Multimodal signalling in estrildid finches: song, dance and colour are associated with different ecological and life‐history traits

Abstract

Sexual traits (e.g. visual ornaments, acoustic signals, courtship behaviour) are often displayed together as multimodal signals. Some hypotheses predict joint evolution of different sexual signals (e.g. to increase the efficiency of communication) or that different signals trade off with each other (e.g. due to limited resources). Alternatively, multiple signals may evolve independently for different functions, or to communicate different information (multiple message hypothesis). We evaluated these hypotheses with a comparative study in the family Estrildidae, one of the largest songbird radiations, and one that includes many model species for research in sexual selection and communication. We found little evidence for either joint evolution or trade-offs between song and colour ornamentation. Some negative correlations between dance repertoire and song traits may suggest a functional compromise, but generally courtship dance also evolved independently from other signals. Instead of correlated evolution, we found that song, dance and colour are each related to different socio-ecological traits. Song complexity evolved together with ecological generalism, song performance with investment in reproduction, dance with commonness and habitat type, whereas colour ornamentation was shown previously to correlate mostly with gregariousness. We conclude that multimodal signals evolve in response to various socio-ecological traits, suggesting the accumulation of distinct signalling functions.

The influence of developmental environment on courtship song in cactophilic Drosophila

“…Environmental conditions have the potential to affect both the content and the structure of signals and, thus, modify their quality (Boughman, ; Bro‐Jørgensen, ; Gomes et al ., ). In this regard, the sensory drive hypothesis emphasizes signal structure (Endler & Basolo, ) and focuses on how communication systems adapt to local environments (Boughman, ).…”

Independent evolution of song diversity and song motor performance in canaries, goldfinches and allies indicates clade‐specific trade‐offs in birdsong

“…Across Estrildid finches, aspects of song motor performance (syllable and trill rates, deviation of sound frequency relative to body size) are higher in species with longer nestling periods and, thus, with more parental care (Gomes et al. 2017), perhaps having evolved to signal male parental care ability (the good parent hypothesis; Hoelzer 1989), whereas higher syllable diversity is mostly found in species with smaller clutch sizes (Gomes et al. 2017), consistent with having evolved to attract multiple matings (e.g., the trade‐off hypothesis; Magrath and Komdeur 2003; Mitchell et al.…”

“…2017), perhaps having evolved to signal male parental care ability (the good parent hypothesis; Hoelzer 1989), whereas higher syllable diversity is mostly found in species with smaller clutch sizes (Gomes et al. 2017), consistent with having evolved to attract multiple matings (e.g., the trade‐off hypothesis; Magrath and Komdeur 2003; Mitchell et al. 2007).…”

Evolution of acoustic and visual signals in the antwrens of the tribe Formicivorini (Aves, Thamnophilidae)

“…Few studies have tested the TH in birds and they showed diverse results. Two studies found a trade-off between song complexity and plumage elaboration in cardueline finches (Badyaev and Weckworth, 2002) and in new world warblers (Laverde-R., 2017), whereas four studies did not find any trade-off between these signals in trogons (Ornelas et al, 2009), tanagers (Mason et al, 2014), estrildid finches (Gomes et al, 2017) and old-world orioles (Matysioková et al, 2017). Four other studies found a positive correlation between these signals in North American wood warblers (Shutler and Weatherhead, 1990), 123 species of North American oscines (Repentigny et al, 2000), Asian barbets (Gonzalez-Voyer et al, 2013) and 1023 species of songbirds (Webb et al, 2016).…”

“…Furthermore, only a few studies tested the TH considering the habitat conditions as a covariate (Gonzalez-Voyer et al, 2013;Mason et al, 2014;Laverde-R., 2017;Gomes et al, 2017). Therefore, the fundamental research goal of the proposed research was to assess the existence of a trade-off between acoustic and visual signals (TH), while simultaneously considering potential effects of habitat conditions (SDH) in a diverse group of Neotropical birds.…”