Telomere dynamics in a lizard with morph-specific reproductive investment and self-maintenance

Telomeres in human fibroblasts shorten progressively during in vitro culturing and trigger replicative senescence. Furthermore, shortened telomeres can be used as biomarkers of disease. These observations have led to the suggestion that telomere dynamics may also be associated with viability and selection for life history variation in non-human taxa. Model systems to examine this suggestion would particularly benefit from the coexistence of multiple phenotypes within the same species with different life history trade-offs, since those could be compared in terms of telomere characteristics. This scenario also provokes the classic question of why one morph does not have marginally higher fitness and replaces the others. One explanation is that different morphs have different reproductive tactics with equal relative fitness. In Australian painted dragons (Ctenophorus pictus), males differ in head color, the presence or absence of a gular bib, and reproductive expenditure. Red males out-compete yellow males in dominance contests, while yellow males copulate quickly and have higher success in sperm competition than red males. Males with bibs better defend partners against rival matings, at the cost of loss of body condition. We show that yellow-headed and bib-less males have longer telomeres than red, blue and bibbed males, suggesting that telomere length is positively associated with higher investment into self-maintenance and less reproductive expenditure.