Coupling lifespan and aging? The age at onset of body mass decline associates positively with sex-specific lifespan but negatively with environment-specific lifespan

Abstract

Coupling lifespan and aging? The age at onset of body mass decline associates positively with sex-specific lifespan but negatively with environment-specific lifespan.

Mosaic metabolic ageing: Basal and standard metabolic rate age in opposite directions and independent of environmental quality, sex or lifespan in a passerine

“…To 309 what extent and for what kind of traits this is the case however remains to be identified (Bansal 310 et al, 2015;Christensen et al, 2009;Williams, 1999). Indeed, in our study system we found little 311 evidence for such association: the environmental factors affecting lifespan did not affect the 312 ageing of metabolic traits or body mass (Briga et al 2019), and neither were rates of ageing higher 313 in shorter lived individuals. Apparently, (environmental) factors affecting lifespan can be distinct 314 from factors affecting ageing rate, which was also suggested for genetic factors (Burger and 315 Promislow 2006).…”

“…We applied a 2x2 70 design, independently manipulating foraging costs during development and in adulthood. This 71 manipulation shortened lifespan and decreased body mass, BMRm and SMRm in our experimental 72 population Briga et al 2019). In our experiment, 73 individuals experiencing high foraging costs during development and in adulthood (HH group) 74 lived on average six months (12%) shorter than all other groups.…”

“…Testing the HH group against all other experimental groups gave 218 supported this conclusion (ΔAICc>+13.5). Females lived on average two months shorter than 219 males (4%; Briga et al, 2019). However, sexes did not differ in their BMRm (ΔAICc=+4.7; Table 220 S2), in their BMRm response to the environmental manipulations (ΔAICc>+11.6; Table S2) or in 221 their BMRm ageing (ΔAICc>+19.2; Table S7).…”

Sex-specific body mass ageing trajectories in adult Asian elephants

“…We tested several within-individual ageing trajectories of increasing complexity (linear, quadratic, threshold, terminal models, figure S1) and selected the model with the lowest AICc. For threshold models (figure S1C), we followed the approaches previously developed in [4,27]. Briefly, we first identified the best fitting threshold age in a series of models, varying the threshold in the ‘Δage’ term between -35 to 22 years with intervals of 1Δage (=4.4 and 4.5 years for males and females respectively) and estimated the threshold and its confidence intervals using ±4 ΔAIC age range.…”

“…We tested a number of within-individual ageing trajectories of increasing complexity (linear, quadratic, threshold models, figure S1). To determine whether changes in body mass started at a certain threshold age (figure S1C), we followed the approaches previously developed in [4,29].…”