Abstract:
One of the most prominent life-history trade-offs involves the cost of reproduction. Oxidative stress has been proposed
to be involved in this trade-off and has been associated with reduced life span. There is currently an unclear
relationship between oxidative cost and the reproduction-longevity trade-off. The current study, using a non-lethal
and minimally invasive (only a single blood sample and no euthanasia) method, investigated whether an oxidative
cost (oxidative stress) to reproduction would be apparent in two long-lived eusocial mole-rats, the naked mole-rat
(NMR), Heterocephalus glaber, and the Damaraland mole-rat (DMR), Fukomys damarensis, where breeding colony
members live longer than non-breeder conspecifics. We measured the direct redox balance in plasma by measuring
the oxidative stress index (OSI) based on the ratio of total oxidant status and total antioxidant activity in breeders and
non-breeders of both sexes, in the two species. NMR had significantly higher OSI between breeders and non-breeders
of each sex, whereas DMR showed no significant differences except for total antioxidant capacity (TAC). The mode of
reproductive suppression and the degree of reproductive investment in NMR may explain to some degree the redox
balance difference between breeders and non-breeders. DMR show minimal physiological changes between breeders
and non-breeders except for the mode of reproduction, which may explain some variations in TAC and TOS values,
but similar OSI between breeders and non-breeders.
Description:
SUPPLEMENTARY MATERIAL : Tables S1 and S2. Sample details and respective TOS (total oxidant status), TAC (total antioxidant capacity) and OSI (oxidative stress index) for Naked mole-rats and for Damaraland mole-rats. NBF: non-breeding females, NBM: non-breeding males, BM: breeding males, BF: breeding females.
