scholarly journals Filtering out parasites: sand crabs (Lepidopa benedicti) are infected by more parasites than sympatric mole crabs (Emerita benedicti)

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3852
Author(s):  
Zen Faulkes
Keyword(s):  
Parasite Species ◽  
Neural Tissue ◽  
Fine Sand ◽  
Swash Zone ◽  
Crab Species ◽  
Decapod Crustaceans ◽  
Primary Host ◽  
Litopenaeus Setiferus ◽  
Infection Pattern ◽  
Behavioural Tests

Two digging decapod crustaceans, the sand crab speciesLepidopa benedictiand the mole crab speciesEmerita benedicti, both live in the swash zone of fine sand beaches. They were examined for two parasites that infect decapod crustaceans in the region, an unidentified nematode previously shown to infectL. benedicti, and cestode tapeworm larvae,Polypocephalussp., previously shown to infect shrimp (Litopenaeus setiferus).Lepidopa benedictiwere almost always infected with both parasite species, whileE. benedictiwere rarely infected with either parasite species. This difference in infection pattern suggests that tapeworms are ingested during sediment feeding inL. benedicti, whichE. benedictiavoid by filter feeding. LargerL. benedictihad morePolypocephalussp. larvae. The thoracic ganglia, which make up the largest proportion of neural tissue, contained the largest numbers ofPolypocephalussp. larvae. Intensity ofPolypocephalussp. infection was not correlated with how longL. benedictiremained above sand in behavioural tests, suggesting thatPolypocephalussp. do not manipulate the sand crabs in a way that facilitates trophic transmission of the parasite.Litopenaeus setiferusmay be a primary host forPolypocephalussp., andL. benedictmay be a secondary, auxiliary host.

scholarly journals Decapod crustaceans used as food by the Yanomami Indians of the Balawa-ú village, State of Amazonas, Brazil

2006 ◽  
Vol 36 (3) ◽  
pp. 369-374 ◽  
Author(s):  
Célio Magalhães ◽  
Ulysses C. Barbosa ◽  
Victor Py-Daniel
Keyword(s):  
American Indians ◽  
Food Item ◽  
Wild Food ◽  
South American ◽  
Crab Species ◽  
Decapod Crustaceans ◽  
Shrimp Species ◽  
South American Indians ◽  
The Family ◽  
The Village

The Yanomami are a group of South American Indians that live in the rainforest along the borderlands of Brazil and Venezuela. They depend on hunting, gardening and wild food for survival; crustaceans are a highly prized food item in their diet. Taxonomical and ethnozoological aspects of the Yanomami Indians of the Balawa-ú village, state of Amazonas, Brazil, related to the crustaceans are described. Information and specimens were obtained from August to December, 2003. Interviews were conducted with residents of the village and focused on questions about species exploited, indigenous names, modes of capture and use of the species. One shrimp species of the family Palaemonidae (Macrobrachium brasiliense) and two crab species of Trichodactylidae (Sylviocarcinus pictus, Valdivia serrata) as well as two of Pseudothelphusidae (Fredius fittkaui, F. platyacanthus) were recorded. The indigenous names applied to these species are: shuhu, for shrimp, oko and peimatherimi for each of the two pseudothelphusid crabs, and hesiki tôtôrema for both trichodactylid crabs.

Effect of intermediate host size (Cerastoderma edule) on infectivity of cercariae of Himasthla quissetensis (Echinostomatidae: Trematoda)

2005 ◽  
Vol 85 (4) ◽  
pp. 809-812 ◽  
Author(s):  
Xavier de Montaudouin ◽  
K. Thomas Jensen ◽  
Céline Desclaux ◽  
Anne M. Wegeberg ◽  
Marie C. Sajus
Keyword(s):  
Shell Length ◽  
Parasite Species ◽  
Host Size ◽  
Marine Bivalve ◽  
Free Living ◽  
Experimental Procedure ◽  
Cerastoderma Edule ◽  
Infection Pattern ◽  
South West ◽  
Fourth Species

The edible cockle (Cerastoderma edule), a common marine bivalve in semi-sheltered sandflats, is a natural host for many parasite species of the genus Himasthla (Echinostomatidae: Trematoda). In a previous paper, Wegeberg et al. (1999) showed segregation of cockle infection by three Himasthla species (H. interrupta, H. continua, H. elongata) in relation to host tissue (foot, mantle, siphon) and host size (1·5 to 14 mm shell length). Following the same experimental procedure, a fourth species, H. quissetensis, an introduced dominant parasite of cockles in Arcachon Bay (south-west France) was investigated. The infection pattern was very similar to the patterns shown by H. elongata and H. continua. Cercariae (the free-living stage shed from prosobranch snails and encysting as metacercariae in bivalves) were most successful in the shell-length range of 6–14 mm, where 74% of the added cercariae were recovered as metacercariae. The comparison with the other Himasthla species supports the previous conclusion that the efficiency of cercariae to infect cockles depends on host size.

scholarly journals Nematode infection patterns in a Neotropical lizard species from an insular mountain habitat in Brazil

2016 ◽  
Vol 91 (5) ◽  
pp. 578-582 ◽  
Author(s):  
A.B.H.P. Václav ◽  
L.A. Anjos ◽  
M.S. Queiróz ◽  
L.B. Nascimento ◽  
C.A.B. Galdino
Keyword(s):  
Seasonal Changes ◽  
Parasite Species ◽  
Dry Period ◽  
Intensity Of Infection ◽  
Lizard Species ◽  
Rainy Period ◽  
Diet Patterns ◽  
Infection Pattern ◽  
Host Body Size ◽  
Nematode Fauna

AbstractNeotropical lizards are known to harbour rich nematode parasite faunas; however, knowledge of the diversity and patterns of infection are still lacking for many species. This is true for the genus Tropidurus, in which data on patterns of parasitism are known for only approximately 11 of its 30 species. We show that the nematode fauna associated with a population of Tropidurus montanus is composed of three species of host-generalist parasites with high overall prevalence. Male and female lizards did not differ in infection pattern and there was no relationship between host body size and intensity of infection for the most prevalent parasite species. Nevertheless, overall prevalence changed seasonally, with a higher proportion of parasitized individuals being found in the dry period than in the rainy period. We discuss our findings in the context of diet patterns of T. montanus, which we suggest may explain the similarities in prevalence and intensity of infection between the sexes. In addition, seasonal changes in diet are considered to be related to the observed differences in prevalence between dry and rainy periods.

scholarly journals MEASUREMENT AND MODELING OF THE INFLUENCE OF GRAIN SIZE AND PRESSURE GRADIENTS ON SWASH ZONE SEDIMENT TRANSPORT

2012 ◽  
Vol 1 (33) ◽  
pp. 58
Author(s):  
Ilya Khairanis Othman ◽  
Tom E. Baldock ◽  
David P. Callaghan
Keyword(s):  
Grain Size ◽  
Sediment Transport ◽  
Pressure Gradient ◽  
Transport Model ◽  
Fine Sand ◽  
Coarse Sand ◽  
P Value ◽  
Gradient Term ◽  
Swash Zone ◽  
Transport Calculation

The paper examines the dependency between sediment transport rate, q, and grain size, D, (i.e. q∝Dp) in the swash zone. Experiments were performed using a dam break flow as a proxy for swash overtopping on a mobile sediment beach. The magnitude and nature of the dependency (i.e. p value) is inferred for different flow parameters; the initial dam depth (or initial bore height), do, the integrated depth averaged velocity, ∫u3 dt, and against the predicted transport, qp using the Meyer-Peter Muller (MPM) transport model. Experiments were performed over both upward sloping beds and a horizontal bed. The data show that negative dependencies (p0) are obtained for ∫u3 dt. This indicates that a given do and qp transport less sediment as grain size increases, whereas transport increases with grain size for a given ∫u3 dt. The p value is expected to be narrow ranged, 0.5≤ p≤-0.5. A discernible difference observed between the measured and predicted transport on horizontal and sloping beds suggests different modes of transport. The incorporation of a pressure gradient correction, dp/dx, using the surface water slope (i.e. piezometric head), in the transport calculation greatly improved the transport predictions on the horizontal bed, where dp/dx is positive. On average, the incorporation of a pressure gradient term into the MPM formulation reduces qp in the uprush by 4% (fine sand) to 18% (coarse sand) and increases qp over a horizontal bed by 1% (fine sand) to two orders of magnitude (coarse sand). The measured transport for fine and coarse sand are better predicted using MPM and MPM+dp/dx respectively. Poor predictions are obtained using Nielsen (2002) because the pressure gradient in the uprush is of opposite sign to that inferred from velocity data in that paper. It is suggested that future swash sediment transport models should incorporate the grain size effect, partly through the pressure gradient, although the dp/dx influence is small for fine sands because of the grain size scaling contained in the stress term.

A Quantitative Survey of the Macrobenthos of Western Port, Victoria

1978 ◽  
Vol 29 (4) ◽  
pp. 445 ◽  
Author(s):  
N Coleman ◽  
W Cuff ◽  
M Drummond ◽  
JD Kudenov
Keyword(s):  
Species Diversity ◽  
Industrial Development ◽  
Population Distribution ◽  
Fine Sand ◽  
Sediment Type ◽  
Decapod Crustaceans ◽  
Medium Sand ◽  
Quantitative Survey ◽  
Faunal Assemblages ◽  
Regional Estimates

The results of the first bay-wide quantitative survey of the invertebrate macrobenthos of Westeln Port, Victoria (145� E., 38�S.) are presented. Three 0.1-m² samples were taken with a Smith- McIntyre grab at each of 41 randomly selected sampling stations, and the results were used to provide both bay-wide and regional estimates of population distribution and abundance. More than 19 600 individuals were collected, and 572 species identified. The fauna is dominated by polychaetes, crustaceans and molluscs which provided respectively 54.1, 31.7 and 6.6% of the individuals collected and 35.7,47.7 and 10.3 % of the species identified. Comparison of faunal affinity between stations showed two major faunal assemblages whose distributions are linked with sediment type. These assemblages are a 'clean medium sand' assemblage distributed in the deeper (> 5.5 rn) sublittoral channel areas, and a 'fine sand and mud' assemblage distributed over the tidal flats and in shallow (< 5.5 m) sublittoral areas. Species characteristic of the 'clean medium sand' assemblage are the polychaetes Scoloplos spp. 1-4, Rhodine sp. and Travisia sp. ; the bivalves Neotrigonia margaritacea, Notocallista diemenensis, Solen vaginoides and Venericardia bimaculata; and the crustaceans Halicarcinus rostratus, Ampelisca sp., Cheirighotis megacheles, Leptanthura diemenensis and Paranchialina angusta. Characteristic of the 'fine sand and mud' assemblage are the polychaetes Amaeana sp. and Mediomastus sp.; the bivalves Tellina deltoidalis, T. mariae and Katelysia rhytiphora; and the decapod crustaceans Pontophilus intermedius, Macrobrachium intermedium, Halicarcinus ovatus and Litocheira bispinosa. A third, minor assemblage was also recognized. This contains the stations nearest to Hastings, the largest centre of urban and industrial development in the bay. The fauna at these stations is impoverished in species and low in species diversity. Both affinity analyses and survey statistical analyses were applied to the data. The advantages and limitations of each are discussed.

Our understanding of neural codes rests on Shannon's foundations

2019 ◽  
Vol 42 ◽  
Author(s):  
Charles R. Gallistel
Keyword(s):  
Brain Structure ◽  
Neural Tissue ◽  
Neural Codes ◽  
Flow Of Information

Abstract Shannon's theory lays the foundation for understanding the flow of information from world into brain: There must be a set of possible messages. Brain structure determines what they are. Many messages convey quantitative facts (distances, directions, durations, etc.). It is impossible to consider how neural tissue processes these numbers without first considering how it encodes them.

Actin filaments in two spermatozoa of crustacea decapoda

1990 ◽  
Vol 48 (3) ◽  
pp. 70-71
Author(s):  
E. Dupré ◽  
G. Schatten
Keyword(s):  
Electron Microscopy ◽  
Actin Filaments ◽  
Low Voltage ◽  
Active Role ◽  
Main Body ◽  
Robinson Crusoe ◽  
Decapod Crustaceans ◽  
Actual Participation ◽  
Voltage Scanning ◽  
Scanning Electron

Sperm of decapod crustaceans are formed by a round or cup-shaped body, a complex acrosome and one a few appendages emerging from the main body. Although this sperm does not have motility, it has some components of the cytoskeleton like microtubules, which are found inside the appendages. Actin filaments have been found in the spike of penaeidae sperms. The actual participation of the crustacean decapod sperm cytoskeleton during fertilization is not well understood. Actin is supposed to play an active role in drawing the penaeidae shrimp sperm closer to the egg after bending of the spike. The present study was aimed at the localization of actin filaments in sperm of the Robinson Crusoe island lobster, Jasus frontalis and in the crayfish Orconectes propincus, by fluorescent probes and low voltage scanning electron microscopy.

Metazoan Parasites and Health State of European Eel, Anguilla Anguilla (Anguilliformes, Anguillidae), From Tonga Lake and El Mellah Lagoon in the Northeast of Algeria

2018 ◽  
Vol 52 (4) ◽  
pp. 279-288 ◽  
Author(s):  
F. Bakaria ◽  
S. Belhaoues ◽  
N. Djebbari ◽  
M. Tahri ◽  
I. Ladjama ◽  
...  
Keyword(s):  
Brackish Water ◽  
Parasite Species ◽  
Anguilla Anguilla ◽  
European Eel ◽  
Health State ◽  
Component Community ◽  
Metazoan Parasites ◽  
Parasite Communities ◽  
High Dominance ◽  
Argulus Foliaceus

Abstract The aim of the study was to examine metazoans parasite communities of European eels (Anguilla anguilla) in freshwater (Tonga Lake) and brackish water (El Mellah lagoon) in the northeast of Algeria. Six parasite taxa were collected: one monogenean, Pseudodactylogyrus sp.; two crustaceans, Ergasilus sp. and Argulus foliaceus; two nematodes, Cucullanus sp. and Anguillicola crassus; one cestode, Bothriocephalus claviceps. Th e most prevalent parasite taxa in freshwater were Pseudodactylogyrus sp., A. crassus and Bothriocephalus claviceps; whereas in the brackish water, eels were infected mainly with A. crassus. Th e characteristics of the parasite component community structure revealed low parasite species diversity and high dominance values in eels from the two localities. Both communities were dominated by a single parasite species: Tonga eels by the monogenean Pseudodactylogyrus sp. and El Mellah lagoon eels by the nematode A. crassus, verified by high Berger-Parker dominance values of 0.76 and 0.87 respectively.

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