Social foraging in Bufo americanus tadpoles

Animals can find food using information from the food itself or from conspecifics that are also looking for food. Social information can be actively communicated or based on unavoidable by-products of feeding activities. We present three experiments that explore the relative importance of odour gradients and social information as Bufo americanus tadpoles locate food sources. In the first experiment, tadpoles rapidly aggregated at food patches and discriminated between the qualities of two food patches spaced 15 cm apart in the field. In a second experiment, the initial presence of tadpoles at one food patch enhanced aggregation for 1 h, compared to an identical food patch without tadpoles spaced 114 cm apart. In a third experiment, the time required to initial contact with a single food patch did not change over a 16-fold range of food concentration, suggesting that B. americanus tadpoles have a limited ability to locate food from a distance using information from the food itself. Finding food and discriminating food patch quality from a distance is probably a major adaptive advantage of sociality in B. americanus tadpoles, although the presence or absence of active signalling remains to be determined.