From helping to breeding – male choice in the southern anteater-chats Myrmecocichla formicivora.

• Dispersal choice is important in understanding population structure and dynamics. Here we examine male choice in the facultative cooperative breeding southern anteater-chat Myrmecocichla formicivora based on a four year study in South Africa. The sex ratio in our study population was male biased, with many males remaining philopatric. All groups consisted of one or more adult males associated with one adult female. We found a significant positive effect of auxiliary number on group productivity (both number of young fledged, and first year survival), while controlling for potentially confounding variables (territory and breeder identity). The majority of auxiliaries, 54%, were related to both birds in the breeding pair, with another 25% related to one member of the pair, and 21% related to neither of the breeders. There was no evidence of males floating within our study population, and it appears that if males lose their family due to mortality they join other groups as unrelated non-breeding auxiliaries rather than float. No aggression was observed between individual southern anteater-chats, and unrelated group members helped rear offspring in the group they had joined. Despite the presence of, and helping by unrelated group members there was very little evidence of breeding position inheritance (1/24 auxiliaries unrelated to the breeding female) or extra-pair paternity (2.4% of fledglings). This study suggests that the southern anteater-chat group structure arises through male philopatry due to a lack of breeding females and potentially high costs of living alone.

Ämnesord

NATURVETENSKAP  -- Biologi -- Evolutionsbiologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Evolutionary Biology (hsv//eng)

Nyckelord

Southern anteater-chat

cooperative breeding

social evolution

behavioural ecology

delayed dispersal

family living

Africa

Biologi med inriktning mot populationsbiologi

Biology with specialization in Population Biology

Publikations- och innehållstyp

vet (ämneskategori)

ovr (ämneskategori)