Parentage assignment and extra‐group paternity in a cooperative breeder: the Seychelles warbler (Acrocephalus sechellensis)

Abstract

We describe the development and initial application of a semiautomated parentage testing system in the Seychelles warbler (Acrocephalus sechellensis). This system used fluorescently labelled primers for 14 polymorphic microsatellite loci in two multiplex loading groups to genotype efficiently over 96% of the warbler population on Cousin island. When used in conjunction with the program cervus, this system provided sufficient power to assign maternity and paternity within the Seychelles warbler, despite the complications associated with its cooperative breeding system and a relatively low level of genetic variation. Parentage analyses showed that subordinate ‘helper’ females as well as the dominant ‘primary’ females laid eggs in communal nests, indicating that the Seychelles warbler has an intermediate level of female reproductive skew, in between the alternative extremes of helper‐at‐the‐nest and joint nesting systems. Forty‐four per cent of helpers bred successfully, accounting for 15% of all offspring. Forty per cent of young resulted from extra‐group paternity.

Factors affecting the distribution of haemosporidian parasites within an oceanic island

“…DNA was extracted from blood using a modified salt method (Richardson et al, 2001). The molecular 181 technique described by Griffiths et al (1998) their host specificities in other parts of their distributions to evaluate if generalist lineages globally 278 act in the same way on Tenerife.…”

Altruism and infidelity among warblers

“…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 3 . 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 6 , making their relatedness to the father less reliable.…”

“…We studied the provisioning behaviour (feeds given per hour) of 21 colour-ringed female subordinates. Reproductive sharing and high levels of extra-pair paternity occur in this species 6 ; we therefore assessed parentage and genetic relatedness by using microsatellite DNA markers 8 . Subordinate parents (that is, subordinates who had also produced a nestling in the helped nest) always provisioned and were excluded from subsequent analysis (nǃ8).…”

Testosterone, cuckoldry risk and extra–pair opportunities in the Seychelles warbler

“…Although warblers can breed independently in their first year, a lack of suitable independent breeding opportunities drives some individuals into becoming subordinates within their own territory (Komdeur et al 1995). In groups consisting of adult primary and subordinate males, within-group paternity is nearly always gained by the primary male (Richardson et al 2001). Furthermore, extra-group paternity (EGP) is high (40%) and is always gained by primary males (Richardson et al 2001).…”

“…In groups consisting of adult primary and subordinate males, within-group paternity is nearly always gained by the primary male (Richardson et al 2001). Furthermore, extra-group paternity (EGP) is high (40%) and is always gained by primary males (Richardson et al 2001). To minimize paternity loss, primary males guard their females intensively during their fertile period and expel intruding males aggressively from the territory (Komdeur et al 1999).…”