Dardanus Arrosor Research Articles

Different gene rearrangements of the genus Dardanus (Anomura: Diogenidae) and insights into the phylogeny of Paguroidea

Complete mitochondrial genomes (mitogenomes) can provide useful information for phylogenetic relationships, gene rearrangement, and molecular evolution. In this study, the complete mitogenomes of two hermit crabs, Dardanus arrosor and Dardanus aspersus, were sequenced for the first time and compared with other published mitogenomes of Paguroidea. Each of the two mitogenomes contains an entire set of 37 genes and a putative control region, but they display different gene arrangements. The different arrangements of the two mitogenomes might be the result of transposition, reversal, and tandem duplication/random loss events from the ancestral pancrustacean pattern. Genome sequence similarity analysis reveals the gene rearrangement in 15 Paguroidea mitogenomes. After synteny analysis between the 15 Paguroidea mitogenomes, an obvious rearranged region is found in D. aspersus mitogenome. Across the 13 protein-coding genes (PCGs) tested, COI has the least and ND6 has the largest genetic distances among the 15 hermit crabs, indicating varied evolution rates of PCGs. In addition, the dN/dS ratio analysis shows that all PCGs are evolving under purifying selection. The phylogenetic analyses based on both gene order and sequence data present the monophyly of three families (Paguridae, Coenobitidae, and Pylochelidae) and the paraphyly of the family Diogenidae. Meanwhile, the phylogenetic tree based on the nucleotide sequences of 13 PCGs shows that two Dardanus species formed a sister group with five Coenobitidae species. These findings help to better understand the gene rearrangement and phylogeny of Paguroidea, as well as provide new insights into the usefulness of mitochondrial gene order as a phylogenetic marker.

Invertebrate predation on egg masses of the European cuttlefish, Sepia officinalis: An experimental approach

The eggs of the European cuttlefish, Sepia officinalis, develop attached to the seafloor in shallow water habitats and possess a relatively thick black capsule that protects them from the surrounding environment. Since embryological development may take several months, eggs are vulnerable to a variety of threats present in shallow waters, including predation. This study investigates predation of S. officinalis eggs by benthic invertebrates. Twenty-eight invertebrate species from 6 different phyla and with diverse feeding habits were tested as potential predators under laboratory conditions. We also investigated how the feeding traits of these species are related to the mechanical ability to break the egg capsule and prey upon cuttlefish embryos. Species that fed on cuttlefish eggs were the sea snail Bolinus brandaris, the crab Cancer pagurus, the hermit crab Dardanus arrosor, the lobster Homarus gammarus, the invasive blue crab Callinectes sapidus, the shrimp Squilla mantis, the sea urchins Echinus melo, Cidaris sp. and Paracentrotus lividus and the starfish Astropecten aranciacus. It is of note that C. sapidus is a potential predatory crab, which raises the concern that this invasive species may constitute a novel threat for cuttlefish eggs as more populations become established in NE Atlantic waters. Of the biological traits examined, prey capture tools in the tested species best explained the experimental feeding results, suggesting that predation of S. officinalis eggs was determined generally by a mechanical factor and highlighting the importance of the protective egg capsule against predators. However, chemosensory factors are likely to be implicated as well. Thus, this work contributes to the understanding of the ecology of early life stages of cuttlefish and the factors that can affect offspring survival and subsequently impact the recruitment of this species.

The decapod fauna (Axiidea, Anomura, Brachyura) from the Late Pleistocene of Trumbacà, Reggio Calabria (Calabria, southern Italy).

We report a rich faunal assemblage from the Tyrrhenian (Late Pleistocene) of Trumbacà, located in the southern area of Reggio Calabria (Calabria, southern Italy). The only brachyuran reported to date from this locality is Ranilia constricta (A. Milne Edwards, 1880) by Vazzana (2008). The studied specimens have been assigned, as follows: ?Corallianassa sp., Dardanus arrosor (Herbst, 1796), Dardanus substriatus (A. Milne Edwards, 1861), Paguristes cf. P. syrtensis de Saint Laurent 1970, Anapagurus sp., Ranilia constricta (A. Milne Edwards, 1880), Ranina propinqua Ristori, 1891, Ebalia cf. E. deshayesi Lucas, 1846, Ilia nucleus (Linnaeus, 1758), Medorippe lanata (Linnaeus, 1767), Calappa granulata (Linnaeus, 1758), Pisa armata (Latreille, 1803), Derilambrus cf. D. angulifrons (Latreille, 1825), Atelecyclus undecimdentatus (Herbst, 1783), Carcinus sp., Pilumnus hirtellus (Linnaeus, 1761), and Xantho cf. X. incisus (Leach, 1814). The studied assemblage enlarges our knowledge on the evolution of the Mediterranean decapod faunas.

고리 주변해역 통발에서 채집된 십각류 종조성의 계절변동과 연간변동

The seasonal and interannual variation in the species composition and abundance of the decapod assemblage (shrimps, crabs, and hermit crabs) collected using pots in the coastal waters off Gori were studied between 2005 and 2008. During the study period, 49 decapod species belonging to 19 families were collected. The dominant species were Crangon hakodatei, Pandalus gracilis, Carcinoplax longimana, Charybdis bimaculata, Carcinoplax vestita, Diogenes edwardsii, and Dardanus arrosor. These seven species accounted for 95.46% of the total number of individuals collected. The number of species, number of individuals, biomass, and species diversity indices fluctuated with the seasons. The peak number and biomass of individuals occurred in July 2006. The number and biomass of individuals were higher in summer and lower in winter, and the diversity indices were lower in summer than in the other seasons. The abundance of dominant species showed some seasonal and interannual change; in particular, those of C. hakodatei and P. gracilis corresponded with the bottom water temperature.

The use of pleopods for shell water circulation and respiration by hermit crabs

The use of the pleopods was investigated in two species of Diogenid hermit crabs, Dardanus arrosor and D. calidus. A transparent glass shell was used to observe the movements of the pleopods in hermit crabs. The movements consisted of periodic, irregular beating, which generated an irregular flow of the water within the shell. A strong, regular beating movement was elicited when there was detritus or faeces in the shell, as was occupation of a new shell. Injection of water with a low oxygen concentration into the shell failed to induce any variation in the pleopod beating frequency (PBF), while the injection of water with a high CO2 concentration induced a sudden PBF increase. When pH was varied and CO2 concentration held at normal atmospheric level, there was a change in PBF. However, CO2 variation alone, at constant pH, did not trigger any visible reaction. This suggests that there is a receptor for pH, which acts independently of the CO2 concentration. The function of males hermit crabs pleopods has always been obscure. However, at least in Dardanus, they are actively involved in water circulation within the shell for shell-cleaning and probably for ventilation.

Hermit crab biocoenoses: a worldwide review of the diversity and natural history of hermit crab associates

The symbiotic associates of hermit crabs (excluding parasites and flora) are reviewed worldwide. The review includes species found on the shells occupied by hermit crabs (epibiotic species), species boring into these shells (endolithic species), species living within the lumen of the shell (either free-living or attached to the shell), species attached to the hermit crabs themselves, and hypersymbionts. In total over 550 invertebrates, from 16 phyla are found associated with over 180 species of hermit crabs. Among these associates, 114 appear to be obligate commensals of hermit crabs, 215 are facultative commensals, and 232 are incidental associates. The taxa exhibiting the highest number of associates are arthropods (126), polychaetes (105), and cnidarians (100). The communities of species associated with Dardanus arrosor, Paguristes eremita, Pagurus bernhardus, Pagurus cuanensis, and Pagurus longicarpus are the best studied and harbor the most diverse assemblages of species. While trends in biodiversity of hermit crab assemblages do not follow predicted patterns (e.g., hermit crabs within the Indo-West Pacific do not harbor more species than those from temperate regions), this is suggested to reflect a lack of sampling rather than a true representation of the number of associates. Hermit crabs date to at least the Cretaceous and provided a niche for a number of groups (e.g., hydractinians, bryozoans, polydorids), which were already associates of living gastropods. Apparently hermit crab shells initially supplied a substrate for settlement and then these symbiotic relationships were reinforced by enhanced feeding of symbionts through the activity of the hosts. Through their use and recycling of gastropods shells, hermit crabs are important allogenic ecosystem engineers in marine habitats from the intertidal to the deep sea. Hermit crabs benefit from some symbionts, particularly cnidarians and bryozoans, through extension of shell apertures (alleviating need to switch into new shells) and by providing protection from predators. However, hermit crabs are also negatively impacted (e.g., decreased reproductive success, increased predation) by some symbionts and a review of egg predators is provided. Thus, the symbiotic relationships between hermit crabs and many associates are difficult to characterize and often exhibit temporal changes depending on environmental and biological factors. Research on the biology of these symbionts and the costs/benefits of their associations with hermit crabs are analyzed. While some associates (e.g., Hydractinia spp.) have been studied in considerable detail, for most associations little is known in terms of the impacts of symbionts on hosts, and future experimental studies on the multitude of relationships are suggested.

Ecology of a parasitic barnacle, Koleolepas avis: relationship to the hosts, distribution, left–right asymmetry and reproduction

The pedunculate barnacle Koleolepas avis is a symbiont of the sea anemone Calliactis japonica, which lives on gastropod shells carried by large hermit crabs, usually Dardanus arrosor. Relationships with the host sea anemone, distribution on the gastropod shell, left–right asymmetry and reproduction of the barnacle were investigated. A larger number of barnacles occurred on shells with greater ‘cylindroid dimensions’ of sea anemones. Distribution of barnacles on shells was not random: assuming the in situ position of the shell carried by the hermit crab (∼45° inclination), there were more barnacles along the lower part of the anemone disk than the upper part. Large barnacles lie on either the left or right sides of their capitula, and those lying on the left side (Type L individuals) tended to occur along the left side of the host, and those on the right side (Type R) along the right side. Barnacles [ges ]0·016 g in wet weight had egg masses, and there was a positive relationship between body weight and number of eggs. Koleolepas avis has both hermaphrodites and dwarf (complementary) males attached to them. Large hermaphrodites tended to have larger dwarf males than smaller hermaphrodites.

Cropping of sea anemone tentacles by a symbiotic barnacle

As sessile animals, barnacles (Cirripedia: Thoracica) are generally suspension feeders, extending their cirri into the surrounding water to collect food particles (1). Although it has been suggested that some symbiotic barnacles obtain nutrients directly from their hosts, either by absorbing body fluids (2-4) or by rasping the host's tissue (4-6), most of these cases are inferred from their morphology. Direct evidence, such as gut content analysis, has been limited (for an exception, see ref. 5), and no actual feeding on their hosts has been observed. Koleolepas avis (Hiro, 1931) is a pedunculate barnacle symbiotic with the sea anemone Calliactis japonica, which lives on gastropod shells occupied by large hermit crabs (7), mainly Dardanus arrosor. Symbiotic relationships between various hermit crabs and sea anemones have been well documented (8), but the relationship between the barnacle and its host sea anemone has been virtually unknown. From February to April 1996, we collected living individuals of K. avis from lobster nets landed at Minabe Fishery Port, southwestern Japan (33{deg} 44' N, 135{deg} 20' E). On the basis of behavioral observations in the laboratory and analyses offecalpellets and gut contents, we concluded that this barnacle feeds actively on its host's tentacles.

Desenvolvimento larval de Dardanus insignis (Saussure) (Crustacea, Decapoda, Diogenidae), em laboratório

The developmental stages of Dardanus insignis (Saussure, 1858) from first through eighth zoea and megalopa are described and illuslraled. The experiments were carried out involving 100 larvae, obtained from ovigerous females collected on the north littoral of the state of Sao Paulo, Brazil. The larvae were kept in individual containers, with water of 34‰ salinity and fed with freshly hatched nauplii of Artemia; room temperature was maintained at 25±1oC. The larval characters of this species are compared with Dardanus arrosor (Herbst, 1796). the only species of the genus that has also heen reared in laboratory.

Decapod crab zoeae as food for rearing cephalopod paralarvae

A simple method of providing a regular supply of live food for the experimental culture of paralarval cephalopods is described. The primary food source utilized was hatched zoeae of large laboratory populations of the hermit crab, Pagurus prideaux. Zoeal size, swimming behaviour, and distribution in the water column make these zoeae a suitable live prey for rearing early post-hatching planktonic stages of cephalopods and probably other marine zooplanktivores. Ovigerous P. prideaux females were collected from the sea throughout the year at depths between 10 and 90 m in the NW Mediterranean and maintained at densities of up to 500 specimens · m −2. One month after spawning in aquaria, 38% of the females of P. prideaux started to incubate a second clutch of eggs. Other decapod crustacean species, such as Liocarcinus depurator and Dardanus arrosor, were maintained to use their zoeae as a food source for cephalopod paralarvae. P. prideaux zoeae were used as the sole or main food resource for rearing Loligo vulgaris and Octopus vulgaris, during the first 2 months of life. First feeding and initial growth in L. vulgaris and O. vulgaris paralarvae can be successfully stimulated using decapod zoeae with a total length equivalent to 50–100% of the cephalopod's mantle length.

Recognition of food in Octopus digestive tract

Serological techniques, using antibodies to identify prey proteins, have been applied to the determination of meal composition in cephalopods. This paper investigates the sensitivity of these techniques with respect to the persistence of identity of an individual prey source with time after ingestion and in the presence of other food items. Octopus vulgaris (Cuvier, 1797) were fed single species meals of crab ( Carcinus mediterraneus Czerniavsky) or hermit crab ( Dardanus arrosor Herbst or Eupagurus prideauxi Leach) and mixed meals, where crab and hermit crab were offered as parts of the same meal or as separate meals, 5–10 h apart. Ingested material was recovered from sections of the gut lumen (viz., the crop, stomach, caecum, and intestine), and in fluid and tissue sample extracts taken from the digestive gland. These samples were tested for positive reaction with antisera raised in rats to the prey species used in the feeding experiments. In vitro, the reaction between mammalian antibodies and the proteins (antigens) to which they have been raised, typically results in the formation of high molecular weight antibody/antigen complexes which precipitate under appropriate conditions. The sensitivities of two related immunoelectrophoretic techniques used to visualize these immunoprecipitates, crossed immunoelectrophoresis (CIE) and fused-rocket immunoelectrophoresis (FRIE) were assessed and compared. Digestive gland tissue extracts gave much stronger reactions than gut lumen or digestive gland fluid samples at all sampling times up to 20 h after feeding. After 10 h, meal identification was possible in 94% of cases, using digestive gland material and in a maximum of 55% of cases using gut lumen samples. In mixed meals, recognition of individual meal components was possible. FRIE proved the more sensitive of the two detection techniques but a miniaturization of CIE was successfully applied and is described.

Levels of Copper and Zinc in Tissues of the Hermit Crab Dardanus Arrosor (Herbst) From the Barcelona Coast (Decapoda, Anomura)

[Les taux de Zn et de Cu (ppm poids sec) des branchies, tissus nerveux, coeur et hepatopancreas de Dardanus arrosor (Decapoda, Anomura, Fam. Diogenidae) sont analyses par Spectrophotometrie d'Absorption Atomique. Il n'existe pas de differences sexuelles entre les taux de ces metaux. L'hepatopancreas presente la concentration la plus elevee de cuivre, suivi des branchies, des tissus nerveux et finalement du cœur. La concentration de Zn est semblable dans l'hepatopancreas et les branchies, mais plus basse dans les tissus nerveux et le coeur. Les taux de zinc et de cuivre dans les branchies et l'hepatopancreas presentent une correlation positive. Le taux de cuivre dans l'hepatopancreas et le taux de zinc dans les branchies semblent en correlation negative avec le poids du corps. Les concentrations en zinc et en cuivre sont en correlation negative avec le poids sec des branchies. Dans l'hepatopancreas le cuivre est en correlation negative avec le poids sec., Les taux de Zn et de Cu (ppm poids sec) des branchies, tissus nerveux, coeur et hepatopancreas de Dardanus arrosor (Decapoda, Anomura, Fam. Diogenidae) sont analyses par Spectrophotometrie d'Absorption Atomique. Il n'existe pas de differences sexuelles entre les taux de ces metaux. L'hepatopancreas presente la concentration la plus elevee de cuivre, suivi des branchies, des tissus nerveux et finalement du cœur. La concentration de Zn est semblable dans l'hepatopancreas et les branchies, mais plus basse dans les tissus nerveux et le coeur. Les taux de zinc et de cuivre dans les branchies et l'hepatopancreas presentent une correlation positive. Le taux de cuivre dans l'hepatopancreas et le taux de zinc dans les branchies semblent en correlation negative avec le poids du corps. Les concentrations en zinc et en cuivre sont en correlation negative avec le poids sec des branchies. Dans l'hepatopancreas le cuivre est en correlation negative avec le poids sec.]

The association between the paguridDardanus arrosor and theactinianCalliactis parasitica. Recovery of activity in “Inactive”D. arrosorin the presence of cephalopods

The pagurid Dardanus arrosor loses its activity towards its symbiotic actinian, Calliactis parasitica, after long confinement in an aquarium not containing octopus. The revival of the activity of inactive Dardanus in the presence of octopus, reported by Balasch and Mengual (1974), has been confirmed. Direct contact with the octopus is not necessary for the effect; activity returns when the pagurid receives only the effluent from a tank containing an octopus. The activity does not return when visual cues only are provided. The chemoreceptors involved are not located on the antennules. Effluents from three octopod species and from a cuttlefish restored activity towards Calliactis in Dardanus which had become inactive. The results are discussed in relation to the triggering of the behaviour pattern of Dardanus towards Calliactis.

'Stealing' of the symbiotic anemone, Calliactis parasitica, in intraspecific and interspecific encounters of three species of Mediterranean pagurids

The pagurids Dardanus arrosor, Paguristes oculatus, and Pagurus alatus occur together near Banyuls-sur-Mer in the Western Mediterranean with the anemone Calliactis parasitica on their shells. In intraspecific encounters, the transfer of Calliactis from one individual to another was an infrequent event, occurring in only 6% of tests between two D. arrosor and even less often in tests on P. oculatus and P. alatus. In interspecific encounters, D. arrosor stole Calliactis from P. oculatus in every test and from P. alatus in over 80% of tests. Neither of these species stole Calliactis from D. arrosor. Dardanus arrosor stole Calliactis from P. oculatus without interacting with the pagurid, but with P. alatus in a confined space it extracted the pagurid from its shell and then either transferred the anemone or took over the shell. In a less confined space P. alatus, being more agile and able to run faster, usually escaped capture by D. arrosor. The implications of the apparent dominance of D. arrosor over P. oculatus and P. alatus are discussed in relation to the distribution and the interactions of these species in their benthic habitat.

The presence of α-doradexanthin in crustacea and its possible metabolic fate

α-Doradexanthin has been isolated from the brachyurans Pachygrapsus marmoratus, Eriphia spinifrons and the anomouran Clibanarius erythropus. Small traces of this carotenoid have been also reported in the brachyuran species Potamon edulis and Eriocheir sinensis, but was absent from the anomouran species Dardanus arrosor and Pagurus prideauxi. A transformation pathway of lutein into astaxanthin via α-doradexanthin is suggested.

Distribution ofcalliactis parasiticaon gastropod shells inhabited bydardanus arrosor

Gastropod shells inhabited by Dardanus arrosor are covered by several epibionts. Calliactis parasitica is the only associate with which the hermit crab can establish the partnership through active behaviour Sea‐anemones are not randomly distributed on the shell in freshly collected animals. From laboratory experiments in which the shell is deprived at first from one sea‐anemone and then from all, the spatial structure of the new association obtained by Dardanus is essentially the same as shown in freshly collected animals The structure of associations (not related either to sex or to shell type) suggests other vantages besides protection and camouflage, as correction of some gravitational characteristics of the shell which may be important in walking.

The behavior ofDardanus arrosorin association withCailiactis parasiticain artificial habitat

In the artificial habitat of an aquarium specimens of hermit crabs carrying commensal sea anemones gradually lose their anemones, surprisingly because the crabs frequently damage or eat them. On the Mediterranean association Dardanus arrosor and Calliactis parasitica, the influence of feeding, of population density, or the activity of Dardanus towards Calliactis, and the presence or absence of a predator, were investigated as possible factors responsible for the disappearance of the anemone and the anomalous behavior of the crabs. Both lack of food and high population density increased the numbers of anemones that disappeared. It was noted that these artificial conditions probably do not occur in the natural habitat. All freshly collected Dardanus (both sexes), and presumably all Dardanus in their natural habitat, are active in acquiring Calliactis but during 4–5 months in the aquarium most of this activity is lost. In the presence of a probable predator, the octopus Eledone, these inactive crabs become a...

The association between the hermit crab Dardanus arrosor (Herbst) and the sea anemone Calliactis parasitica (Couch)

The association between Calliactis parasitica and the Mediterranean hermit crab, Dardanus arrosor , has been re-examined. It was confirmed that, unlike the Atlantic crab, Pagurus bernhardus , Dardanus arrosor can display an active behaviour pattern which assists the transfer of Calliactis to its shell. Extensive trials showed, however, a marked tendency for crabs to divide into two groups: ‘performers’, which show this behaviour almost without fail; ‘non-performers’, which almost never show this activity. Most of the ‘performers’ were females and the ‘non-performers’ males. Calliactis frequently transfers to Dardanus -occupied shells without the crab’s help. Actively ‘performing’ Dardanus often fail to transfer Calliactis to their shells. Observations on these cases and experiments with inactivated shells show that for successful crab-aided transfers the co-operation of the anemone is necessary. This co-operation depends on a response of the tentacles to the shell. Apparently it is similar to the ‘clinging’ response to Buccinum shells at Plymouth, now known to depend on a molluscan shell-factor. Crabs and anemones from the Atlantic and the Mediterranean are able to form associations and display their normal behaviour patterns in response to individual partners from the other population. The results are discussed in relation to the possible origins and advantages of the association to the two partners in the two cases.