INFLUENCE OF CONSPECIFIC ATTRACTION ON THE SPATIAL-DISTRIBUTION OF LEARNING FORAGERS IN A PATCHY HABITAT

1. Individuals in many social species are attracted to feeding conspec ifics. The profitability of conspecific attraction is negatively frequ ency-dependent and can be modelled as a producer-scrounger (PS) game f or which the ESS solution predicts some mixture of producer (no attrac tion) and scrounger (attraction) tactics in the population. Current mo dels for the spatial distribution of rate-maximizing foragers, which l earn the quality of habitats as they exploit patches, ignore the possi ble effect of conspecific attraction on the stable distribution of for agers. 2, We used simulations of a population with ESS levels of attra ction to investigate the effect of conspecific attraction on the spati al distribution of learning foragers which incur travel costs. In habi tats where patches depleted slowly, ESS levels of attraction helped fo ragers which experienced no interference reach the expected ideal free distribution (IFD) by facilitating aggregation to the richest patches . Large aggregations also occurred with interference and thus reduced the fit to the IFD, which in this case predicts a scatter of foragers across patches of varying quality. 3. In habitats where patches deplet ed rapidly, ESS levels of attraction prevented foragers from reaching the IFD, irrespective of interference levels. Foragers failed to learn habitat quality and thus often aggregated in poor patches, especially in large populations which depleted patches faster and had fewer oppo rtunities to learn quality. 4. Predictions of the model in habitats wh ere patches deplete slowly are supported by several studies. More work is needed for habitats where patches deplete more rapidly. We conclud e that conspecific attraction can have important, and often disruptive effects on spatial distributions.