Skip to main content

Research Repository

Advanced Search

Reactive stress-coping styles show more variable reproductive expenditure and fitness outcomes

Twiss, Sean D.; Shuert, Courtney R.; Brannan, Naomi; Bishop, Amanda M.; Pomeroy, Patrick. P.

Reactive stress-coping styles show more variable reproductive expenditure and fitness outcomes Thumbnail


Courtney R. Shuert

Naomi Brannan

Amanda M. Bishop

Patrick. P. Pomeroy


Stress-coping styles dictate how individuals react to stimuli and can be measured by the integrative physiological parameter of resting heart-rate variability (HRV); low resting HRV indicating proactive coping styles, while high resting HRV typifies reactive individuals. Over 5 successive breeding seasons we measured resting HRV of 57 lactating grey seals. Mothers showed consistent individual differences in resting HRV across years. We asked whether proactive and reactive mothers differed in their patterns of maternal expenditure and short-term fitness outcomes within seasons, using maternal daily mass loss rate to indicate expenditure, and pup daily mass gain to indicate within season fitness outcomes. We found no difference in average rates of maternal daily mass loss or pup daily mass gain between proactive and reactive mothers. However, reactive mothers deviated more from the sample mean for maternal daily mass and pup daily mass gain than proactive mothers. Thus, while proactive mothers exhibit average expenditure strategies with average outcomes, expenditure varies much more among reactive mothers with more variable outcomes. Overall, however, mean fitness was equal across coping styles, providing a mechanism for maintaining coping style diversity within populations. Variability in reactive mothers’ expenditures and success is likely a product of their attempts to match phenotype to prevailing environmental conditions, achieved with varying degrees of success.

Journal Article Type Article
Acceptance Date May 22, 2020
Online Publication Date Jun 12, 2020
Publication Date 2020
Deposit Date Jun 12, 2020
Publicly Available Date Jun 12, 2020
Journal Scientific Reports
Publisher Nature Research
Peer Reviewed Peer Reviewed
Volume 10
Issue 1
Article Number 9550
Public URL


Published Journal Article (1.8 Mb)

Publisher Licence URL

Copyright Statement
This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit

You might also like

Downloadable Citations