Are animal personality, body condition, physiology and structural size integrated? A comparison of species, populations and sexes, and the value of study replication.

A major question in behavioural ecology is why behaviour, physiology and morphology are often integrated into syndromes. In great tits, Parus major, for example, explorative males are larger (vs. smaller) and leaner (vs.

Strong phenotypic trait correlations between mating partners do not result from assortative mating in wild great tits (Parus major).

There is considerable debate about the occurrence of assortative mating between phenotypic traits measured within natural populations. Meta-analyses have implied that assortative mating occurs generally in natural populations, but recent work indicates these conclusions largely result from biased data. Specifically, estimates of phenotypic correlations between mating partners do not solely result from nonrandom associations between individual-level traits of partners but also from other biological processes (joint phenotypic plasticity, indirect genetic effects), methodological practices (observer bias) and other unexplained residual correlations (e.

The association between personalities, alternative breeding strategies and reproductive success in dunnocks.

Although consistent between-individual differences in behaviour (i.e. animal personality) are ubiquitous in natural populations, relatively few studies have examined how personalities influence the formation of social relationships.

Dunnock social status correlates with sperm speed, but fast sperm does not always equal high fitness.

Sperm competition theory predicts that males should modulate sperm investment according to their social status. Sperm speed, one proxy of sperm quality, also influences the outcome of sperm competition because fast sperm cells may fertilize eggs before slow sperm cells. We evaluated whether the social status of males predicted their sperm speed in a wild population of dunnocks (Prunella modularis).

Dominance relationships and coalitionary aggression against conspecifics in female carrion crows.

Cooperation is a prevailing feature of many animal systems. Coalitionary aggression, where a group of individuals engages in coordinated behaviour to the detriment of conspecific targets, is a form of cooperation involving complex social interactions. To date, evidence has been dominated by studies in humans and other primates with a clear bias towards studies of male-male coalitions.

Personality-matching habitat choice, rather than behavioural plasticity, is a likely driver of a phenotype-environment covariance.

An emerging hypothesis of animal personality posits that animals choose the habitat that best fits their personality, and that the match between habitat and personality can facilitate population differentiation, and eventually speciation. However, behavioural plasticity and the adjustment of behaviours to new environments have been a classical explanation for such matching patterns. Using a population of dunnocks (), we empirically tested whether personality or behavioural plasticity is responsible for the non-random distribution of shy and bold individuals in a heterogeneous environment.