A fixed agreement—consequences of brood size manipulation on alternation in blue tits

Recent studies have proposed that conditional cooperation may resolve sexual conflict over the amount of care provided by each parent. Such conditional cooperation may allow parents to equalize their investment by alternating their provisioning visits. This alternated pattern of male and female visi...

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Main Authors: Maaike Griffioen, Wendt Müller, Arne Iserbyt
Format: Article
Language:English
Published: PeerJ Inc. 2019-04-01
Series:PeerJ
Subjects:
Online Access:https://peerj.com/articles/6826.pdf
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author Maaike Griffioen
Wendt Müller
Arne Iserbyt
author_facet Maaike Griffioen
Wendt Müller
Arne Iserbyt
author_sort Maaike Griffioen
collection DOAJ
description Recent studies have proposed that conditional cooperation may resolve sexual conflict over the amount of care provided by each parent. Such conditional cooperation may allow parents to equalize their investment by alternating their provisioning visits. This alternated pattern of male and female visits, that is, alternation, is thought to stimulate each other’s investment leading to higher levels of provisioning and potential benefits for offspring development. However, experimental studies testing the role of alternation as an adaptive parental strategy to negotiate the level of investment are still absent. Therefore, we manipulated blue tit (Cyanistes caeruleus) parents by temporarily changing their brood sizes to induce changes in demand and thus visit rates. Parents were expected to visit more—assuming that prey sizes were constant—and alternate at higher levels when confronted with an enlarged brood given the greater potential for sexual conflict. In contrast, in reduced broods visit rates and alternation may become lower due to the smaller investment that is needed for reduced broods. We show that the level of alternation did not differ in response to the manipulated brood sizes, despite a directional change in visit rates for enlarged and reduced broods as expected. Nestlings did not benefit from high levels of alternation as no effects on nestling mass gain were present in either of the different manipulations. These findings indicate that alternation does not serve as a mechanism to motivate each other to feed at higher rates. Parents hence appeared to be inflexible in their level of alternation. We therefore suggest that the level of alternation might reflect a fixed agreement about the relative investment by each of the caring parents.
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spelling doaj.art-c3a920c034f0478baa1f3f55d861090c2023-12-03T09:31:00ZengPeerJ Inc.PeerJ2167-83592019-04-017e682610.7717/peerj.6826A fixed agreement—consequences of brood size manipulation on alternation in blue titsMaaike GriffioenWendt MüllerArne IserbytRecent studies have proposed that conditional cooperation may resolve sexual conflict over the amount of care provided by each parent. Such conditional cooperation may allow parents to equalize their investment by alternating their provisioning visits. This alternated pattern of male and female visits, that is, alternation, is thought to stimulate each other’s investment leading to higher levels of provisioning and potential benefits for offspring development. However, experimental studies testing the role of alternation as an adaptive parental strategy to negotiate the level of investment are still absent. Therefore, we manipulated blue tit (Cyanistes caeruleus) parents by temporarily changing their brood sizes to induce changes in demand and thus visit rates. Parents were expected to visit more—assuming that prey sizes were constant—and alternate at higher levels when confronted with an enlarged brood given the greater potential for sexual conflict. In contrast, in reduced broods visit rates and alternation may become lower due to the smaller investment that is needed for reduced broods. We show that the level of alternation did not differ in response to the manipulated brood sizes, despite a directional change in visit rates for enlarged and reduced broods as expected. Nestlings did not benefit from high levels of alternation as no effects on nestling mass gain were present in either of the different manipulations. These findings indicate that alternation does not serve as a mechanism to motivate each other to feed at higher rates. Parents hence appeared to be inflexible in their level of alternation. We therefore suggest that the level of alternation might reflect a fixed agreement about the relative investment by each of the caring parents.https://peerj.com/articles/6826.pdfConditional cooperationAlternationParental investmentSexual conflictBlue titsBrood size manipulation
spellingShingle Maaike Griffioen
Wendt Müller
Arne Iserbyt
A fixed agreement—consequences of brood size manipulation on alternation in blue tits
PeerJ
Conditional cooperation
Alternation
Parental investment
Sexual conflict
Blue tits
Brood size manipulation
title A fixed agreement—consequences of brood size manipulation on alternation in blue tits
title_full A fixed agreement—consequences of brood size manipulation on alternation in blue tits
title_fullStr A fixed agreement—consequences of brood size manipulation on alternation in blue tits
title_full_unstemmed A fixed agreement—consequences of brood size manipulation on alternation in blue tits
title_short A fixed agreement—consequences of brood size manipulation on alternation in blue tits
title_sort fixed agreement consequences of brood size manipulation on alternation in blue tits
topic Conditional cooperation
Alternation
Parental investment
Sexual conflict
Blue tits
Brood size manipulation
url https://peerj.com/articles/6826.pdf
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