Date of Award

Winter 12-11-2023

Document Type

Honors Thesis



First Advisor

Andrea Liebl

Second Advisor

Hugh Britten

Third Advisor

David Swanson


Telomeres, Cooperative Breeding, Helper Number, Developmental Environment

Subject Categories



Telomeres are chromosomal elements that protect and maintain genes as DNA replicates in many organisms. As individuals age and DNA replicates, telomeres often shorten; thus, telomere length often corresponds with an individual’s lifespan, and early-life decreases in telomere length can be predictive of longevity. Here, I investigated the relationship between telomere length and developmental environment in a cooperatively breeding species, the chestnut-crowned babbler (Pomatostomus ruficeps; CCB). Cooperative species are unique, as some individuals give up their own breeding opportunities to help rear the offspring of others; further, cooperative breeding systems generate considerably more variation in adult carers, which makes parental care highly variable, even within a species. Using qPCR, I measured telomere lengths in the DNA of CCB offspring. I found that hatchlings born after increased rainfall had longer telomeres than those born after decreased rainfall, possibly due to the increased food availability induced by rain. Further, fledglings born with four or more helpers had shorter telomeres than those born with less than four helpers, potentially due to increased resource competition in larger groups. Interestingly, differences in telomere length were driven more by helper number than by brood size indicating the effect is driven by adult care rather than sibling competition. The results of this study present a more detailed view of the relationship between telomere length and developmental environment in a cooperatively breeding species. Additionally, these results provide insight into telomere lengths in other cooperative and non-cooperative species alike, as all species are susceptible to environmental stressors during development.

Included in

Biology Commons



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