Directions in bivalve feeding

International audienceManuscripts dealing with bivalve feeding and submitted to the Inter-Research journal Aquatic Biology over the course of 2008 were peer-reviewed in the standard manner, and the successful papers compiled for a Theme Issue entitled 'Directions in bivalve feeding'. The historical progression of research in this field is summarized, and the directions of current research highlighted in view of the compiled papers. Some suggestions for future work are presented

Fine-scale spatial distribution of the temperate infaunal bivalve Tapes (= Ruditapes) philippinarum (Adams and Reeve) on fished and unfished intertidal mudflats

a b s t r a c t a r t i c l e i n f o Temperate intertidal mudflats are important to both human and nonhuman foragers, the former for professional and recreational clam fishing, and the latter for food, especially for migratory shorebirds. Foraging strategy and success will depend to a large degree on the spatial distribution of the infaunal prey, which is very poorlyknown at the scale at which these foragers exploit the resources. We characterized the fine-scale spatial distribution of the bivalve Tapes philippinarum on a chronically-fished and on an unfished (reference) mudflat, using autocorrelation, variogram, and fractal analyses. Two cohorts were identified at each site: one sub-legal and one legal size. Although both cohorts were clearly aggregated at the scale of ≤130 m, this aggregation was greatly attenuated at the fishing-impacted site, and most severely for the fished-size cohort. The fractal dimensions of the cohorts at the two sites corroborated the decreased spatial structure at the fishing -impacted site, and in particular for the fished-size cohort. Together with similar observations for other components of this mudflat ecosystem, these results underscore the need to incorporate the spatial aspect in assessments of both organism (prey or resource) distribution, its relationship to foraging strategies, and the effect of intertidal fishing on these processes

Trophic interactions between two introduced suspension-feeders Crepidula fornicata and Crassostrea gigas influenced by seasonal effects and qualitative selection capacity

Abstract The effects of season and qualitative selection capacity on trophic relationships between two sympatric invasive suspensionfeeders, Crepidula fornicata and Crassostrea gigas, were investigated in Bourgneuf Bay (France) from January 2003 to June 2004. Carbon and nitrogen stable isotopic deviations, δ 13 C and δ 15 N, of common Atlantic slippersnails and Pacific oysters were analysed relative to isotopic composition and availability of end-members. Slippersnail deviations were less variable over the sampling period compared with those of oysters. Significant differences between δ 13 C and δ 15 N of C. fornicata and C. gigas were found from winter to early summer, and linked to major isotopic changes in oysters. We identified three distinct seasonal periods: January to March when oysters were 15 N-enriched compared to slippersnails and to themselves at other times of the year, April to June-July when oysters showed a 15 N-depletion and a more marked 13 Cdepletion compared to slippersnails and to themselves at other times of the year, and July-August to December when both species presented similar carbon and nitrogen deviations. Species-specific differences in qualitative selection capability may explain these seasonal differences in isotopic deviations. Whereas the isotopic composition of the indiscriminate suspension-feeding slippersnails reflects the composition of the seston throughout the year, the oyster is capable of qualitative selection. The oyster isotopic compositions are consistent with a facultative activation of selection mechanisms under conditions of qualitative and quantitative food limitation, notably the preferential ingestion and assimilation of the dominant organic source in the suspended pool. We conclude that C. fornicata and C. gigas are trophic competitors only in winter and spring at this site, where detrital endmembers are major POM components. These results underscore (1) the importance of long-term (annual) studies in the evaluation of potential trophic competition, and (2) the necessity to include the qualitative selection capacities of suspension-feeders in future interpretations of trophic relationships in marine coastal ecosystems

A Scientific Name for Pacific Oysters

WOS:000447083800041International audienc

Incentive motivation in first-episode psychosis: A behavioural study

<p>Abstract</p> <p>Background:</p> <p>It has been proposed that there are abnormalities in incentive motivational processing in psychosis, possibly secondary to subcortical dopamine abnormalities, but few empirical studies have addressed this issue.</p> <p>Methods:</p> <p>We studied incentive motivation in 18 first-episode psychosis patients from the Cambridge early psychosis service CAMEO and 19 control participants using the Cued Reinforcement Reaction Time Task, which measures motivationally driven behaviour. We also gathered information on participants' attentional, executive and spatial working memory function in order to determine whether any incentive motivation deficits were secondary to generalised cognitive impairment.</p> <p>Results:</p> <p>We demonstrated the anticipated "reinforcement-related speeding" effect in controls (17 out of 19 control participants responded faster during an "odd-one-out" task in response to a cue that indicated a high likelihood of a large points reward). Only 4 out of 18 patients showed this effect and there was a significant interaction effect between reinforcement probability and diagnosis on reaction time (F_1,35= 14.2, p = 0.001). This deficit was present in spite of preserved executive and attentional function in patients, and persisted even in antipsychotic medication free patients.</p> <p>Conclusion:</p> <p>There are incentive motivation processing abnormalities in first-episode psychosis; these may be secondary to dopamine dysfunction and are not attributable to generalised cognitive impairment.</p

An overview of NMR-based metabolomics to identify secondary plant compounds involved in host plant resistance

Secondary metabolites provide a potential source for the generation of host plant resistance and development of biopesticides. This is especially important in view of the rapid and vast spread of agricultural and horticultural pests worldwide. Multiple pests control tactics in the framework of an integrated pest management (IPM) programme are necessary. One important strategy of IPM is the use of chemical host plant resistance. Up to now the study of chemical host plant resistance has, for technical reasons, been restricted to the identification of single compounds applying specific chemical analyses adapted to the compound in question. In biological processes however, usually more than one compound is involved. Metabolomics allows the simultaneous detection of a wide range of compounds, providing an immediate image of the metabolome of a plant. One of the most universally used metabolomic approaches comprises nuclear magnetic resonance spectroscopy (NMR). It has been NMR which has been applied as a proof of principle to show that metabolomics can constitute a major advancement in the study of host plant resistance. Here we give an overview on the application of NMR to identify candidate compounds for host plant resistance. We focus on host plant resistance to western flower thrips (Frankliniella occidentalis) which has been used as a model for different plant species

Towards eco-friendly crop protection: natural deep eutectic solvents and defensive secondary metabolites

Plant science

Etude comparee de la biochimie, de l'ecophysiologie et de la reproduction chez diverses especes de mollusques bivalves d'interet aquacole

SIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc