Behavioral plasticity is not significantly associated with head volume in a wild Chestnut Thrush(Turdus rubrocanus) population

摘要

Background: The drivers of intraspecific variation in behavioral plasticity are poorly known. A widely held hypothesis is that brain size is positively correlated with behavioral plasticity.Methods: A total of 71 Chestnut Thrushes(Turdus rubrocanus) were caught in the wild population. We quantified behavior plasticity of activity of individuals measured in the same cage across two contexts(common and with a novel object stimulation), using a random regression analysis. We then investigated whether head volume(a proxy for brain size) was associated with behavioral plasticity in activity level using Spearman rank-order correlation.Results: We found no significant evidence that activity plasticity was associated with relative head volume. There was no sex difference in head volume or in variance in head volume.Conclusions: We speculate that the absence of an association between brain volume and activity behavior plasticity may result from the inaccuracy of using external skull measurements to estimate brain size, or from a particular part of the brain being responsible for plasticity in activity level.