Evolution of female promiscuity in Passerides songbirds
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Date
2019-08-14
Journal Title
Journal ISSN
Volume Title
Publisher
BMC Ecology and Evolution
Abstract
Background: Female promiscuity is highly variable among birds, and particularly among songbirds. Comparative
work has identified several patterns of covariation with social, sexual, ecological and life history traits. However, it is
unclear whether these patterns reflect causes or consequences of female promiscuity, or if they are byproducts of
some unknown evolutionary drivers. Moreover, factors that explain promiscuity at the deep nodes in the
phylogenetic tree may be different from those important at the tips, i.e. among closely related species. Here we
examine the relationships between female promiscuity and a broad set of predictor variables in a comprehensive
data set (N = 202 species) of Passerides songbirds, which is a highly diversified infraorder of the Passeriformes
exhibiting significant variation in female promiscuity.
Results: Female promiscuity was highly variable in all major clades of the Passerides phylogeny and also among
closely related species. We found several significant associations with female promiscuity, albeit with fairly small
effect sizes (all R2 ≤ 0.08). More promiscuous species had: 1) less male parental care, particularly during the early
stages of the nesting cycle (nest building and incubation), 2) more short-term pair bonds, 3) greater degree of
sexual dichromatism, primarily because females were drabber, 4) more migratory behaviour, and 5) stronger premating
sexual selection. In a multivariate model, however, the effect of sexual selection disappeared, while the
other four variables showed additive effects and together explained about 16% of the total variance in female
promiscuity. Female promiscuity showed no relationship with body size, life history variation, latitude or cooperative
breeding.
Conclusions: We found that multiple traits were associated with female promiscuity, but these associations were
generally weak. Some traits, such as reduced parental care in males and more cryptic plumage in females, might
even be responses to, rather than causes of, variation in female promiscuity. Hence, the high variation in female
promiscuity among Passerides species remains enigmatic. Female promiscuity seems to be a rapidly evolving trait
that often diverges between species with similar ecologies and breeding systems. A future challenge is therefore to
understand what drives within-lineage variation in female promiscuity over microevolutionary time scales.
Description
Staff Publication
Keywords
Extrapair paternity,, Life history,, Mating system,, Pair bond,, Parental care,, Sexual selection
Citation
ifjeld, J.T., Gohli, J., Albrecht, T. et al. Evolution of female promiscuity in Passerides songbirds. BMC Evol Biol 19, 169 (2019). https://doi.org/10.1186/s12862-019-1493-1