Facing multiple information sources while foraging on successive patches: how does a parasitoid deal with experience?

Animals adjust their behaviour in response to changing environmental conditions. This form of plasticity can result from animals’ experience and their capacity to update information about their habitat. In the context of optimal foraging in patchy environments, animals may estimate profitability of patches from different cues to update their estimate of the profitability of the whole habitat. Updating may be achieved by weighting pieces of information obtained at different times. We studied how female parasitoids, Venturia canescens, weight different cues about each host patch profitability they successively encounter to adjust their foraging decisions accordingly. Our results show that parasitoids clearly perceived the profitability of the patches and that their foraging decisions were equally influenced by older and more recent foraging experience. We designed a second experiment to unravel, from three interdependent cues of patch profitability, which information source was mainly used to update the estimate of environmental profitability. The number of eggs laid in previously visited host patches seems to be an integrative cue of environmental profitability. We discuss the adaptive value of the weighting of successive pieces of information and the use of the different information sources in regard to the ecological context in which the wasps thrive.