Inter-individual variability in the foraging behaviour of traplining bumblebees

International audienceWorkers of social insects, such as bees, ants and wasps, show some degree of inter-individual variability in decision-making, learning and memory. Whether these natural cognitive differences translate into distinct adaptive behavioural strategies is virtually unknown. Here we examined variability in the movement patterns of bumblebee foragers establishing routes between artificial flowers. We recorded all flower visitation sequences performed by 29 bees tested for 20 consecutive foraging bouts in three experimental arrays, each characterised by a unique spatial configuration of artificial flowers and three-dimensional landmarks. All bees started to develop efficient routes as they accumulated foraging experience in each array, and showed consistent inter-individual differences in their levels of route fidelity and foraging performance, as measured by travel speed and the frequency of revisits to flowers. While the tendency of bees to repeat the same route was influenced by their colony origin, foraging performance was correlated to body size. The largest foragers travelled faster and made less revisits to empty flowers. We discuss the possible adaptive value of such inter-individual variability within the forager caste for optimisation of colony-level foraging performances in social pollinators

Individual identification and marking techniques for zebrafish

In laboratory fish research, the zebrafish Danio rerio (Cyprinidae) represents the equivalent of the mouse in mammalian research. This species has become a major model for studies in developmental and behavioural genetics, neurophysiology, biomedicine, ecotoxicology, and behavioural and evolutionary ecology. To meet the need for accurate and reproducible data in both fundamental and applied sciences, it is of primary importance to be able to tag and/or recognize individual zebrafish. However, classic methods used in fish ecology and aquaculture are generally difficult to apply to such small fish. Recently, various new tagging methods have been developed. This paper presents a first review of current identification and marking methods applied to zebrafish, from external observation methods (such as skin pattern recognition, fin clipping, scale regeneration, colour and transgenic methods) to the most advanced technological developments in electronic (low- and high- radio-frequencies PIT tags, microchip) and image analysis methods (video tracking). This review aims to help researchers and zebrafish facility managers select the identification method (ID) best adapted to their needs. The main characteristics of each ID method are examined (including detection range, durability, speed and repetitiveness, ID code combination, size dependence and ethical considerations), and their pros and cons are summarized in a decision table to help select the most appropriate option for a research or management program. Finally, contextual applications of these ID methods and future developments are discussed