Information gleaned and former patch quality determine foraging behavior of parasitic wasps
Résumé
A good estimate of patch quality is of prime importance for a randomly searching forager with limited longevity or fecundity. The forager can perceive cues related to the presence of resource on arrival in a patch and estimates its quality relatively to previous patches. This prior estimate can then be updated through sampling in the patch. However, these 3 sources of information have never been manipulated independently in the same experiment to quantify the effect of each one on foraging behavior. Here, we report experiments highlighting the mechanism by which the braconid Asobara tabida, a parasitoid wasp laying eggs in Drosophila larvae, uses information both gleaned from the previous patch visited and obtained on arrival in the next one, to estimate the quality of the latter and to behave accordingly. We disentangled the effects of the prior estimate of patch qualitymade on arrival in the patch and the effect of sampling in the patch on the foraging behavior of the parasitoid. We show that information gleaned by A. tabida from a previously visited patch plays a strong role in the response to both chemical cues and oviposition events by parasitoid when exploiting a patch. The information process highlighted in the present study is consistent with the Bayesian-like decision-making, which is suspected in parasitoids, bumblebees, and humans. Moreover, motivation to stay in the patch is likely to be tuned to the forager's experience. Key words: Bayesian updating, decision, making, optimal foraging behavior, patch quality estimate.