The impact of continuous variation in heritable personalities on
the social structure in the great tit (Parus major)
P.J. Drent
Netherlands Institute of Ecology (NIOO-KNAW), Heteren,
The Netherlands
Great tits of both sexes show continuous variation in consistent phenotipically
individual
differences in exploration of a standard new environment (a gradual variation
from fast to
slow explorer). Although the absolute values of repeated tests varied
with the year cycle,
the inter-individual differences persist across time. This exploration
score is phenotipically
correlated with many other behavioral traits related to coping with (environmental)
challenges (e.g. boldness, risk-taking, aggressiveness, routine-formation,
foraging patterns).
Bi-directional selection and crossings experiments using a cross fostering
design with
guest-pairs show that these different behavioral traits are strongly genetically
correlated.
This all indicates a more general behavioural syndrome or coping strategy
within the lifehistory
of the species, comparable with the variation in human personality.
Hand-reared and wild birds were used in an array of experiments to study
the impact of these personalities on the composition, structure and hierarchy
in winter flocks with a scrounger producer character. The dominant-submission
interactions between the members of a group were standard scored on and
around a feeding table. Males dominated females. Males with territorial
status and for females mating with a territorial male have the highest
position in the rank. In the hierarchy of territorial males the nearby
the territory the higher the position in rank and within that: faster
explorer dominated slower ones. In mixed groups of age and status classes
the time of presence and the personality determined the rank between non-territorial
males whereby in contrast to territorial birds long present slow explores
dominated fast ones. This is caused by impact of actions of (old) territorial
males on the non territorial juveniles that is different for the different
personalities.
Paper presented
at Measuring Behavior 2005
, 5th International Conference on Methods and Techniques
in Behavioral Research, 30 August - 2 September 2005, Wageningen, The
Netherlands.
© 2005 Noldus
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