Behavioral variation in natural contests: integrating plasticity and personality

Abstract

Animals often interact aggressively when competing over limited resources. Aggressive decisions can be complex and may result from multiple sources of behavioral variation. The outcome of contests may be explained through contest theory and personality by considering conjointly plasticity and individual consistency. This integrative approach also allows investigating individual differences in responsiveness to environmental changes. Here, we observed multiple agonistic interactions occurring among eastern chipmunks (Tamias striatus) competing for food resources supplied at different distances from their burrows. Using an individual reaction norm approach, we found that the probability of winning a contest depended on an individual’s intrinsic characteristics (mass and age but not sex) but was also adjusted to characteristics of its opponents. Winning a contest also depended on extrinsic environmental characteristics, such as distance to the contestants’ burrows, but not the order of arrival at the feeding patch. We found consistent individual differences in the probability of winning, potentially related to differences in aggressiveness and territoriality. We also found that individuals differed in their plasticity level in response to changes in different characteristics of their social and physical environments. Plasticity, personality, and individual differences in responsiveness may thus all play a role in predicting contest outcome and in the evolution of animal contests.

Fighting ability, personality and melanin signalling in free-living Eurasian tree sparrows (Passer montanus)

“…If any such unmeasured trait is important in determining the relationship between exploratory behaviour and fighting ability (see e.g. , Dingemanse & de Goede, 2004 ; Couchoux et al, 2021 ), an association between the two could remain masked. Overall, the fact that we have not found a significant relationship between fighting ability and exploratory behaviour does not exclude that a correlation still exists between the two under certain scenarios.…”

“…For instance, in a handful of species chances of winning a fight are higher for males than for females ( e.g. , Richner, 1989 ; Briffa & Dallaway, 2007 ; but see Couchoux et al, 2021 ), or for adults than for juveniles ( e.g. , Richner, 1989 ; Couchoux et al, 2021 ).…”

“…, Richner, 1989 ; Briffa & Dallaway, 2007 ; but see Couchoux et al, 2021 ), or for adults than for juveniles ( e.g. , Richner, 1989 ; Couchoux et al, 2021 ). Also, larger individuals usually win more often than smaller ones ( e.g.…”

“…Also, larger individuals usually win more often than smaller ones ( e.g. , Richner, 1989 ; Lindström, 1992 ; Briffa, 2008 ; Chamorro-Florescano, Favila & Macías-Ordóñez, 2011 ; Rudin & Briffa, 2011 ; Couchoux et al, 2021 ). Also, fighting ability was found to be related to certain individual behavioural characteristics as well, like problem solving capacity (less competitive individuals are better problem-solvers; e.g.…”

Emergence of size-structured dominance hierarchies through size-dependent feedback

“…[ 17 ]) and mammals (e.g. [ 18 , 19 ]), including in species that habitually form long-term, dominance-structured groups (e.g. [ 20 ]).…”