Social foraging in the lizard Ameiva corax

Abstract

The diet of the lizard Ameiva corax includes bird eggs and fruit, which are items that represent more food than a single individual typically consumes; lizards often congregate at these large food items. We examined the extent to which lizards aggregate and to which locating food might be facilitated by social factors. During surveys, individual A. corax were most commonly seen in association with other conspecifics, sometimes as many as seven. Experiments indicated that lizards were recruited to noteworthy items in the environment (fruit or a novel nonfood object) and that recruitment to food was greater than to a novel, nonedible object. Use of visual displays varied with experimental conditions; aggressive displays were not used by animals visiting nonfood objects or abundant food but were observed when food was moderately limited. A nonaggressive display, which may signal the presence of food and invite others to join, was most commonly used by lizards at food and decreased in frequency as the number of lizards present increased. Their pattern of aggregation and use of behavioral displays demonstrate social foraging in A. corax; the potential role of social networks merits further investigation.