Search results for "Mphi"
showing 10 items of 626 documents
Spines and behaviour as defences against fish predators in an invasive freshwater amphipod.
2006
7 pages; International audience; Selective predation may be an important proximate cause of the success or failure of invader species. Gammarus roeseli is an invasive amphipod, for which the causes of establishment in rivers where the native species, Gammarus pulex, predominates remain unstudied. Freshwater amphipods are important prey for numerous fish predators, but empirical evidence of lower predation rates on exotic prey is scarce. In laboratory experiments, we compared the susceptibility of G. pulex and G. roeseli to fish predation, determined the mechanisms influencing prey selection, and studied the interaction between behavioural and morphological defences. Fish predators (brown tr…
The ‘killer shrimp’Dikerogammarus villosus(Crustacea, Amphipoda) invading Alpine lakes: overland transport by recreational boats and scuba-diving gea…
2013
The alien freshwater amphipod of Ponto-Caspian origin, Dikerogammarus villosus, also known as the killer shrimp, is recognized as being one of the worst invasive alien species in Europe, representing a major conservation problem. Recently, the species has been reported to invade lakes in the Alps in putative association with overland transport linked with recreational activities. This study provided a method to assess risk associated with this overland transport and an opportunity to set up a rationale for effective preventive conservation management. A field survey of 60 lakes encompassing all the Alpine area has revealed the presence of killer shrimp in 12 lakes. Subsequent multivariate d…
Carotenoids of two freshwater amphipod species (Gammarus pulex and G. roeseli) and their common acanthocephalan parasite Polymorphus minutus
2004
Carotenoid compositions of two freshwater Gammarus species (Crustacea: Amphipoda) and of their common acanthocephalan parasite Polymorphus minutus were characterized. The effect of carotenoid uptake by the parasite was addressed by comparing the carotenoid content of uninfected and infected female hosts. Using high-pressure liquid chromatography (HPLC), co-chromatography of reference pigments and electron ionization mass spectrometry of collected HPLC fractions (EI-MS), several xanthophylls and non-polar compounds were identified. Seven kinds of carotenoids, mainly xanthophylls, were identified in gammarids. Astaxanthin was predominant, amounting to 40 wt.% of total carotenoid in both uninf…
Isolation and characterization of 8 microsatellite loci for the "killer shrimp'', an invasive Ponto-Caspian amphipod Dikerogammarus villosus (Crustac…
2015
5 pages; International audience; Dikerogammarus villosus is a freshwater amphipod of the Ponto-Caspian origin recognized as one of the 100 worst alien species in Europe, having negative impact on biodiversity and functioning of the invaded aquatic ecosystems. The species has a wide ecophysiological tolerance and during the last 20 years it has rapidly spread throughout European inland waters. In consequence, it presents a major conservation management problem. We describe eight polymorphic microsatellite loci developed for D. villosus by combining a biotin-enrichment protocol and new generation 454GS-FLX Titanium pyrosequencing technology. When genotyped in 64 individuals from two locations…
Dikerogammarus villosus (Sowinsky, 1894) (Crustacea, Amphipoda) colonizes next alpine lake – Lac du Bourget, France
2007
Dikerogammarus villosus has been recorded for the first time in the alpine lake – Lac du Bourget, French Alps. Low abundance of the alien species in gathered samples suggests that the colonization is just in its initial stage. Two native gammarid species: Gammarus fossarum (Koch, 1835) and G. pulex (Linnaeus, 1758) are still present in the lake. The invader has most probably reached the lake through the Canal de Savieres joining the lake to the Rhone River in which it has been already present since late 1990s.
Comparison of the functional responses of invasive and native amphipods
2008
While we can usually understand the impacts of invasive species on recipient communities, invasion biology lacks methodologies that are potentially more predictive. Such tools should ideally be straightforward and widely applicable. Here, we explore an approach that compares the functional responses (FRs) of invader and native amphipod crustaceans. Dikerogammarus villosus is a Ponto-Caspian amphipod currently invading Europe and poised to invade North America. Compared with other amphipods that it actively replaces in freshwaters, D. villosus exhibited significantly greater predation, consuming significantly more prey with a higher type II FR. This corroborates the known dramatic field imp…
Zu den Ursachen der unterschiedlichen pH-Empfindlichkeit vonGammarus pulex L., G.fossarum KOCH (Amphipoda) undAselus aquaticus L. (Isopoda)
1992
By means of ion chromatography the extensive and significantly higher loss of ions of G. pulex and G. fossarum in acid water (pH 3.0) as compared to neutral water is proved. While cations are being accumulated in the water, some ions (Na+, Cl−) leave the hemolymph in important percentage, others increase highly after being set free from the cells (K+ and Ca2+). The loss of cations with Asellus aquaticus in acid water (pH 3) is clearly lower than with Gammarus, and it is not significantly higher than when the animals are put into neutral water.
Sediment quality assessment using Gmelinoides fasciatus and Monoporeia affinis (Amphipoda, Gammaridea) in the northeastern Baltic Sea
2013
Crustaceans in the order Amphipoda are sensitive organisms for the assessment of sediment quality. In this work we performed 10-day toxicity tests on muddy sediments collected from a total of 29 sites in the Gulf of Finland, the Gulf of Riga and the Gulf of Bothnia (northeastern Baltic Sea) using Baltic Sea species such as the native amphipod Monoporeia affinis (Bousfield, 1989) and the invasive amphipod Gmelinoides fasciatus (Stebbing, 1899), and also compared these results with those of bioassays carried out using the standard test species, laboratory-cultivated amphipod Hyalella azteca (Saussure, 1858). The sediment samples (three cm of the upper layer) were collected by a GEMAX Dual Cor…
Gli anfiteatri di Campania e Sicilia, 'pietre miliari' nella storia della tutela in età borbonica. Amphitheatres of Campania and Sicily, ‘milestones’…
2017
Il breve studio vuole essere occasione per richiamare le vicende legate alla progressiva salvaguardia del patrimonio culturale dell'Italia meridionale, al tempo dei Borbone. Sottolineando l'opportunità di riprendere, in un disegno complessivo, il quadro relativo ai due regni - di Napoli e di Sicilia - per le interrelazioni ancora da studiare e porre in evidenza, il saggio si sofferma in modo specifico sulle ricadute che le azioni condotte sugli anfiteatri campani avevano su quelli siciliani. Si è ripercorso l'iter di tutela e restauro degli anfiteatri e dei teatri di Catania e Siracusa, alla luce di una chiave critica e interpretativa formulata nel secondo Novecento, relativa al progressivo…
Homogeneous Langmuir-Blodgett Film of Double-Chain Ammonium Amphiphile Complexed with Anionic Polymer
1988
Heterogeneous textures suggesting the coexistence of a fluid and a solid phase were found both in a surface monolayer and in a deposited Langmuir-Blodgett (LB) film of double-chain ammonium amphiphiles by fluorescence microscopy. Although an annealing of the surface monolayer at 40°C allowed crystal growth, the heterogeneous phase separation remained in the LB film. A drastic change of the fluorescence image shows that the recrystallization of the complexed monolayer with anionic polymers conducted the homogeneous monolayer.