Presentation on theme: "Emily McHenry Biology 478 April 25, 2012 COLLECTIVE DECISION MAKING: SYNCHRONOUS MOVEMENT OF INDIVIDUALS IN GROUPS."— Presentation transcript:
Emily McHenry Biology 478 April 25, 2012 COLLECTIVE DECISION MAKING: SYNCHRONOUS MOVEMENT OF INDIVIDUALS IN GROUPS
WHAT IS COLLECTIVE BEHAVIOR? feature=related (Start at 3:37)
Collective animal behavior: the coordinated behavior of large groups of similar animals and the emergent properties of these groups (Couzin 2012). WHAT IS COLLECTIVE BEHAVIOR? worldhum.com
Flocks of birds Swarms of insects Schools of fish Herds of mammals EXAMPLES OF COLLECTIVE BEHAVIOR aquariumprosmn.com esa.orgdigital-photography-school.com
Increased foraging efficiency (Bazazi 2012) Energy efficiency (Tamm 1980) Aerodynamic and hydrodynamic benefits Predation avoidance Relies on selfish herd effect; increased group size results in lower chances of any one individual becoming a victim WHY DO ANIMALS MOVE SYNCHRONOUSLY?
There are 3 Distinct patterns of predation avoidance Vacuolization: where expansion results in a cavity forming around the predator Flash expansion: where individuals rapidly move away from the predator as it strikes Split effect where the group fragments Most common reason for aggregations, but not always beneficial! PREDATION AVOIDANCE
Most research has been done in two ways: 1.Filming groups and then frame- by-frame analyzing 2.Swarm simulating software STUDYING COLLECTIVE BEHAVIOR princeton.edu
SWARM SIMULATIONS GUkjC-69vaw Swarms are created following 3 fundamental rules : Separation: steer to avoid crowding or collisions Alignment: steer toward the average heading of groupmates Cohesion: steer to move toward the average position of local groupmates
Previously thought to be telepathic Utilizing senses Eyesight, pressure, hearing, etc. Monitoring position of neighbors Behavioral zones Repulsion Attraction Alignment based on relative position HOW DO ANIMALS MOVE SYNCHRONOUSLY?
Flocking Birds/Schooling Fish Democracy Quorum responses (Sumpter 2009) Insects No leader, forced march (Simpson 2006) Mammals Unknown DECISION MAKING IN THE GROUP
Potts, Wayne K "The chorus-line hypothesis of coordination in avian flocks." Nature 24: Simpson, Stephen J, Gregory A. Sword, Patrick D. Lorch, and Iain D. Couzin. "Cannibal Crickets on a Forced March for Protein and Salt." Proceedings of the National Academy of Sciences of the United States of America (2006): Bazazi, S. et al. (2012) Vortex formation and foraging in polyphonic spadefoot toad tadpoles. Behavioral Ecology and Sociobiology. March Tamm, Staffan. "Bird Orientation: Single Homing Pigeons Compared with Small Flocks." Behavioral Ecology and Sociobiology. 7.4 (1980): Tien, J Rubenstein, D. “Dynamics of fish shoals: Identifying key decision rules.” Evolutionary Ecology Research, No. 6. (2004), pp Ward, A.J.W, D.J.T Sumpter, I.D Couzin, P.J.B Hart, and J Krause. "Quorum Decision-Making Facilitates Information Transfer in Fish Shoals." Proceedings of the National Academy of Sciences of the United States of America (2008): Sumpter, D.J.T, and S.C Pratt. "Quorum Responses and Consensus Decision Making." Philosophical Transactions of the Royal Society B: Biological Sciences (2009): Couzin, I D, and J Krause. "Self-organization and Collective Behavior in Vertebrates." Advances in the Study of Behavior. 32 (2003): Couzin, I. D., J. Krause, R. James, G. D. Ruxton, and N. R. Franks Collective memory and spatial sorting in animal groups. Journal of Theoretical Biology 218: Caraco, T., S. Martindale, and H. R. Pulliam Flocking: advantages and disadvantages. Nature 285: WORKS CITED