Exercise training has morph-specific effects on telomere, body condition and growth dynamics in a color-polymorphic lizard

Alternative reproductive tactics (ARTs) are correlated suites of sexually
selected traits that are likely to impose differential physiological costs
on different individuals. While moderate activity might be beneficial,
animals living in the wild often work at the margins of their resources
and performance limits. Individuals using ARTs may have divergent
capacities for activity. When pushed beyond their respective capacities,
they may experience condition loss, oxidative stress, and molecular damage
that must be repaired with limited resources. We used the Australian
painted dragon lizard that exhibits color-polymorphism as a model to
experimentally test the effect of exercise on body condition, growth,
reactive oxygen species (ROS), and telomere dynamics, a potential marker
of stress and aging and a correlate of longevity. For most males, ROS
tended to be lower with greater exercise; however, males with yellow
throat patches, or bibs, had higher ROS than non-bibbed males. At the
highest level of exercise, bibbed males exhibited telomere loss, while
non-bibbed males gained telomere length; the opposite pattern was observed
in the no-exercise controls. Growth was positively related to food intake
but negatively correlated with telomere length at the end of the
experiment. Body condition was not related to food intake but was
positively correlated with increases in telomere length. These results,
along with our previous work, suggest that aggressive, territory holding,
bibbed males suffer physiological costs that may reduce longevity compared
to non-bibbed males with superior postcopulatory traits.