Date Approved
2026
Degree Type
Open Access Thesis
Degree Name
Master of Science (MS)
Department or School
Biology
Committee Member
Cara Shillington, Ph.D
Committee Member
Katherine Greenwald, Ph.D.
Committee Member
Allen Kurta, Ph.D.
Abstract
Sexual dimorphism in longevity represents a striking example of natural selection favoring reproductive success over survival: in Colorado brown tarantulas (Aphonopelma hentzi), females live over two decades while males survive just months after reaching sexual maturity. I collected sexually mature males at three time points (August, September, October) across two years and quantified metabolic rates, locomotor performance, and survival under controlled laboratory conditions. This thesis comprises two articles examining complementary dimensions of that decline: metabolic senescence and locomotor performance. Open-flow respirometry revealed significant seasonal shifts: minimum metabolic rate increased through October, and metabolic scope peaked in September before declining. Survival differed strongly among cohorts, with October males living far fewer days than August males. Locomotor performance remained largely stable across the season. Together, these results demonstrate rapid, non-linear physiological senescence within a single reproductive season and support a trade-off framework linking mate-searching effort to accelerated male aging.
Recommended Citation
Poscente, Spencer, "Love in the fast lane: Rapid physiological senescence at sexual maturity in male Colorado Brown tarantulas (Aphonopelma hentzi)" (2026). Master's Theses and Doctoral Dissertations. 1350.
https://commons.emich.edu/theses/1350