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Weaker Bite Force in Elderly Nazca Boobies

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abstract
Detecting physiological decline in old age that underlies declines in survival and reproduction in a wild population can be challenging. This applies especially to long-lived species that require marking around birth in order to recognize elderly individuals perhaps decades later. Here, we used bite force of known-age, long-lived Nazca boobies (Sula granti) as a functional measure of muscle strength. Elderly Nazca boobies show declining survival and reproduction (senescence). Identifying muscle strength as a candidate physiological contributor to this decline, we predicted a parallel age-related decline in muscle strength from middle to old age. Data were collected from 349 nonbreeding adults using a force transducer during the breeding season in November 2017 on Isla Española, Galápagos. Both sexes showed the predicted drop in bite force in the second half of the lifespan. The decline began at a younger age in females, in parallel with sex-specific schedules of actuarial and reproductive senescence documented in an earlier study. Understanding which physiological traits show decline in old age contributes to an integrative portrait of the senescence process in wild animals.
subject
Bite force
Galapagos
Jaw muscle
Seabird
Senescence
contributor
Rebol, Erynn J. (author)
Anderson, David J (committee chair)
Anderson, Todd M (committee member)
Ashley-Ross, Miriam A (committee member)
Silman, Miles R (committee member)
date
2020-05-29T08:36:04Z (accessioned)
2020 (issued)
degree
Biology (discipline)
2021-05-28 (liftdate)
embargo
2021-05-28 (terms)
identifier
http://hdl.handle.net/10339/96833 (uri)
language
en (iso)
publisher
Wake Forest University
title
Weaker Bite Force in Elderly Nazca Boobies
type
Thesis

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