspecific competition for the shells, because the males reached larger size and made the smaller shells available to the females.

Shell utilization pattern of the hermit crab Clibanarius vittatus (Crustacea, Anomura) in an estuary at São Vicente, State of São Paulo, Brazil

We evaluated the gastropod shell utilization pattern of the hermit crab Clibanarius vittatus (Bosc, 1802) at Pescadores Beach in São Vicente, State of São Paulo, Brazil. Specimens were collected monthly from May 2001 through April 2003, in the intertidal zone at low tide. The crabs were weighed and their carapace shield length measured. All gastropod shells were identified and had their shell biometric parameters (total length and aperture length) measured (mm) and weighed (g). A total of 2,344 hermit crabs (644 males, 1,594 females, 45 ovigerous females and 61 individuals in intersex), using 13 species of gastropod shells, were collected. Stramonita haemastoma (Linnaeus, 1767), Cymatium parthenopeum (Von Salis, 1793) and Achatina fulica (Bowdich, 1822) comprised over 98% of all the shells. Male and intersex crabs were significantly larger than the females. This size difference strongly influenced the shell utilization pattern, principally in A. fulica, which has the largest shell size, that was only used by males and intersexual individuals of C. vittatus. Cymatium parthenopeum was the only shell species that showed a high determinant coefficient in all the biometric correlations evaluated. The high abundance of S. haemastoma shells and a strong correlation between crab size and shell aperture length established by a significant determination coefficient, indicated that C. vittatus uses this species as the principal resource for shell occupation at Pescadores Beach.

Utilization of shells of the snail Achatina fulica Bowdich, 1822 (Mollusca, Gastropoda) by the hermit crab Clibanarius vittatus (Bosc, 1802) (Decapoda, Anomura) in the São Vicente Estuary, São Paulo, Brazil

Hermit crabs depend on mollusc shells for housing. In this study, an unusual resource is reported for a hermit crab that usually inhabits marine gastropod shells. During a field study conducted from May 2001 to April 2003 in an estuarine area in Sao Vicente, state of Sao Paulo, Brazil, 21 individuals of Clibanarius vittatus (Bosc, 1802) were found inhabiting the shells of the terrestrial gastropod Achatina fulica Bowdich, 1822. A. fulica occurs in nearshore grass patches, where occasional contact with sea water kills them, and their shells then become available to the hermit crabs.

Effects of food and shell cues on mating in the hermit crab Clibanarius vittatus

In hermit crabs, Clibanarius vittatus, activities associated with foraging for food and searching for a different gastropod shell are incompatible with mating activities. We hypothesized that due to the short mating season that mating would have priority over feeding or shell seeking. We compared the mating activities of groups of crabs in the absence of food and shell cues to mating activities of groups of crabs presented with food cues, shell cues, or a combination of food and shell cues. We measured the number of minutes of precopulatory behaviors executed and the number of pairs formed in these groups during 60 minutes periods.Comparison of mating activity in the presence and absence of shell availability cues supported our hypothesis. Shell availability cues had no effect on the number of pairs formed or the number of minutes of precopulatory behaviors. However, responses to food cues did not support the hypothesis. Food cues from high quality food very significantly decreased both the number of pairs formed and the number of minutes of precopulatory behavior executed. This was true for both food cues alone or in combination with shell-availability cues. The dominance of food-related activities over reproductive activities was surprising given the short mating season of C. vittatus at the latitude tested.

Predation–Reproduction Conflict Resolution in the Hermit Crab, Clibanarius vittatus

AbstractActivities associated with courtship are often in conflict with avoiding elevated predation risk. In polygamous species with temporally restricted mating seasons, males should be less responsive to interruption of courtship by detection of elevated predation risk compared to females. We tested this prediction with the hermit crab Clibanarius vittatus. Courting males continued to execute pre‐copulatory behavior patterns when exposed to predator odors. However, in the presence of predator odors, fewer pairs were established. Exposing previously paired males and females to predator cues showed that males were unaffected in their motivation to form pairs, whereas females were no longer attractive to males following exposure to predator cues.

Responses of mud snails and periwinkles to environmental odors and disaccharide mimics of fish odor

Estuarine snails, periwinkles (Littoraria irorata), and mud snails (Ilyanassa obsoleta) were tested for behavioral responses to aqueous extracts of tissue macerates, odors of living intact organisms, and to disaccharides derived from heparin. Extracts included salt-marsh cordgrass (Spartina alterniflora), pink shrimp (Penaeus duorarum), crushed periwinkles, and crushed mud snails. Odors included live periwinkles, mud snails, stone crab (Menippe mercenaria), striped hermit crab (Clibanarius vittatus), tulip snail (Fasciolaria hunteria), and mummichog (Fundulus heteroclitus). Responses were determined upon contact by snails of a ring of solution in the bottom of an otherwise dry bowl and by presenting snails in seawater with 25 μl of solution on a cotton swab. In each test, the response of 30 individuals was determined. Behaviors were recorded as fed, alarm, and no response. The strongest alarm response (>80% of all snails tested) in both snails was elicited by crushed mud snails. The strongest feeding response was to shrimp and periwinkle extract for mud snails (>70%), and salt-marsh cordgrass extract attracted periwinkles. High percentages of mud snails and periwinkles fled in response to the odors of intact snail predators, stone crabs, tulip snails, and mummichogs. Mud snails and periwinkles did not flee in response to nonpredator odors, including each other's odor, as well as that of hermit crabs, shrimp, and marsh cordgrass. Heparin disaccharides were tested because other studies reported that biological activity of predatory fish odor is due to similar disaccharides originating from fish mucus. Mud snail responses to disaccharides indicate that they respond to the same kinds of molecules as crustacean larvae and that the modified amine on the disaccharide is essential for activity. The Q-tip assay is appropriate for bioassay-directed purification of alarm signals originating in fish body odor.

Temporal development of salt marsh value for nekton and epifauna: utilization of dredged material marshes in Galveston Bay, Texas, USA.

Densities of nekton and other fauna were measured inthree created salt marshes to examine habitatdevelopment rate. All three marshes were located onPelican Spit in Galveston Bay, Texas, USA and werecreated on dredged material from the Gulf IntracoastalWaterway. The youngest marsh was planted on 1-mcenters in July of 1992. At the time sampling wasinitiated in fall 1992, the marshes were 9, 5, andless than 1 year in age; sampling continued in thefall and spring through spring 1994. Animaldensities were measured within the vegetation at twoelevations using an enclosure sampler. In the fall of1992, 4 months following the planting of the 92Marsh,densities of most marsh organisms were lower in thismarsh compared with the older two marshes. Significantly lower densities were observed fordominant crustaceans (including three species of grassshrimps, two species of commercially-important penaeidshrimps, thinstripe hermit crabs Clibanarius vittatus,and juvenile blue crabs Callinectes sapidus), adominant fish (Gobionellus boleosoma), and thedominant mollusc (Littoraria irrorata). By the fallof 1993, however, densities of most nekton specieswere similar among the three created salt marshes. Incontrast, reduced densities of less mobile epifauna(C. vittatusand L. irrorata) persisted in the 92Marshthroughout the 2 years of sampling. The patterns ofnekton utilization exhibited in these marshes suggestthat the 92Marsh reached its maximum habitat supportfunction for these animals in less than 1 year. Comparisons of the older marshes with natural marshesin the bay system, however, suggest that all three ofthese created marshes are functioning at lower levelsthan natural marshes in terms of supporting productionof commercially important fishery species such aspenaeid shrimps and C. sapidus.

Genes for asymmetry easily overruled

The hermit crab Clibanarius vittatus inhabits empty gastropod shells and is highly asymmetric. I have found that this asymmetry does not depend on initial possession of a shell, but can be lost within a few moults in the absence of shells, suggesting that the morphology has a genetic component but is environmentally regulated. The loss of dependence on shells has been implicated in the evolution of the nearly symmetrical, fully armoured king crabs and coconut crabs from hermit crab ancestors1,2. The first steps of such a transformation may thus have been much easier than previously thought3,4.

Assessments during shell exchanges by the hermit crab Clibanarius vittatus: the complete negotiator

The behaviour of the hermit crab Clibanarius vittatuswas studied as it investigated shells prior to and during shell exchange interactions. Crabs behaved in a manner predicted by the negotiations model of resource exchange, that is, shells were primarily exchanged between crabs when both crabs benefited in shell fit from the exchange. During initial investigation of shells, crabs in poorly fitting shells selected shells that (1) were similar to the preferred shell size of the investigating crab and (2) that did not fit their current occupant well. In addition, the greater the shell deficit (deviation from that crab's preferred shell size) of the other crab, the more likely it was investigated by a crab in a poorly fitting shell. Considering three factors (initiator's preferred shell size, current shell deficit of the non-initiator and magnitude of gain possible for the non-initiator) explained 86% (multiple r=0.93) of the variance in shells rapped by initiating crabs. In those interactions that proceeded to rapping behaviour, the magnitude of gain in shell fit that the non-initiating crab would experience if a shell exchange occurred helped explain which shells were selected for rapping. The relative size of the two crabs was only important in the assessment and decisions process once rapping began, and the number of raps was inversely proportional to the relative size difference of the crabs.

Organisation of Hermit Crab Behaviour: Responses To Multiple Chemical Inputs

To characterize the organisation of behaviour, the responses to chemical inputs of individuals of the diogenid hermit crab Clibanarius vittatus were tested in the laboratory. Stimuli were introduced both singly and in combinations on three days (one, four, and seven days after the crabs were last fed). First, responses to single inputs were characterized: (a) odour of a predator elicited an increase in locomotion; (b) odour of food also elicited an increase in locomotion; (c) odour resulting from snail predation (a signal of availability of an empty shell) elicited brief grasps of the shells of other crabs and (d) the odour of conspecific blood elicited long grasps of shells. Individual crabs differed significantly in their tendencies to respond to chemical signals. Those responding strongly to one cue responded strongly to other cues. Those responding to one shell-related cue (snail odour) responded to the other such cue (conspecific blood) and individuals showing a stronger response to food odours the first day did so on subsequent days. Combinations of cues yielded examples of both summation of inputs (rate of locomotion when snail and predator odours were combined) and inhibition of the responses to one input by the detection of the second odour (brief grasps typical of the response to snail odour were eliminated by addition of predator odour). Responses to conspecific blood were unaffected by predator odour detection. Increasing levels of hunger resulted in increases in locomotion in response to some chemical signals (control, snail odour, and conspecific blood) and a decrease in the number of brief grasps elicited by snail odour. The combination of increased hunger level and multiple chemical inputs yielded patterns not predictable from the two-factor combinations. The rate of locomotion decreased over time for snail + predator odours together and for blood + predator odours together, whereas the single odours resulted in either an increase or no change over time. Food + predator odours together elicited an increase in both long grasps of shells and feeding movements over days without food. While most instances of summation or inhibition of responses seemed biologically reasonable, other multi-input responses observed were difficult to explain. Thus, it is difficult to make generalisations about the interactive effects of various inputs.

Behavioral plasticity in crustacea: why not more?

The extent of plasticity in the behavior of hermit crabs is reviewed. Data are presented demonstrating that in the hermit crab Calcinus tibicen, the diversity of experience with shell types affects the ease with which crabs enter novel shells. Hermit crabs that had more diverse experience with shell types made fewer mistakes and entered novel shells more quickly than individuals with less diverse experience. Examples of the limitations on the extent of plasticity are reviewed and some of the mechanisms which could lead to limitations are discussed. These mechanisms include (a) sensory capabilities, (b) morphological constraints, (c) limits on learning abilities, and (d) constraints by cognitive structure, i.e. the nature of the connections between categories of behavior. As an example of the latter, data are presented for the hermit crab Clibanarius vittatus showing that crabs that regularly detected blood of conspecifics (a presumed indicator of a high predation level) did not select different shells than controls not exposed to such input.

VISUAL ORIENTATION TO GASTROPOD SHELLS BY CHEMICALLY STIMULATED HERMIT CRABS, CLIBANARIUS VITTATUS (BOSC)

ABSTRACT Visually directed movements of the hermit crab Clibanarius vittatus (Bosc) toward 6 species of gastropod shells were studied in a circular arena with a white wall. The study tested the hypothesis that crabs visually discriminate between different species of shells. Only Investigating Crabs, those exhibiting chemically induced shell-investigation behavior, were tested. All trials were in the presence of chemical cues generated by freezing and thawing flesh from the gastropods Busycon carica or Polinices duplicatus. Directional orientation was absent when crabs were presented with the white background alone. Each shell was tested in different positions (e.g., anterior, posterior, upside-down, lateral). Crabs were attracted to shells in 9 of the 18 test conditions, with strongest attraction to Polinices duplicatus (posterior position) and Busycon contrarium (lateral position). Since attraction was not related to shell height, width, or surface area, it was concluded that crabs can discriminate between shells and were most attracted to shells that attain larger sizes. In a second experimental series, shells of B. contrarium or P. duplicatus were presented simultaneously in different positions. Crabs could distinguish between both species in different positions. When these 2 shell species were presented simultaneously, crabs were significantly attracted to P. duplicatus in the presence of the odor of either B. carica or P. dupticatus. Thus, these results support the hypothesis and further indicate that attraction to a shell involves a complex interaction of proprioreceptive input from the host shell, chemical cues indicating the availability of a new shell, and visual recognition of a particular shell species.