Evolution of parental roles in provisioning birds: diet determines role asymmetry in raptors

Geir A. Sonerud, Ronny Steen, Vidar Selås, Ole M. Aanonsen, Gunn-Henny Aasen, Kristine L. Fagerland, Annette Fosså, Lena Kristiansen, Line M. Løw, Mads E. Rønning, Sarah K. Skouen, Espen Asakskogen, Hilde M. Johansen, Jon T. Johnsen, Lise I. Karlsen, Gunnar C. Nyhus, Line T. Røed, Kristin Skar, Bjørn-Arild Sveen, Reidar Tveiten and Tore Slagsvold

Behavioral Ecology, 2014, vol. 25, issue 4, 762-772

Abstract: Raptors are known for asymmetric parental roles, with the female brooding and feeding offspring, and the male providing food, usually assisted by the female from the latter part of the rearing period. Yet, the evolution of this role asymmetry is poorly understood. From filming prey delivery and handling in 61 nests of 9 raptor species, we show that the female role is related to prey size and prey type. Within species, nestlings were less likely to ingest larger prey unassisted, independent of increasing ability of unassisted feeding with increasing age. Feeding time increased with prey size and was longer for avian than for mammalian prey of the same size when nestlings fed unassisted. Across species, the female partitioned prey and fed offspring for a longer portion of the rearing period as prey size increased and as the diet contained more birds. Providing for the family selects for small body size; hence, extended female confinement as sedentary food processor for offspring would leave greater potential for differential selection on male and female body size. This may explain the female-biased size dimorphism among raptors, which becomes larger as diet changes from insects via reptiles and mammals to birds and as relative prey size increases. Symmetric parental roles and no female-biased size dimorphism would be expected in birds providing insects or other food that nestlings swallow without maternal assistance. Prey type and prey size would be important also for sexual conflicts and evolution of polygamy and mate desertion in birds providing for offspring.

Date: 2014
References: View references in EconPapers View complete reference list from CitEc
Citations:

Downloads: (external link)
http://hdl.handle.net/10.1093/beheco/aru053 (application/pdf)
Access to full text is restricted to subscribers.

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:oup:beheco:v:25:y:2014:i:4:p:762-772.

Ordering information: This journal article can be ordered from
https://academic.oup.com/journals

Access Statistics for this article

Behavioral Ecology is currently edited by Louise Barrett

More articles in Behavioral Ecology from International Society for Behavioral Ecology Oxford University Press, Great Clarendon Street, Oxford OX2 6DP, UK.
Bibliographic data for series maintained by Oxford University Press ().