Data from: Individual variation in the oxidative costs of personality traits

1.‘Personality traits’ are behavioural differences between individuals
that are stable within individuals. Different combinations of personality
traits can correlate with fitness variation but the mechanisms remain
unclear. There is the suggestion that personality reflects variation in
physiology. For example, ‘fast’ (bold, active, fast exploring) individuals
are predicted to maintain a higher metabolic rate than ‘slow’ animals. A
raised metabolic rate can result in a proliferation of reactive oxygen
species (ROS) which, if unchecked, cause oxidative stress. Thus, the
‘extended pace of life theory’ predicts that ‘fast’ individuals will pay
higher oxidative costs than ‘slow’ ones. Alternatively, stress hormones,
which are often relatively high in ‘slow’ individuals, can also cause
proliferation of ROS and subsequent oxidative damage. Here, we assessed
co-variation between personality and oxidative profile in wild blue tits.
2.The personality traits neophobia (latency to approach food near novel
objects), activity level in a novel environment and exploratory tendency
(controlling for differences in activity) assayed in captivity were
repeatable within individuals but were uncorrelated with each other.
Reactive oxygen metabolites (ROMs an index of pro-oxidant status) and OXY
(antioxidant capacity) were also uncorrelated with each other and did not
vary with age or sex. Blood sampling birds within three minutes of capture
from their familiar cage versus after 15 minutes of exposure to a
standardised stressor did not affect ROMs or OXY. 3.Wintering blue tits
that were both highly neophobic and exploratory had low OXY defences and
individuals that showed low neophobia and low exploration had high OXY
defences. Variation in ROMs was not explained by any personality trait.
High exploratory tendency also correlated with a reduction in body
condition in captivity, but body condition did not predict ROMs or OXY.
Activity level in the exploration trial did not vary with oxidative
profile or change in body condition. 4.Personality types differed in
antioxidant defences, and it was the combination of an individual's
personality traits that proved important. ROS production and antioxidant
defences will vary due to many processes e.g. resource allocation, not
just metabolic rate and stress responsiveness. Consequently, the costs of
personality traits and thus the predictions regarding fitness are complex.
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