Tandem running by foraging Pachycondyla striata workers in field conditions vary in response to food type, food distance, and environmental conditions

• Published in: Current zoology Vol. 67; no. 5; pp. 541 - 549
• Main Authors: Silva, Janiele Pereira, Valadares, Lohan, Vieira, Maria Eduarda Lima, Teseo, Serafino, Châline, Nicolas
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01-10-2021
• Subjects: Ants; Colonies; Decision-making; Environmental aspects; Environmental conditions; Environmental quality; Food; Food and nutrition; Food sources; Foraging; Foraging behavior; Humidity; Motivation; Pachycondyla striata; Protein sources; Relative humidity; Running; Social aspects; Special Column: Uncovering Variation in Social Insect Communication; Tandem running; Workers (insect caste); Zoological research; Brazil; social learning; flexibility; decision-making; emotional states; Ponerinae; collective behavior
• DOI: 10.1093/cz/zoab050
• EISSN: 2396-9814
• ISSN: 1674-5507

Abstract
Ants show collective and individual behavioral flexibility in their response to immediate context, choosing for example between different foraging strategies. In Pachycondyla striata, workers can forage solitarily or recruit and guide nestmates to larger food sources through tandem running. Although considered more ancestral and less efficient than pheromone trail-laying, this strategy is common especially in species with small colony size. What is not known is how the decision to recruit or follow varies according to the immediate context. That is, how fine adjustments in information transfer affect immediate foraging decisions at the colony level. Here, we studied individually marked workers and evaluated their foraging decisions when food items varied in nature (protein versus carbohydrate), size, and distance from the nest at different temperatures and humidity levels. Our results show that tandem run leaders and potential followers adjust their behavior according to a combination of external factors. While 84.2% of trips were solitary, most ants (81%) performed at least 1 tandem run. However, tandem runs were more frequent for nearby resources and at higher relative humidity. Interestingly, when food items were located far away, tandem runs were more successful when heading to protein sources (75%) compared with carbohydrate sources (42%). Our results suggest that the social information transfer between leaders and followers conveys more information than previously thought, and also relies on their experience and motivation.