Main Article Content

Transporting food from production centers to consumption centers is a challenge for densely populated societies. To avoid delays, the trail system must be efficient and the behavior of the transporters must reduce the probability of collisions. This work, describes how Leaf-Cutting Ants (LCA) solve these dilemmas by optimizing their trail design and performing behaviors that avoid bottlenecks and delays. On the one hand, the LCA build trails wide
enough to avoid traffic jams at times of peak foraging activity. Also, at the bifurcation points, the sum of the branching trail widths is always higher than the width of the precedent trunk
trail. Finally, LCA builds their branching trails with angles that reduce the maintenance cost of the new trail sector or of the total trail length, depending on which factor is more limiting. On the other hand, LCA shows a range of behaviors that avoid delays: minima workers can travel on the leaf fragments thereby reducing flux density, unloaded workers remove obstacles from the trail, ants carry extra-large loads mainly during situations of low traffic, ants maintain their lane when turning, and foragers show priority rules during jam situations. These examples illustrate how ants, using simple behavioral rules that arise from positive interactions among individuals, can solve complex problems such as traffic regulation.

Farji-Brener, A. G. (2021). How to deal with the disadvantages of living in dense societies: traffic rules in leaf-cutting ants. Revista Colombiana De Entomología, 47(2).

ALMA, A. M.; FARJI‐BRENER, A. G.; ELIZALDE, L. 2020. With a little help from my friends: Individual and collaborative performance during trail clearing in leaf‐cutting ants. Biotropica

(3): 554-562.

BLACKLEDGE, T. A.; ELIASON, C. M. 2007. Functionally independent components of prey capture are architecturally constrained in spider orb webs. Biology Letters 3 (5): 456-458.

BRUCE, A. I.; CZACZKES, T. J.; BURD, M. 2017. Tall trails: ants resolve an asymmetry of information and capacity in collective maintenance of infrastructure. Animal Behavior 127: 179-185.

BURD, M.; D. ARCHER; N. ARANWELA; STRADLING, D. J. 2002. Traffic dynamics of the leaf-cutting ant Atta cephalotes. The American Naturalist 159 (3): 283-293. https://doi.


BURD, M. 2006. Ecological consequences of traffic organization in ant societies. Physica A: Statistical Mechanics and its Applications 372 (1): 124-131.

CIBILS-MARTINA, L.; ELIZALDE, L.; FARJI-BRENER, A. G. 2017. Traffic rules around the corner: walking of leaf-cutting ants at branching points in trunk trails. Insectes Sociaux 64 (4):


CLAES, R.; HOLVOET, T. 2012. Cooperative ant colony optimization in traffic route calculations. In Advances on Practical Applications of Agents and Multi-Agent Systems (pp. 23-34).

Springer, Berlin, Heidelberg.

DAWKINS, R. 1982. The extended phenotype (Vol. 8). Oxford University Press. New York, 440 p.

DOSSUTOUR, A.; BESHERS, S.; DENEUBOURG, J. L.; FOURCASSIÉ, V. 2007. Crowding increases foraging efficiency in the leaf-cutting ant Atta colombica. Insectes Sociaux 54 (2): 158-165.

DUSSUTOUR, A.; BESHERS, S.; DENEUBOURG, J. L.; FOURCASSIE, V. 2009. Priority rules govern the organization of traffic on foraging trails under crowding conditions in the leaf-cutting ant Atta colombica. Journal of Experimental Biology 212 (4): 499-505.

FARJI‐BRENER, A. G.; BARRANTES, G.; LAVERDE, O.; FIERRO‐CALDERÓN, K.; BASCOPÉ, F.; LÓPEZ, A. 2007. Fallen branches as part of leaf‐cutting ant trails: their role in resource discovery and leaf transport rates in Atta cephalotes. Biotropica 39 (2): 211-215.

FARJI-BRENER, A.G.; CARVAJAL, D.; GEI, M. G.; OLANO, J.; SÁNCHEZ, J. D. 2008. Direct and indirect effects of soil structure on the density of an antlion larva in a tropical dry forest.

Ecological Entomology 33 (2): 183-188.

FARJI-BRENER, A. G.; AMADOR-VARGAS, S.; CHINCHILLA, F.; ESCOBAR, S.; CABRERA, S.; HERRERA, M. I.; SANDOVAL, C.. 2010a. Information transfer in head-on encounters between leaf-cutting ant workers: food, trail condition or orientation cues? Animal Behavior 79 (2): 343-349.

FARJI‐BRENER, A. G.; CHINCHILLA, F. A.; RIFKIN, S.; SÁNCHEZ CUERVO, A. M.; TRIANA, E; QUIROGA, V; GIRALDO, P. 2010b. The ‘truck‐driver’ effect in leaf‐cutting ants: how individual load influences the walking speed of nest‐mates. Physiological Entomology 36 (2): 128-134.

FARJI-BRENER, A. G.; MORUETA-HOLME, N.; CHINCHILLA, F.; WILLINK, B.; OCAMPO, N.; BRUNER, G. 2012. Leaf-cutting ants as road engineers: the width of trails at branching points in Atta cephalotes. Insectes sociaux 59 (3): 389-394.

FARJI-BRENER, A. G.; CHINCHILLA, F.; UMAÑA, M. N.; OCASIO-TORRES, M. E.; CHAUTA-MELLIZO, A.; ACOSTA-ROJAS, D.; MARINARO, S.; DE TORRES CURTH, M.; AMADOR-VARGAS, S. 2015. Branching angles reflect a trade‐off between reducing trail maintenance costs or travel distances in leaf‐cutting ants. Ecology 96 (2): 510-517.

FARJI-BRENER, A. G.; AMADOR-VARGAS, S. 2020. Plasticity in extended phenotypes: how the antlion Myrmeleon crudelis adjusts the pit traps depending on biotic and abiotic conditions.

Israel Journal of Ecology and Evolution, 66 (1-2): 41-47.

FORUCASIÉ V.; DUSSUTOUR A.; DENEUBOURG, J. L. 2010. Ant traffic rules. Journal of Experimental Biology 213 (14): 2357-2363.

HASTENREITER, I. N.; LOPES, J. F. S.; DA SILVA CAMARGO, R.; FORTI, L. C. 2018. Avoiding traffic jams: Hitchhiking behavior as a strategy to reduce ant workers’ traffic on the foraging

trail. Behavioral processes 157: 54-58.

HÖLLDOBLER, B.; WILSON, E. O. 2010. The leafcutter ants: civilization by instinct. WW Norton & Company. New York, London, 192 p.

JABBARPOUR, M. R.; MALAKOOTI, H.; NOOR, R. M.; ANUAR, N. B.; KHAMIS, N. 2014. Ant colony optimization for vehicle traffic systems: applications and challenges. International Journal of Bio-Inspired Computation 6 (1): 32-56.

NAKATA, K. 2012. Plasticity in an extended phenotype and reversed up-down asymmetry of spider orb webs. Animal Behavior 83 (3): 821-826.

LOMÁSCOLO, S.; FARJI-BRENER, A. G. 2001. Adaptive shortterm changes in pit design by antlion larvae (Myrmeleon sp.) in response to different prey conditions. Ethology, Ecology and

Evolution 13 (4): 393-397.

PEREYRA, M.; FARJI-BRENER, A. G. 2020. Traffic restrictions for heavy vehicles: Leaf-cutting ants avoid extra-large loads when the foraging flow is high. Behavioral Processes 170: 104014. PETERS, K.; JOHANSSON, A.; DUSSUTOUR, A.; HELBING, D. 2006. Analytical and numerical investigation of ant behavior under crowded conditions. Advances in Complex Systems 9 (4): 337-352. RODRÍGUEZ‐PLANES, L. I.; FARJI‐BRENER, A. G. 2019. Extended phenotypes and foraging restrictions: ant nest entrances and resource ingress in leaf‐cutting ants. Biotropica 51 (2): 178-185.

SENDOYA, S.; SILVA, P. D.; FARJI-BRENER, A. G. 2014. Does inundation risk affect leaf-cutting ant distribution? A study along a topographic gradient of a Costa Rican tropical wet forest. Journal of Tropical Ecology 30 (1): 89-92.

SILVA, P.; BIEBER, A. G. D.; KNOCH, T. A.; TABARELLI, M.; LEAL, I. R.; WIRTH, R. 2013. Foraging in highly dynamic environments: Leaf-cutting ants adjust foraging trail networks to pioneer plant availability. Entomologia Experimentalis et Applicata 147 (2): 110-119. STONE, G. N.; COOK, J. M. 1998. The structure of cynipid oak galls: patterns in the evolution of an extended phenotype. Proceedings of the Royal Society of London. Series B: Biological Sciences 265 (1400): 979-988.


TURNER, J. S. 2000. The extended organism: the physiology of animal-built structures. Harvard University Press. Cambrige, UK, 256 p.

ZACHARIAH, N.; SINGH, S.; MURTHY, T. G.; BORGES, R. M. 2020. Bi-layered architecture facilitates high strength and ventilation in nest mounds of fungus-farming termites. Scientific

Reports 10 (1): 131157.


Download data is not yet available.