The questions about why and how senescence occurs in the wild are among the most pertinent ones in evolutionary ecology. Telomere length is a commonly used marker for aging, while other biomarkers of aging have received considerably less attention. Here we studied how another potent indicator of aging-skin pentosidine concentration-relates to age and blood telomere length in a long-lived seabird with well-documented reproductive senescence. We found no associations between telomere length, skin pentosidine and chronological age in male common gulls (Larus canus), aging from 2 to 30 years. However, the variance in telomere length was 4.6 times higher among the birds older than 13 years, which hints at relaxed selection on telomere length among the birds that have passed their prime age of reproduction. These results suggest that physiological and chronological ages may be largely uncoupled in our study system. Furthermore, our findings do not support a hypothesis about the presence of a common physiological factor (e.g., such as oxidative stress) that would cause covariation between two independent markers of aging.

No abstract

Development of a Minimally Invasive Sampling Technique to Estimate the Age of Living Birds Crissa K. Cooey Using pest species in initial studies of pentosidine (Ps) aging research for birds may be the catalyst to discovering more effective population control strategies for pest, invasive, and hard to manage birds. Pentosidine is an irreversible, stable, fluorescent, collagen cross-link, created through the Maillard reaction, which has been found to accumulate throughout the lifetime of an organism in various body parts such as skin, lens crystalline, and dura matter. Pentosidine assays are more accurate at determining the age of adult birds in comparison to plumage coloration, eye and mouth color, feather wear, and molt sequences due to the discovery that Ps accumulates with age in the skin of birds. Past studies, however, have only taken place on deceased birds. To be considered a more generally useful tool for wildlife management studies, a procedure to obtain skin samples from living birds is needed. The objective of this project was to develop a minimally invasive sampling technique to age live birds through Ps analysis by 1) determining if differences exist in Ps concentration between the breast and patagium of black vultures (Coragyps atratus), monk parakeets (Myiopsitta monachus), and double-crested cormorants (Phalacrocorax auritus), 2) determining if differences exist in Ps concentration of 6 mm 2 and 20 mm 2 skin samples, and 3) determining if healing rates differ between the breast and patagium and between wounds closed with tissue glue and wounds closed with sutures. Pentosidine concentrations were similar between the breast (x = 8.9 pmol/mg collagen, SE = 0.55) and patagium (x = 8.9 pmol/mg collagen, SE = 0.51) of black vultures (P = 0.97) as well as the breast (x = 11.2 pmol/mg collagen, SE = 1.10) and patagium (x = 10.6 pmol/mg collagen, SE = 1.10) of deceased double-crested cormorants (P = 0.10). Pentosidine, however, was significantly higher in the breast (x = 15.9 pmol/mg collagen, SE = 1.30) than the patagium (x = 11.5 pmol/mg collagen, SE = 1.10) of monk parakeets (P < 0.0001). The Ps concentration was marginally higher in 6 mm 2 skin samples (x = 12.6 pmol/mg collagen, SE = 1.19) when compared to 20 mm 2 skin samples (x = 11.3 pmol/mg collagen, SE = 1.23) of cormorants (P = 0.02). Four new age curves were developed for cormorants (our linear breast skin age curve, our curvilinear breast skin age curve, our linear patagial skin age curve, and our curvilinear patagial skin age curve) and compared to the original Fallon age curve. Age estimates and actual ages for cormorant breast and patagial skins were found to be similar when using our linear and curvilinear breast and patagial skin age curves, but there were significant differences between actual and estimated ages for breast and patagial skin when using the Fallon age curve (P <0.0001 and P <0.0001 respectively). The mean estimated ages for all 5 age curves were found to be accurate to within approximately 1½ years (17.4 months). For 6 mm 2...

2016-11-03T14:11:40

No abstract