Abstract:
Oxidative stress has been implicated as both a physiological cost of reproduction and a driving force on an animal’s lifespan.
Since increased reproductive effort is generally linked with a reduction in survival, it has been proposed that oxidative stress
may influence this relationship. Support for this hypothesis is inconsistent, but this may, in part, be due to the type of
tissues that have been analyzed. In Damaraland mole-rats the sole reproducing female in the colony is also the longest
lived. Therefore, if oxidative stress does impact the trade-off between reproduction and survival in general, this species may
possess some form of enhanced defense. We assessed this relationship by comparing markers of oxidative damage
(malondialdehyde, MDA; protein carbonyls, PC) and antioxidants (total antioxidant capacity, TAC; superoxide dismutase,
SOD) in various tissues including plasma, erythrocytes, heart, liver, kidney and skeletal muscle between wild-caught
reproductive and non-reproductive female Damaraland mole-rats. Reproductive females exhibited significantly lower levels
of PC across all tissues, and lower levels of MDA in heart, kidney and liver relative to non-reproductive females. Levels of TAC
and SOD did not differ significantly according to reproductive state. The reduction in oxidative damage in breeding females
may be attributable to the unusual social structure of this species, as similar relationships have been observed between
reproductive and non-reproductive eusocial insects.
