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Divorce, dispersal and incest avoidance in the cooperatively breeding superb fairy-wren Malurus cyaneus

Date

2003

Authors

Cockburn, Andrew
Osmond, Helen
Mulder, Raoul A
Green, David
Double, Michael

Journal Title

Journal ISSN

Volume Title

Publisher

British Ecological Society

Abstract

1. Between 1988 and 2001, we studied social relationships in the superb fairy-wren Malurus cyaneus (Latham), a cooperative breeder with male helpers in which extra-group fertilizations are more common than within-pair fertilizations. 2. Unlike other fairy-wren species, females never bred on their natal territory. First-year females dispersed either directly from their natal territory to a breeding vacancy or to a foreign 'staging-post' territory where they spent their first winter as a subordinate. Females dispersing to a foreign territory settled in larger groups. Females on foreign territories inherited the territory if the dominant female died, and were sometimes able to split the territory into two by pairing with a helper male. However, most dispersed again to obtain a vacancy. 3. Females dispersing from a staging post usually gained a neighbouring vacancy, but females gaining a vacancy directly from their natal territory travelled further, perhaps to avoid pairing or mating with related males. 4. Females frequently divorced their partner, although the majority of relationships were terminated by the death of one of the pair. If death did not intervene, one-third of pairings were terminated by female-initiated divorce within 1000 days. 5. Three divorce syndromes were recognized. First, females that failed to obtain a preferred territory moved to territories with more helpers. Secondly, females that became paired to their sons when their partner died usually divorced away from them. Thirdly, females that have been in a long relationship divorce once a son has gained the senior helper position. 6. Dispersal to avoid pairing with sons is consistent with incest avoidance. However, there may be two additional benefits. Mothers do not mate with their sons, so dispersal by the mother liberates her sons to compete for within-group matings. Further, divorcing once their son has become a breeder or a senior helper allows the female to start sons in a queue for dominance on another territory. Females that do not take this option face constraints on their ability to recruit more sons into the local neighbourhood.

Description

Keywords

Keywords: cooperative breeding; inbreeding avoidance; natal dispersal; reproductive behavior; Malurus; Malurus cyaneus; Troglodytes troglodytes Breeding dispersal; Cooperative breeding; Divorce; Incest avoidance; Malurus; Natal dispersal

Citation

Source

Journal of Animal Ecology

Type

Journal article

Book Title

Entity type

Access Statement

License Rights

DOI

10.1046/j.1365-2656.2003.00694.x

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