Program & Abstract Book - EPFL Latsis Symposium 2009

EPFL Latsis Symposium 2009: Understanding Violence
S-22
48
February 11-13 2009
wi n n e r s , l o s e r s a n D b y s t a n D e r s : t h e
s t r u c t u r e o f D o m i n a n c e h i e r a r c h i e s
Dugatkin, Lee Alan
Department of Biology, University of Louisville, USA
Dominance hierarchies are a fundamental part of the social fabric of animals
that live in groups, and behavioral ecologists have sought to understand the
dynamics and stability of such dominance hierarchies. I present a family of
models that my colleagues and I have developed to examine how winner effects,
loser effects and bystander effects impact the structure and stability
of dominance hierarchies. We have found that when winner effects alone
are in play, a strict linear hierarchy emerges in which all individuals hold an
unambiguous rank and fights are common. When examining loser effects in
the absence of winner effects, a clear top-ranked individual always emerges,
but the rank of others in the group is unclear. In addition, when loser
effects are in play, interactions are primarily of the form “attack-retreat,”
wherein one animal opts to fight, but the other does not.