Search results for "Fora"
showing 10 items of 1086 documents
Speed-accuracy trade-off and its consequences in a scramble competition context.
2014
Abstract: Animals foraging in groups commonly respond to the presence of others by increasing their foraging rate, an increase that could come at the expense of prey detection accuracy. Yet the existence and consequences of such so-called 'speed-accuracy trade-offs' in group-foraging animals remain unexplored. We used group-feeding zebra finches, Taeniopygia guttata, to determine how search speed affects food detection accuracy and how a potential speed-accuracy trade-off influences feeding success. We found significant between-individual differences in hopping speed as well as evidence that faster individuals were more likely to overlook food, demonstrating the existence of a trade-off bet…
Distribution and ecology of the Globigerinoides ruber — Globigerinoides elongatus morphotypes in the Azores region during the late Pleistocene-Holoce…
2018
Abstract Globigerinoides ruber is the dominant taxon in the North Atlantic Subtropical Gyre, nowadays limited to the north by the Azores Current. It is highly sensitive to recent and late Pleistocene Azores Front Current System variability. In this study, we analyse the distribution of five individual morphotypes of the G. ruber – G. elongatus plexus (G. ruber s.s., G. ruber cyclostoma type, G. elongatus, G. elongatus cf.1, G. elongatus pyramidical type) and G. ruber kummerform gr. in a core (ATA13-OF-KT1) collected southwest of the Azores islands and located in a strategical position near the present-day boundary of the Subtropical Gyre/Azores Front Current System (STG/AFCS). Micropaleonto…
Functional ecology for evaluating and predicting the aptitude of permanent grassland to provide services
2013
National audience; Applying the principles of functional ecology helps better predict the services which can be provided by permanent grassland. Farming practices and environmental characteristics influence the functional composition of grassland. Functional plant types have a generic effect on forage services which can be assessed. 13 types of grassland composed of distinct functional types were defined based on 1,283 sample grassland fields located on 8 sites. This approach was validated by checking 8 Ellenberg indicator values (used to evaluate environmental characteristics and farming practices) against climatic data and descriptive data for farming practices. The interest of a function…
Parasite-induced alteration of plastic response to predation threat: increased refuge use but lower food intake in Gammarus pulex infected with the a…
2014
6 pages; International audience; Larvae of many trophically-transmitted parasites alter the behaviour of their intermediate host in ways that increase their probability of transmission to the next host in their life cycle. Before reaching a stage that is infective to the next host, parasite larvae may develop through several larval stages in the intermediate host that are not infective to the definitive host. Early predation at these stages results in parasite death, and it has recently been shown that non-infective larvae of some helminths decrease such risk by enhancing the anti-predator defences of the host, including decreased activity and increased sheltering. However, these behavioura…
Les impacts du campagnol terrestre sur les systèmes fourragers : le cas de l’élevage bovin allaitant en Bourgogne
2014
EAAgroSupECOLDUR; Do vole outbreaks have the same effects on suckler beef farms in Burgundy as they do on daily farms in Auvergne and Franche-Comte? Semi-structured interviews were carried out with 19 farmers from Burgundy who had been affected by a water vole outbreak in 2011. The results indicate that, just like farmers in Auvergne and Franche-Comte, farmers in Burgundy witnessed a decrease in forage quantity and quality. Farmers used diverse measures to deal with the outbreak (e.g., avoidance strategies or the use of bromadiolone). Farmers that described water voles as pests were more likely to have used bromadiolone, while those who described water voles in morphological terms or in ter…
Effets de la variabilité inter-individuelles et des interactions intra-guildes sur les stratégies d'approvisionnement de carabes consommateurs de gra…
2017
Making a choice requires, implicitly, an investment of time in one behaviour at the expense of an investment in another. Being choosy would increase the risk of losing many food item opportunities to competitors, and is directly in conflict with other essential tasks such as predator avoidance. Individuals are thus expected to adjust their level of choosiness in response to the competition and predation context. The available behavioural ecological theory and the empirical ecology of carabids would suggest that competition and predation interference induces changes in the foraging behaviour of carabid individuals. Carabids typically operate within communities in which competition and predat…
Effects of biomass, age and functional traits on regrowth of arable weeds after cutting
2008
Conference: 24th German Conference on Weed Biology and Weed ControlLocation: Stuttgart Hohenheim, GERMANYDate: MAR 04-06, 2008; International audience; In sown field margin stripes or pluriannual forage crops, arable weeds are exposed to high competition and regular mowing or hay cutting, to which they may react very differently. A greenhouse experiment permitted to understand some key factors shaping the ability of common arable weeds and forage crops to grow after such cuttings. Even without competition, cutting shoots at 5cm height reduced biomass production of all 10 species studied, but 6 annual broadleaf weeds were much more affected than 2 perennial forage crops (Dactylis, Medicago) …
Gestion du pâturage au printemps en système bovin allaitant : diversité des pratiques en Saône-et-Loire
2009
National audience; Grazed grass is the cheapest forage for making meat'. In order to incite farmers to make their forage systems more self-sufficient and thrifty, the 'Chambre d'Agriculture de Saone-et-Loire' (a professional agricultural organization for that departement) has been monitoring for five years the management of spring grazing on 23 farms. The analysis of farmers' practices lead to considerations as to put to the best use the grazed grass, according to the pedo-climatic conditions and the constraints of the farms. With the aim of optimizing the pasture resources in order to limit the purchase of concentrates and to cope with the climatic hazards, the study of the management of s…
Légumineuses et prairies temporaires : des fournitures d'azote pour les rotations
2015
Intervention présentée aux Journées de l'AFPF, "La fertilité des sols dans les systèmes fourragers", les 8 et 9 avril 2015; Les atouts des légumineuses (fixation symbiotique, diversité fonctionnelle...) leur permettent de contribuer à la fertilité des sols, à l'amélioration de la durabilité de l'agriculture et de l'autonomie protéique des systèmes alimentaires. Il convient donc de mieux connaître leurs rôles, directs et indirects, dans les flux d'azote des rotations.Les légumineuses fourragères (en culture pure ou dans des couverts multispécifiques) représentent une grande part des apports azotés symbiotiques. Il existe une grande diversité d'implication des légumineuses dans les rotations.…
Can obligatory omnivore carabids be useful for the biocontrol of weeds?
2017
National audience; Many thousands of carabid individuals exist in farm fields, in communities of carnivore and opportunistic (e.g. granivores) and obligate omnivore guilds. As carabids can eat a substantial amount of weed seeds they are considered as credible biocontrol agents for the regulation of weeds in arable fields. Some studies have suggested that “granivores” are more important biocontrol agents than obligate omnivorous species. Yet, in some instances, obligate omnivores are very abundant and appear to drive the predation of weeds leading some authors to question whether specialist natural enemies are better. Moreover, niche complementarity, facilitation and interference (i.e. intra…