FARJI-BRENER Alejandro Gustavo
congresos y reuniones científicas
¿Remover o no remover obstáculos? costos y beneficios del mantenimiento de senderos de forrajeo en las hormigas cortadoras de hojas
Congreso; I Reunión de Biología del Comportamiento del Cono Sur; 2017
When the development of one activity is interrupted by a situation (i.e., when a problem comes up), social organisms must decide whether the problem is resolved or not, and how it is resolved. Considering that these decisions affect the fitness, organisms should choose the option that maximizes cost-benefit balance. Our aim was to evaluate what factors influence the decision to remove an obstacle by leaf-cutting ants and how costs and benefits of removal determine the number of ants removing. We placed obstacles of different sizes, in low and high ant fluxes in 10 nests of Atta sexdens. We measured the initial ant flux (without obstacles), the ant flux with obstacles, if there was or not removal, the number of ants removing and the removal time. We estimated the cost as the proportional reduction in ant flux (i.e., (〖Flux〗_Initial-〖Flux〗_Obstacle)/〖Flux〗_Initial ). We found that the cost increased with the obstacle size and the ant flux; and the probability of removing increased with this cost. In addition, the number of ants removing increased with the obstacle size, but decreased when the ant flux was high. This suggests that the number of ants removing depends on the problem´s difficulty (i.e., as obstacle size increases, the resistance to traction increases making removal harder) and the problem´s context (i.e., the interference between cleaners and foragers). Finally, the removal time increased with the number of ants removing, suggesting that workers attending a problem might interfere between one another. This work highlights that both intrinsic and extrinsic characteristics determine when and how a problem is resolved; and that the number of individuals participating in the resolution is affected by individual limitations and interactions among individuals