In cooperatively breeding vertebrates, indirect fitness benefits are maximized by subordinates who choose to help their own closely related kin after accurately assessing their relatedness to the group's offspring. Here we show that in the cooperatively breeding Seychelles warbler (Acrocephalus sechellensis), female subordinates help to raise new nestlings by providing them with food only when the offspring are being raised by parents who also fed the subordinates themselves when they were young. These helper females use the continued presence of the primary female, rather than of the primary male, as their provisioning cue — presumably because female infidelity is rife in this species, making their relatedness to the father less reliable.

CD Oliver

CK Kelly

FH Bormann

Jeremy S. Wilson

MB Bush

Patrick J. Baker

PW Richards

R Condit

Richardson, David

Komdeur, J

Burke, T

Lund University Publications

Altruism and infidelity among warblers

In cooperatively breeding vertebrates, indirect fitness benefits1,2 are maximized by subordinates who choose to help their own closely related kin after accurately assessing their relatedness to the group's offspring3,4,5. Here we show that in the cooperatively breeding Seychelles warbler (Acrocephalus sechellensis), female subordinates help to raise new nestlings by providing them with food only when the offspring are being raised by parents who also fed the subordinates themselves when they were young3. These helper females use the continued presence of the primary female, rather than of the primary male, as their provisioning cue — presumably because female infidelity is rife in this species6, making their relatedness to the father less reliable

Richardson, David S.

Komdeur, Jan

Burke, Terry

NARCIS 

Crossref

University of Groningen

   University of GroningenAltruism and infidelity among warblersRichardson, DS; Komdeur, J; Burke, T; Richardson, David S.Published in:NatureDOI:10.1038/422580aIMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite fromit. Please check the document version below.Document VersionPublisher's PDF, also known as Version of recordPublication date:2003Link to publication in University of Groningen/UMCG research databaseCitation for published version (APA):Richardson, DS., Komdeur, J., Burke, T., & Richardson, D. S. (2003). Altruism and infidelity amongwarblers. Nature, 422(6932), 580-580. https://doi.org/10.1038/422580aCopyrightOther than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of theauthor(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).Take-down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediatelyand investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons thenumber of authors shown on this cover page is limited to 10 maximum.Download date: 12-11-2019© 2003 Nature PublishingGroupfemale. However, the continued presence ofthe primary female explained provisioningmore reliably (F1,11413.72, P40.003,R240.55) than genetic estimates of sub-ordinate–nestling or subordinate–primaryfemale relatedness (F1,1142.14, P40.17;F1,1140.06, P40.81, respectively). Theseresults confirm that the presence of the pri-mary female who raised the subordinate islikely to be used as a cue to determine whento provision. Previous findings that helperscan distinguish between siblings and half-siblings3 may have been an artefact causedby helpers assisting only their mothers.Our results show that female subordi-nates can use an indirect but reliable cue to assess their relatedness to nestlings, andthat this assessment of kinship determinesprovisioning rates. In A. sechellensis, theamount of food brought to the nestlingdetermines fledging success and first-yearsurvival, and the presence of a helperincreases the number of young who arefledged on a territory10. The preferentialprovisioning of related nestlings by femalesubordinates will therefore increase thenumber of related offspring produced. Inour study, the number of fledglings pro-duced on a territory increased significantly(by 17%) for each subordinate present(after exclusion of direct parentage)8.Both direct8 and indirect benefits maybe important within this cooperativebreeding system as, by using effective dis-crimination, subordinates are able to maxi-mize the indirect benefit gained within asystem that is driven primarily by directbenefits8. Our findings show that, in thepresence of a high frequency of female infi-delity, an associative learning mechanismhas evolved to focus on the mother at thenest — the only sex to which the subordi-nates are reliably related.David S. Richardson*†, Jan Komdeur‡,Terry Burke**Department of Animal and Plant Sciences,University of Sheffield, Sheffield S10 2TN, UK†Department of Animal Ecology, University ofLund, 223 62 Lund, Swedene-mail: david.richardson@zooekol.lu.se‡Zoological Laboratory, University of Groningen,PO Box 14, 9750 AA Haren, The Netherlands, andDepartment of Zoology, University of Melbourne,Victoria 3010, Australia 1. Hamilton, W. D. J. Theor. Biol. 7, 1–52 (1964).2. Emlen, S. T. Proc. Natl Acad. Sci. USA 92, 8092–8099 (1995).3. Komdeur, J. Proc. R. Soc. Lond. B 256, 47–52 (1994).4. Russell, A. F. & Hatchwell, B. J. Proc. R. Soc. Lond. B 268,2169–2174 (2001).5. Hatchwell, B. J., Ross, D. J., Fowlie, M. K. & McGowan, A. Proc. R. Soc. Lond. B 268, 885–890 (2001).6. Richardson, D., Jury, F., Blaakmeer, K., Komdeur, J. & Burke, T.Mol. Ecol. 10, 2263–2273 (2001).7. Komdeur, J. Proc. R. Soc. Lond. B 263, 661–666 (1996).8. Richardson, D. S., Burke, T. & Komdeur, J. Evolution 56,2313–2321 (2002).9. Goodnight, K. F. & Queller, D. C. Mol. Ecol. 8,1231–1234 (1999).10.Komdeur, J. Behav. Ecol. Sociobiol. 34, 175–186 (1994).Competing financial interests: declared none.COMMUNICATIONS ARISINGPlant ecologyTree-species competitionand coexistenceHow apparently similar plant speciescoexist is a puzzle. Kelly and Bowler1claim that environmental fluctuationpromotes the coexistence of tree species byalternately favouring recruitment of com-mon and rare congeners in a dry tropicalforest. Here I argue that current knowledgeof tropical-forest ecology does not supportthe authors’ focus on congeneric competi-tion, and show that their use of diameterdistributions to date recruitment fluctua-tions may be misleading. It is thereforedoubtful, at this stage, that recruitmentpatterns of the authors’ congeneric pairscan be linked to the sort of competitiondynamic that they envisage. Kelly and Bowler’s two-component lottery model assumes that seedlings of580 NATURE | VOL 422 | 10 APRIL 2003 | www.nature.com/natureAvian behaviourAltruism and infidelityamong warblersIn cooperatively breeding vertebrates, indirect fitness benefits1,2 are maximizedby subordinates who choose to help theirown closely related kin after accuratelyassessing their relatedness to the group’s offspring3–5. Here we show that in the cooperatively breeding Seychelles warbler(Acrocephalus sechellensis), female subordi-nates help to raise new nestlings by provid-ing them with food only when the offspringare being raised by parents who also fed the subordinates themselves when they wereyoung3. These helper females use the contin-ued presence of the primary female, ratherthan of the primary male, as their provision-ing cue — presumably because female infidelity is rife in this species6, making theirrelatedness to the father less reliable. In A. sechellensis, female offspring nor-mally become subordinate within theirnatal group7,8 and often help to raise depen-dent young7. We studied the provisioningbehaviour (feeds given per hour) of 21colour-ringed female subordinates. Repro-ductive sharing and high levels of extra-pairpaternity occur in this species6; we thereforeassessed parentage and genetic relatednessby using microsatellite DNA markers8. Sub-ordinate parents (that is, subordinates whohad also produced a nestling in the helpednest) always provisioned and were excludedfrom subsequent analysis (n48).In a general linear model analysis, theprovisioning behaviour of non-parent subordinates was influenced positively bysubordinate–nestling relatedness (F1,1144.82,P40.05, R240.31), whereas subordinateage, sex, number of nestlings, number ofsubordinates (or feeding adults) and terri-tory quality had no significant effect. Acomparison of relatedness9 to the nestlingsof subordinates who helped with those thatdid not (Fig. 1a) indicates that helpers weresignificantly related to nestling(s), whereasnon-helpers were not (mean relatedness,0.27 versus 10.05, respectively). The continued presence of the primaryfemale, but not of the primary male, was a reliable cue of subordinate–nestling relatedness; subordinate–primary femalerelatedness predicted subordinate–nestlingrelatedness (F1,38427.37, P*0.001), butsubordinate–primary male relatedness didnot (F2,3742.11, P40.16). Subordinatesprovisioned significantly more often whentheir putative mother was still present, but provisioning was unaffected by thepresence or absence of the putative father(Fig. 1b). Subordinates may determine when toprovision by directly assessing their related-ness to either the nestling(s) or the primarybrief communications–0.40–0.200.000.200.40Helpers Non-helpersMean subordinate–nestling relatedness **0246810Primary male Primary femaleFeeds per hourNS**abFigure 1 Provisioning by subordinate female, non-parent Seychelleswarblers (Acrocephalus sechellensis). a, Provisioning in relation tothe pairwise relatedness between subordinates and nestlings (subordinate helper–nestling relatedness versus non-related:0.2750.16 versus 0, one-sample t-test, t 744.64, P*0.002;helpers versus non-helpers: 0.2750.16, n48 versus10.0550.20, n45; t1143.13, P40.01). b, Provisioning in relation to the presence (purple bars) or absence (green bars) of thesubordinate’s putative parents (presence versus absence of putativemother: 7.5752.44, n46 versus 1.4353.60, n47; t-test,t1143.71, P40.003; presence versus absence of putative father:4.3054.89, n44 versus 4.2454.29, n48; t1140.02, P40.98).Error bars, means5s.e.; asterisks indicate statistical significance.

University of East Anglia digital repository

Coexistence of tropical tree species

   University of GroningenAltruism and infidelity among warblersRichardson, David S.; Komdeur, Jan; Burke, TerryPublished in:NatureDOI:10.1038/422580aIMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite fromit. Please check the document version below.Document VersionPublisher's PDF, also known as Version of recordPublication date:2003Link to publication in University of Groningen/UMCG research databaseCitation for published version (APA):Richardson, D. S., Komdeur, J., & Burke, T. (2003). Altruism and infidelity among warblers. Nature,422(6932), 580-580. https://doi.org/10.1038/422580aCopyrightOther than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of theauthor(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).The publication may also be distributed here under the terms of Article 25fa of the Dutch Copyright Act, indicated by the “Taverne” license.More information can be found on the University of Groningen website: https://www.rug.nl/library/open-access/self-archiving-pure/taverne-amendment.Take-down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediatelyand investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons thenumber of authors shown on this cover page is limited to 10 maximum.Download date: 26-04-2023© 2003 Nature PublishingGroupfemale. However, the continued presence ofthe primary female explained provisioningmore reliably (F1,11413.72, P40.003,R240.55) than genetic estimates of sub-ordinate–nestling or subordinate–primaryfemale relatedness (F1,1142.14, P40.17;F1,1140.06, P40.81, respectively). Theseresults confirm that the presence of the pri-mary female who raised the subordinate islikely to be used as a cue to determine whento provision. Previous findings that helperscan distinguish between siblings and half-siblings3 may have been an artefact causedby helpers assisting only their mothers.Our results show that female subordi-nates can use an indirect but reliable cue to assess their relatedness to nestlings, andthat this assessment of kinship determinesprovisioning rates. In A. sechellensis, theamount of food brought to the nestlingdetermines fledging success and first-yearsurvival, and the presence of a helperincreases the number of young who arefledged on a territory10. The preferentialprovisioning of related nestlings by femalesubordinates will therefore increase thenumber of related offspring produced. Inour study, the number of fledglings pro-duced on a territory increased significantly(by 17%) for each subordinate present(after exclusion of direct parentage)8.Both direct8 and indirect benefits maybe important within this cooperativebreeding system as, by using effective dis-crimination, subordinates are able to maxi-mize the indirect benefit gained within asystem that is driven primarily by directbenefits8. Our findings show that, in thepresence of a high frequency of female infi-delity, an associative learning mechanismhas evolved to focus on the mother at thenest — the only sex to which the subordi-nates are reliably related.David S. Richardson*†, Jan Komdeur‡,Terry Burke**Department of Animal and Plant Sciences,University of Sheffield, Sheffield S10 2TN, UK†Department of Animal Ecology, University ofLund, 223 62 Lund, Swedene-mail: david.richardson@zooekol.lu.se‡Zoological Laboratory, University of Groningen,PO Box 14, 9750 AA Haren, The Netherlands, andDepartment of Zoology, University of Melbourne,Victoria 3010, Australia 1. Hamilton, W. D. J. Theor. Biol. 7, 1–52 (1964).2. Emlen, S. T. Proc. Natl Acad. Sci. USA 92, 8092–8099 (1995).3. Komdeur, J. Proc. R. Soc. Lond. B 256, 47–52 (1994).4. Russell, A. F. & Hatchwell, B. J. Proc. R. Soc. Lond. B 268,2169–2174 (2001).5. Hatchwell, B. J., Ross, D. J., Fowlie, M. K. & McGowan, A. Proc. R. Soc. Lond. B 268, 885–890 (2001).6. Richardson, D., Jury, F., Blaakmeer, K., Komdeur, J. & Burke, T.Mol. Ecol. 10, 2263–2273 (2001).7. Komdeur, J. Proc. R. Soc. Lond. B 263, 661–666 (1996).8. Richardson, D. S., Burke, T. & Komdeur, J. Evolution 56,2313–2321 (2002).9. Goodnight, K. F. & Queller, D. C. Mol. Ecol. 8,1231–1234 (1999).10.Komdeur, J. Behav. Ecol. Sociobiol. 34, 175–186 (1994).Competing financial interests: declared none.COMMUNICATIONS ARISINGPlant ecologyTree-species competitionand coexistenceHow apparently similar plant speciescoexist is a puzzle. Kelly and Bowler1claim that environmental fluctuationpromotes the coexistence of tree species byalternately favouring recruitment of com-mon and rare congeners in a dry tropicalforest. Here I argue that current knowledgeof tropical-forest ecology does not supportthe authors’ focus on congeneric competi-tion, and show that their use of diameterdistributions to date recruitment fluctua-tions may be misleading. It is thereforedoubtful, at this stage, that recruitmentpatterns of the authors’ congeneric pairscan be linked to the sort of competitiondynamic that they envisage. Kelly and Bowler’s two-component lottery model assumes that seedlings of580 NATURE | VOL 422 | 10 APRIL 2003 | www.nature.com/natureAvian behaviourAltruism and infidelityamong warblersIn cooperatively breeding vertebrates, indirect fitness benefits1,2 are maximizedby subordinates who choose to help theirown closely related kin after accuratelyassessing their relatedness to the group’s offspring3–5. Here we show that in the cooperatively breeding Seychelles warbler(Acrocephalus sechellensis), female subordi-nates help to raise new nestlings by provid-ing them with food only when the offspringare being raised by parents who also fed the subordinates themselves when they wereyoung3. These helper females use the contin-ued presence of the primary female, ratherthan of the primary male, as their provision-ing cue — presumably because female infidelity is rife in this species6, making theirrelatedness to the father less reliable. In A. sechellensis, female offspring nor-mally become subordinate within theirnatal group7,8 and often help to raise depen-dent young7. We studied the provisioningbehaviour (feeds given per hour) of 21colour-ringed female subordinates. Repro-ductive sharing and high levels of extra-pairpaternity occur in this species6; we thereforeassessed parentage and genetic relatednessby using microsatellite DNA markers8. Sub-ordinate parents (that is, subordinates whohad also produced a nestling in the helpednest) always provisioned and were excludedfrom subsequent analysis (n48).In a general linear model analysis, theprovisioning behaviour of non-parent subordinates was influenced positively bysubordinate–nestling relatedness (F1,1144.82,P40.05, R240.31), whereas subordinateage, sex, number of nestlings, number ofsubordinates (or feeding adults) and terri-tory quality had no significant effect. Acomparison of relatedness9 to the nestlingsof subordinates who helped with those thatdid not (Fig. 1a) indicates that helpers weresignificantly related to nestling(s), whereasnon-helpers were not (mean relatedness,0.27 versus 10.05, respectively). The continued presence of the primaryfemale, but not of the primary male, was a reliable cue of subordinate–nestling relatedness; subordinate–primary femalerelatedness predicted subordinate–nestlingrelatedness (F1,38427.37, P*0.001), butsubordinate–primary male relatedness didnot (F2,3742.11, P40.16). Subordinatesprovisioned significantly more often whentheir putative mother was still present, but provisioning was unaffected by thepresence or absence of the putative father(Fig. 1b). Subordinates may determine when toprovision by directly assessing their related-ness to either the nestling(s) or the primarybrief communications–0.40–0.200.000.200.40Helpers Non-helpersMean subordinate–nestling relatedness **0246810Primary male Primary femaleFeeds per hourNS**abFigure 1 Provisioning by subordinate female, non-parent Seychelleswarblers (Acrocephalus sechellensis). a, Provisioning in relation tothe pairwise relatedness between subordinates and nestlings (subordinate helper–nestling relatedness versus non-related:0.2750.16 versus 0, one-sample t-test, t 744.64, P*0.002;helpers versus non-helpers: 0.2750.16, n48 versus10.0550.20, n45; t1143.13, P40.01). b, Provisioning in relation to the presence (purple bars) or absence (green bars) of thesubordinate’s putative parents (presence versus absence of putativemother: 7.5752.44, n46 versus 1.4353.60, n47; t-test,t1143.71, P40.003; presence versus absence of putative father:4.3054.89, n44 versus 4.2454.29, n48; t1140.02, P40.98).Error bars, means5s.e.; asterisks indicate statistical significance.

English

Richardson, David S.,

Komdeur, Jan,

Burke, Terry,

University of Groningen Digital Archive

ARTS repository - University of Groningen

   University of GroningenAltruism and infidelity among warblersRichardson, David S.; Komdeur, Jan; Burke, TerryPublished in:NatureDOI:10.1038/422580aIMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite fromit. Please check the document version below.Document VersionPublisher's PDF, also known as Version of recordPublication date:2003Link to publication in University of Groningen/UMCG research databaseCitation for published version (APA):Richardson, D. S., Komdeur, J., & Burke, T. (2003). Altruism and infidelity among warblers. Nature,422(6932), 580-580. https://doi.org/10.1038/422580aCopyrightOther than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of theauthor(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).The publication may also be distributed here under the terms of Article 25fa of the Dutch Copyright Act, indicated by the “Taverne” license.More information can be found on the University of Groningen website: https://www.rug.nl/library/open-access/self-archiving-pure/taverne-amendment.Take-down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediatelyand investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons thenumber of authors shown on this cover page is limited to 10 maximum.Download date: 17-07-2023© 2003 Nature PublishingGroupfemale. However, the continued presence ofthe primary female explained provisioningmore reliably (F1,11413.72, P40.003,R240.55) than genetic estimates of sub-ordinate–nestling or subordinate–primaryfemale relatedness (F1,1142.14, P40.17;F1,1140.06, P40.81, respectively). Theseresults confirm that the presence of the pri-mary female who raised the subordinate islikely to be used as a cue to determine whento provision. Previous findings that helperscan distinguish between siblings and half-siblings3 may have been an artefact causedby helpers assisting only their mothers.Our results show that female subordi-nates can use an indirect but reliable cue to assess their relatedness to nestlings, andthat this assessment of kinship determinesprovisioning rates. In A. sechellensis, theamount of food brought to the nestlingdetermines fledging success and first-yearsurvival, and the presence of a helperincreases the number of young who arefledged on a territory10. The preferentialprovisioning of related nestlings by femalesubordinates will therefore increase thenumber of related offspring produced. Inour study, the number of fledglings pro-duced on a territory increased significantly(by 17%) for each subordinate present(after exclusion of direct parentage)8.Both direct8 and indirect benefits maybe important within this cooperativebreeding system as, by using effective dis-crimination, subordinates are able to maxi-mize the indirect benefit gained within asystem that is driven primarily by directbenefits8. Our findings show that, in thepresence of a high frequency of female infi-delity, an associative learning mechanismhas evolved to focus on the mother at thenest — the only sex to which the subordi-nates are reliably related.David S. Richardson*†, Jan Komdeur‡,Terry Burke**Department of Animal and Plant Sciences,University of Sheffield, Sheffield S10 2TN, UK†Department of Animal Ecology, University ofLund, 223 62 Lund, Swedene-mail: david.richardson@zooekol.lu.se‡Zoological Laboratory, University of Groningen,PO Box 14, 9750 AA Haren, The Netherlands, andDepartment of Zoology, University of Melbourne,Victoria 3010, Australia 1. Hamilton, W. D. J. Theor. Biol. 7, 1–52 (1964).2. Emlen, S. T. Proc. Natl Acad. Sci. USA 92, 8092–8099 (1995).3. Komdeur, J. Proc. R. Soc. Lond. B 256, 47–52 (1994).4. Russell, A. F. & Hatchwell, B. J. Proc. R. Soc. Lond. B 268,2169–2174 (2001).5. Hatchwell, B. J., Ross, D. J., Fowlie, M. K. & McGowan, A. Proc. R. Soc. Lond. B 268, 885–890 (2001).6. Richardson, D., Jury, F., Blaakmeer, K., Komdeur, J. & Burke, T.Mol. Ecol. 10, 2263–2273 (2001).7. Komdeur, J. Proc. R. Soc. Lond. B 263, 661–666 (1996).8. Richardson, D. S., Burke, T. & Komdeur, J. Evolution 56,2313–2321 (2002).9. Goodnight, K. F. & Queller, D. C. Mol. Ecol. 8,1231–1234 (1999).10.Komdeur, J. Behav. Ecol. Sociobiol. 34, 175–186 (1994).Competing financial interests: declared none.COMMUNICATIONS ARISINGPlant ecologyTree-species competitionand coexistenceHow apparently similar plant speciescoexist is a puzzle. Kelly and Bowler1claim that environmental fluctuationpromotes the coexistence of tree species byalternately favouring recruitment of com-mon and rare congeners in a dry tropicalforest. Here I argue that current knowledgeof tropical-forest ecology does not supportthe authors’ focus on congeneric competi-tion, and show that their use of diameterdistributions to date recruitment fluctua-tions may be misleading. It is thereforedoubtful, at this stage, that recruitmentpatterns of the authors’ congeneric pairscan be linked to the sort of competitiondynamic that they envisage. Kelly and Bowler’s two-component lottery model assumes that seedlings of580 NATURE | VOL 422 | 10 APRIL 2003 | www.nature.com/natureAvian behaviourAltruism and infidelityamong warblersIn cooperatively breeding vertebrates, indirect fitness benefits1,2 are maximizedby subordinates who choose to help theirown closely related kin after accuratelyassessing their relatedness to the group’s offspring3–5. Here we show that in the cooperatively breeding Seychelles warbler(Acrocephalus sechellensis), female subordi-nates help to raise new nestlings by provid-ing them with food only when the offspringare being raised by parents who also fed the subordinates themselves when they wereyoung3. These helper females use the contin-ued presence of the primary female, ratherthan of the primary male, as their provision-ing cue — presumably because female infidelity is rife in this species6, making theirrelatedness to the father less reliable. In A. sechellensis, female offspring nor-mally become subordinate within theirnatal group7,8 and often help to raise depen-dent young7. We studied the provisioningbehaviour (feeds given per hour) of 21colour-ringed female subordinates. Repro-ductive sharing and high levels of extra-pairpaternity occur in this species6; we thereforeassessed parentage and genetic relatednessby using microsatellite DNA markers8. Sub-ordinate parents (that is, subordinates whohad also produced a nestling in the helpednest) always provisioned and were excludedfrom subsequent analysis (n48).In a general linear model analysis, theprovisioning behaviour of non-parent subordinates was influenced positively bysubordinate–nestling relatedness (F1,1144.82,P40.05, R240.31), whereas subordinateage, sex, number of nestlings, number ofsubordinates (or feeding adults) and terri-tory quality had no significant effect. Acomparison of relatedness9 to the nestlingsof subordinates who helped with those thatdid not (Fig. 1a) indicates that helpers weresignificantly related to nestling(s), whereasnon-helpers were not (mean relatedness,0.27 versus 10.05, respectively). The continued presence of the primaryfemale, but not of the primary male, was a reliable cue of subordinate–nestling relatedness; subordinate–primary femalerelatedness predicted subordinate–nestlingrelatedness (F1,38427.37, P*0.001), butsubordinate–primary male relatedness didnot (F2,3742.11, P40.16). Subordinatesprovisioned significantly more often whentheir putative mother was still present, but provisioning was unaffected by thepresence or absence of the putative father(Fig. 1b). Subordinates may determine when toprovision by directly assessing their related-ness to either the nestling(s) or the primarybrief communications–0.40–0.200.000.200.40Helpers Non-helpersMean subordinate–nestling relatedness **0246810Primary male Primary femaleFeeds per hourNS**abFigure 1 Provisioning by subordinate female, non-parent Seychelleswarblers (Acrocephalus sechellensis). a, Provisioning in relation tothe pairwise relatedness between subordinates and nestlings (subordinate helper–nestling relatedness versus non-related:0.2750.16 versus 0, one-sample t-test, t 744.64, P*0.002;helpers versus non-helpers: 0.2750.16, n48 versus10.0550.20, n45; t1143.13, P40.01). b, Provisioning in relation to the presence (purple bars) or absence (green bars) of thesubordinate’s putative parents (presence versus absence of putativemother: 7.5752.44, n46 versus 1.4353.60, n47; t-test,t1143.71, P40.003; presence versus absence of putative father:4.3054.89, n44 versus 4.2454.29, n48; t1140.02, P40.98).Error bars, means5s.e.; asterisks indicate statistical significance.

   University of GroningenAltruism and infidelity among warblersRichardson, David S.; Komdeur, Jan; Burke, TerryPublished in:NatureDOI:10.1038/422580aIMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite fromit. Please check the document version below.Document VersionPublisher's PDF, also known as Version of recordPublication date:2003Link to publication in University of Groningen/UMCG research databaseCitation for published version (APA):Richardson, D. S., Komdeur, J., & Burke, T. (2003). Altruism and infidelity among warblers. Nature,422(6932), 580-580. https://doi.org/10.1038/422580aCopyrightOther than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of theauthor(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).The publication may also be distributed here under the terms of Article 25fa of the Dutch Copyright Act, indicated by the “Taverne” license.More information can be found on the University of Groningen website: https://www.rug.nl/library/open-access/self-archiving-pure/taverne-amendment.Take-down policyIf you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediatelyand investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons thenumber of authors shown on this cover page is limited to 10 maximum.Download date: 13-02-2023© 2003 Nature PublishingGroupfemale. However, the continued presence ofthe primary female explained provisioningmore reliably (F1,11413.72, P40.003,R240.55) than genetic estimates of sub-ordinate–nestling or subordinate–primaryfemale relatedness (F1,1142.14, P40.17;F1,1140.06, P40.81, respectively). Theseresults confirm that the presence of the pri-mary female who raised the subordinate islikely to be used as a cue to determine whento provision. Previous findings that helperscan distinguish between siblings and half-siblings3 may have been an artefact causedby helpers assisting only their mothers.Our results show that female subordi-nates can use an indirect but reliable cue to assess their relatedness to nestlings, andthat this assessment of kinship determinesprovisioning rates. In A. sechellensis, theamount of food brought to the nestlingdetermines fledging success and first-yearsurvival, and the presence of a helperincreases the number of young who arefledged on a territory10. The preferentialprovisioning of related nestlings by femalesubordinates will therefore increase thenumber of related offspring produced. Inour study, the number of fledglings pro-duced on a territory increased significantly(by 17%) for each subordinate present(after exclusion of direct parentage)8.Both direct8 and indirect benefits maybe important within this cooperativebreeding system as, by using effective dis-crimination, subordinates are able to maxi-mize the indirect benefit gained within asystem that is driven primarily by directbenefits8. Our findings show that, in thepresence of a high frequency of female infi-delity, an associative learning mechanismhas evolved to focus on the mother at thenest — the only sex to which the subordi-nates are reliably related.David S. Richardson*†, Jan Komdeur‡,Terry Burke**Department of Animal and Plant Sciences,University of Sheffield, Sheffield S10 2TN, UK†Department of Animal Ecology, University ofLund, 223 62 Lund, Swedene-mail: david.richardson@zooekol.lu.se‡Zoological Laboratory, University of Groningen,PO Box 14, 9750 AA Haren, The Netherlands, andDepartment of Zoology, University of Melbourne,Victoria 3010, Australia 1. Hamilton, W. D. J. Theor. Biol. 7, 1–52 (1964).2. Emlen, S. T. Proc. Natl Acad. Sci. USA 92, 8092–8099 (1995).3. Komdeur, J. Proc. R. Soc. Lond. B 256, 47–52 (1994).4. Russell, A. F. & Hatchwell, B. J. Proc. R. Soc. Lond. B 268,2169–2174 (2001).5. Hatchwell, B. J., Ross, D. J., Fowlie, M. K. & McGowan, A. Proc. R. Soc. Lond. B 268, 885–890 (2001).6. Richardson, D., Jury, F., Blaakmeer, K., Komdeur, J. & Burke, T.Mol. Ecol. 10, 2263–2273 (2001).7. Komdeur, J. Proc. R. Soc. Lond. B 263, 661–666 (1996).8. Richardson, D. S., Burke, T. & Komdeur, J. Evolution 56,2313–2321 (2002).9. Goodnight, K. F. & Queller, D. C. Mol. Ecol. 8,1231–1234 (1999).10.Komdeur, J. Behav. Ecol. Sociobiol. 34, 175–186 (1994).Competing financial interests: declared none.COMMUNICATIONS ARISINGPlant ecologyTree-species competitionand coexistenceHow apparently similar plant speciescoexist is a puzzle. Kelly and Bowler1claim that environmental fluctuationpromotes the coexistence of tree species byalternately favouring recruitment of com-mon and rare congeners in a dry tropicalforest. Here I argue that current knowledgeof tropical-forest ecology does not supportthe authors’ focus on congeneric competi-tion, and show that their use of diameterdistributions to date recruitment fluctua-tions may be misleading. It is thereforedoubtful, at this stage, that recruitmentpatterns of the authors’ congeneric pairscan be linked to the sort of competitiondynamic that they envisage. Kelly and Bowler’s two-component lottery model assumes that seedlings of580 NATURE | VOL 422 | 10 APRIL 2003 | www.nature.com/natureAvian behaviourAltruism and infidelityamong warblersIn cooperatively breeding vertebrates, indirect fitness benefits1,2 are maximizedby subordinates who choose to help theirown closely related kin after accuratelyassessing their relatedness to the group’s offspring3–5. Here we show that in the cooperatively breeding Seychelles warbler(Acrocephalus sechellensis), female subordi-nates help to raise new nestlings by provid-ing them with food only when the offspringare being raised by parents who also fed the subordinates themselves when they wereyoung3. These helper females use the contin-ued presence of the primary female, ratherthan of the primary male, as their provision-ing cue — presumably because female infidelity is rife in this species6, making theirrelatedness to the father less reliable. In A. sechellensis, female offspring nor-mally become subordinate within theirnatal group7,8 and often help to raise depen-dent young7. We studied the provisioningbehaviour (feeds given per hour) of 21colour-ringed female subordinates. Repro-ductive sharing and high levels of extra-pairpaternity occur in this species6; we thereforeassessed parentage and genetic relatednessby using microsatellite DNA markers8. Sub-ordinate parents (that is, subordinates whohad also produced a nestling in the helpednest) always provisioned and were excludedfrom subsequent analysis (n48).In a general linear model analysis, theprovisioning behaviour of non-parent subordinates was influenced positively bysubordinate–nestling relatedness (F1,1144.82,P40.05, R240.31), whereas subordinateage, sex, number of nestlings, number ofsubordinates (or feeding adults) and terri-tory quality had no significant effect. Acomparison of relatedness9 to the nestlingsof subordinates who helped with those thatdid not (Fig. 1a) indicates that helpers weresignificantly related to nestling(s), whereasnon-helpers were not (mean relatedness,0.27 versus 10.05, respectively). The continued presence of the primaryfemale, but not of the primary male, was a reliable cue of subordinate–nestling relatedness; subordinate–primary femalerelatedness predicted subordinate–nestlingrelatedness (F1,38427.37, P*0.001), butsubordinate–primary male relatedness didnot (F2,3742.11, P40.16). Subordinatesprovisioned significantly more often whentheir putative mother was still present, but provisioning was unaffected by thepresence or absence of the putative father(Fig. 1b). Subordinates may determine when toprovision by directly assessing their related-ness to either the nestling(s) or the primarybrief communications–0.40–0.200.000.200.40Helpers Non-helpersMean subordinate–nestling relatedness **0246810Primary male Primary femaleFeeds per hourNS**abFigure 1 Provisioning by subordinate female, non-parent Seychelleswarblers (Acrocephalus sechellensis). a, Provisioning in relation tothe pairwise relatedness between subordinates and nestlings (subordinate helper–nestling relatedness versus non-related:0.2750.16 versus 0, one-sample t-test, t 744.64, P*0.002;helpers versus non-helpers: 0.2750.16, n48 versus10.0550.20, n45; t1143.13, P40.01). b, Provisioning in relation to the presence (purple bars) or absence (green bars) of thesubordinate’s putative parents (presence versus absence of putativemother: 7.5752.44, n46 versus 1.4353.60, n47; t-test,t1143.71, P40.003; presence versus absence of putative father:4.3054.89, n44 versus 4.2454.29, n48; t1140.02, P40.98).Error bars, means5s.e.; asterisks indicate statistical significance.

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Altruism and infidelity among warblers.

Altruism and infidelity among warblers.

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