The effects of costly telomere maintenance on lifespan-reproductive tradeoffs in sand lizards

Telomeres are DNA-protein structures that primarily protect chromosomes
and serve multiple functions of gene regulation. When cells divide,
telomeres shorten and their main repair system in ectotherms - telomerase
– replaces lost nucleotide complexes ((T2AG3)n in vertebrates). It remains
a challenge to experimentally investigate resource requirements for
telomere maintenance and its effects on lifespan-reproductive tradeoffs in
the wild. In sand lizards (Lacerta agilis), we show that higher female
investments into reproduction result in corresponding shortening of
telomeres and that males have less frequent and less profound telomere
shortening than females; a contributing factor to this may be males’
higher telomerase levels. To manipulate resource access for telomere
maintenance, we exploit a pseudo-experimental opportunity to analyze
‘onboard’ resources long-term using lizards that drop their tails with fat
and nutrient deposits when attacked by predators. Females with fewer
resources regrow tails less often and less profoundly elongate telomeres.
Adult lizards with the most TL elongation live the longest, females with
the highest lifetime reproductive success shorten telomeres the most,
whereas males with the most telomere elongation have the highest lifetime
reproductive success. This suggests ongoing evolution of
resource-constrained telomere maintenance.