Anticipation of cyclical resource availability in the red-footed tortoise (Chelonoidis carbonaria): Implications for seed dispersal.

Abstract

Many plant populations are dependent on animal-mediated seed dispersal; however, in the study of mutualistic processes, animals are generally thought of as unselective consumers. This approach is problematic as it does not consider the decisions of the foraging animals, and little attention is given to the cognitive processes that underpin these behaviors. One such process is the ability to predict fruit availability, as this would allow animals to direct their foraging towards productive food sources and would ensure rapid seed removal when fruits are ready to be eaten. This is particularly important for species that cannot move rapidly between resources, such as tortoises. This study investigated temporal (24-h cycle) and visual cues use during food anticipation in captive red-footed tortoise (Chelonoidis carbonaria), an important seed disperser in its natural environment. A significant increase in activity was observed in the hour immediately preceding food delivery, suggesting that the tortoises learned to predict the availability of food. Test trials, in which the visual and temporal cues were put in conflict or removed, revealed that the tortoises used both sources of information to predict food availability. Moreover, extinction trials, in which the tortoises did not have reliable temporal or visual cues prior to feeding, resulted in a rapid loss of anticipatory behavior. These findings provide insights into the cognitive processes that control anticipatory foraging behavior and, as such, have important implications for both animal and plant fitness, furthering our knowledge of mutualistic services such as seed dispersal.