Evolution of female promiscuity in Passerides songbirds

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 R 2 ≤ 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 pre-mating 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. Electronic supplementary material The online version of this article (10.1186/s12862-019-1493-1) contains supplementary material, which is available to authorized users.

Sperm Morphology and Male Age in Black-Throated Blue Warblers, an Ecological Model System

“…The degree of among-male variation in sperm total length is somewhat higher than expectations based on the extrapair paternity rate of the species (measured CV am 2.1; value of CV am associated with 43% extra-pair young, 1.43, using the calculator provided in [48]). Age-related changes in sperm total length may be partly responsible for this higher-than-expected between-male variation (though note that there is substantial unexplained variation in the relationship, such that our observed value is not extreme [4,48]).…”

“…The degree of among-male variation in sperm total length is somewhat higher than expectations based on the extrapair paternity rate of the species (measured CV am 2.1; value of CV am associated with 43% extra-pair young, 1.43, using the calculator provided in [ 48 ]). Age-related changes in sperm total length may be partly responsible for this higher-than-expected between-male variation (though note that there is substantial unexplained variation in the relationship, such that our observed value is not extreme [ 4 , 48 ]). Average total sperm length for black-throated blue warblers is similar to other wood-warblers (average for black-throated blue warblers, 247.64 ± 5.11 μm; average for other wood-warblers in [ 4 ], 222.78 ± 41.08 μm; average for oscine passerines in [ 4 ], 147.82 ± 71.9 μm).…”

Heritability of the extra-pair mating behaviour of the pied flycatcher in Western Siberia

“…However, it is often very difficult to decide which system is the main scheme of interrelationships between individuals ( Ford, 1983 ), since some bird species comprise both purely monogamous and predominantly polygynous populations ( De Santo et al, 2003 ). Therefore, it seems quite natural today that the hypotheses explaining the EPC evolution ( Lifjeld et al, 2019 ; Brouwer & Griffith, 2019 ) largely overlap with those explaining the polygamy evolution ( Parker & Birkhead, 2013 ), since ultimately both EPC and polygamy are multiple mating.…”

“…The mechanisms leading to the frequent occurrence of EPO in socially monogamous couples are strongly debated ( Halliday & Arnold, 1987 ; Sherman & Westneat, 1988 ; Jennions & Petrie, 2000 ; Arnqvist & Kirkpatrick, 2005 , 2007 ; Kokko, Jennions & Brooks, 2006 ; Griffith, 2007 ; Kempenaers, 2007 ; Eliassen & Jørgensen, 2014 ; Forstmeier et al, 2014 ). Most hypotheses explaining the evolution of extra-pair reproduction suggest selective and adaptive scenarios for the origin and persistence of extra-pair mating behaviour (for review, Eliassen & Jørgensen, 2014 ; Forstmeier et al, 2014 ; Lifjeld et al, 2019 ; Brouwer & Griffith, 2019 ). Selection acts on phenotypes, and it only has evolutionary consequences when fitness differences among individuals relate directly to genetic differences.…”

Temporal dynamics of competitive fertilization in social groups of red junglefowl (Gallus gallus) shed new light on avian sperm competition

“…For example, the juxtaposition of avian and insect sperm competition dynamics has helped clarify the differential roles of sperm size and numbers in these clades [35]. The importance of birds is in part owing to field studies of extra-pair copulation and extra-pair paternity in socially monogamous species [8,12,29,[36][37][38][39] and the wealth of information on the reproductive biology of the domestic fowl, Gallus domesticus, and other domestic galliforms, which have informed the development of mechanistic models of sperm competition [30,40,41]. As in most other species of birds, female fowl typically ovulate one egg on each successive day of the laying cycle, with fertilization occurring shortly after ovulation [42].…”