0000000000954336
AUTHOR
Simon Fellous
Condition-dependent effects of corticosterone on a carotenoid-based begging signal in house sparrows
International audience; Begging is a complex display involving a variety of different visual and auditory signals. Parents are thought to use these signals to adjust their investment in food provisioning. The mechanisms that ensure the honesty of begging displays as indicators of need have been recently investigated. It has been shown that levels of corticosterone (Cort), the hormone released during the stress response, increase during food shortage and are associated with an increased begging rate. In a recent study in house sparrows, although exogenous Cort increased begging rate, parents did not accordingly adjust their provisioning rate. Here, we tested the hypothesis that Cort might af…
Quorum Sensing and Density-Dependent Dispersal in an Aquatic Model System
International audience; Many organisms use cues to decide whether to disperse or not, especially those related to the composition of their environment. Dispersal hence sometimes depends on population density, which can be important for the dynamics and evolution of subdivided populations. But very little is known about the factors that organisms use to inform their dispersal decision. We investigated the cues underlying density-dependent dispersal in interconnected microcosms of the freshwater protozoan Paramecium caudatum. In two experiments, we manipulated (i) the number of cells per microcosm and (ii) the origin of their culture medium (supernatant from high-or low-density populations). …