Search results for "Crustacea"

Influence of female moulting status on pairing decisions and size‐assortative mating in amphipods

2012

8 pages; International audience; Precopulatory mate guarding is a common strategy, which has evolved in species where the female receptivity (and thus egg fertilization) is predictable, but also limited to a short period. Although males are larger than females in many amphipods, the largest males pair with the largest females, leading to a positive sizeassortative pairing. Size-assortative pairing has received much attention but how moulting physiology could affect pairing decisions has rarely been studied. Here, we tested the hypothesis that the size-assortative pairing in the freshwater amphipod Gammarus pulex is closely related to the female moult cycle. We characterized moulting status …

Assortative mating by size without a size-based preference: the female-sooner norm as a mate-guarding criterion.

2013

7 pages; International audience; The study of size-assortative mating, or homogamy, is of great importance in speciation and sexual selection. However, the proximate mechanisms that lead to such patterns are poorly understood. Homogamy is often thought to come from a directional preference for larger mates. However, many constraints affect mating preferences and understanding the causes of size assortment requires a precise evaluation of the pair formation mechanism. Mate-guarding crustaceans are a model group for the study of homogamy. Males guard females until moult and reproduction. They are also unable to hold a female during their own moult and tend to pair with females closer to moult…

External Influences on Invertebrate Brain Histamine and Related Compounds via an Automated Derivatization Method for Capillary Electrophoresis.

2017

8 pages; International audience; Histamine has been shown to modulate visual system and photic behavior in arthropods. However, few methods are available for the direct quantification of histamine and its precursor and metabolites in arthropod brain. In this work, a method for the separation of histamine, its precursor histidine, and its metabolite N-methyl-histamine from brain extracts of a freshwater crustacean has been developed using capillary electrophoresis with laser-induced fluorescence detection. Molecules were tagged on their primary amine function with naphthalene-2,3-dicarboxaldehyde, but derivatized histamine and N-methyl-histamine exhibited poor stability in contrast to deriva…

Fishing pressure impacts the abundance gradient of European lobsters across the borders of a newly established marine protected area

2019

Marine protected areas (MPAs) are considered viable fisheries management tools due to their potential benefits of adult spillover and recruitment subsidy to nearby fisheries. However, before–after control–impact studies that explore the biological and fishery effects of MPAs to surrounding fisheries are scarce. We present results from a fine-scale spatial gradient study conducted before and after the implementation of a 5 km 2 lobster MPA in southern Norway. A significant nonlinear response in lobster abundance, estimated as catch-per-unit-effort (CPUE) from experimental fishing, was detected within 2 years of protection. After 4 years, CPUE values inside the MPA had increased by a magnitu…

Are epizoites biological indicators of a western Mediterranean striped dolphin die-off?

1994

During a die-off of Mediterranean striped dolphins Stenella coeruleoalba in 1990-91, 82 individuals stranded on the Spanish coast were examined for crustacean ectoparasites and epizoites. Six species were detected: Syncyarnus aequus, PenneUa sp., Xenobalanus globicipitis, Conchoderma virgatum, Lepas pectinata and Lepas cf. hillii. The barnacles L. pectinata and L. cf. hillii are reported here for the first time on cetaceans; they were attached to the teeth. C. virgaturn was also found on the teeth; this is an unusual attachment on cetaceans. X. globicipitis showed a higher prevalence on the dolphins studied than on those stranded in the same months before (1980 to 1990) and after (1991 to 1…

Ecologia d'ostracodes simbionts (Entocytheridae) de carrancs invasors a Europa

2014

Els entocitèrids són una família d'ostracodes (Crustacea) ectosimbionts (bàsicament comensals) d'altres crustacis, majoritàriament decàpodes d'aigua dolça. Gran part de les espècies d'entocitèrids són originàries d'Amèrica del Nord i Central, i d'Oceania, associades a carrancs de riu americans i australians. No s'han descobert espècies d'entocitèrids en els carrancs de riu natius d'Europa. Les darreres dècades, els carrancs natius europeus s'han vist greument perjudicats per la invasió de carrancs exòtics, degut a fenòmens d'exclusió competitiva i transmissió de simbionts parasitaris. En la present tesi, hem avaluat la presència d'entocitèrids associats a carrancs de riu (natius i exòtics) …

Variabilità genetica in Aristeus antennatus (Crustacea, Decapoda) attraverso analisi AFLP (Amplified Fragment Length Polymorphism).

2007

The influence of food competition and host specificity on the transmission of Triaenophorus crassus (Cestoda) and Cystidicola farionis (Nematoda) to …

2000

Abstract As a superior competitor for planktonic food, vendace ( Coregonus albula ), when abundant, is expected to displace whitefish ( Coregonus lavaretus ) from feeding on plankton and to force it to rely more on benthic food. The predicted result would be a reduced abundance of the copepod-transmitted cestode Triaenophorus crassus in whitefish, but an increase in the abundance of the nematode Cystidicola farionis transmitted via benthic amphipods. We studied the occurrence of both parasites in whitefish during 1991–1996 in three interconnected areas at Lake Saimaa, Finland, where the densities of the vendace stocks varied due to natural fluctuation in year-class strengths. In accordance …

Monitoring programme on cadmium, lead and mercury in fish and seafood from Valencia, Spain: levels and estimated weekly intake.

2008

The study was carried out to determine the current levels of mercury, cadmium, and lead in fish and seafood from the market of Comunitat Valenciana, Spain. Levels of total mercury ranged from 0.02 to 3.15 mg kg⁻¹ w.w. (average = 0.073 mg kg⁻¹ w.w.). Cadmium concentrations ranged from 0.003 to 0.66 mg kg⁻¹ w.w. (average = 0.27 mg kg⁻¹ w.w.) for seafood, and between 0.003 and 0.71 mg kg⁻¹ w.w. (average = 0.01 mg kg⁻¹ w.w.) for marine fish. Concerning lead, concentrations from 0.02 to 0.36 mg kg⁻¹ w.w (average = 0.04 mg kg⁻¹ w.w.) were found in fish, and from 0.02 to 1.02 mg kg⁻¹ w.w. in seafood (average = 0.147 mg kg⁻¹ w.w.). The levels found were, in general, lower than maximum levels propos…

Seasonal changes in host phenotype manipulation by an acanthocephalan: time to be transmitted?

2009

Parasitology, 136 (2)