emily mchenry biology 478 april 25, 2012 collective decision making: synchronous movement of...
TRANSCRIPT
Emily McHenry
Biology 478
April 25, 2012
COLLECTIVE DECISION MAKING:
SYNCHRONOUS MOVEMENT OF
INDIVIDUALS IN GROUPS
WHAT IS COLLECTIVE BEHAVIOR?
http://www.youtube.com/watch?v=Ua2quxUDyRk&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 fi sh
Herds of mammals
EXAMPLES OF COLLECTIVE BEHAVIOR
aquariumprosmn.com
esa.orgdigital-photography-school.com
Increased foraging effi ciency (Bazazi 2012)
Energy effi ciency (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! http://www.youtube.com/watch?v=XzZhSl_00pI&feature=related
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
http://www.youtube.com/watch?v=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
QUESTIONS?
Potts, Wayne K. 1984. "The chorus-line hypothesis of coordination in avian flocks." Nature 24: 344-345.
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. 103.11
(2006): 4152-4156.
Bazazi, S. et al. (2012) Vortex formation and foraging in polyphonic spadefoot toad tadpoles. Behavioral Ecology
and Sociobiology. March 2012.
Tamm, Staff an. "Bird Orientation: Single Homing Pigeons Compared with Small Flocks."
Behavioral Ecology and Sociobiology . 7.4 (1980): 319-322.
Tien, J Rubenstein, D. “Dynamics of fi sh shoals: Identifying key decision rules.” Evolutionary
Ecology Research, No. 6. (2004), pp. 555-565
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 . 105.19 (2008): 6948-6953.
Sumpter, D.J.T, and S.C Pratt. "Quorum Responses and Consensus Decision Making."
Philosophical Transactions of the Royal Society B: Biological Sciences . 364.1518 (2009): 743-
753.
Couzin, I D, and J Krause. "Self-organization and Collective Behavior in Vertebrates." Advances in the Study of
Behavior. 32 (2003): 1-75.
Couzin, I. D., J. Krause, R. James, G. D. Ruxton, and N. R. Franks. 2002. Collective memory and spatial sorting in
animal groups. Journal of Theoretical Biology 218: 1-11.
Caraco, T., S. Martindale, and H. R. Pulliam. 1980. Flocking: advantages and disadvantages. Nature 285: 400-401.
WORKS CITED