Loss of sexual dimorphism is associated with loss of lekking behavior in the green manakinXenopipo holochora

Abstract

Manakins (Pipridae) are well know for elaborate male sexual displays and ornate plumage coloration, both of which are thought to have evolved as a consequence of lekking breeding, the prevalent mating system in the family. Less attention has been paid to a handful of ‘drab’ manakin species, in which sexual dimorphism appears to be reduced or absent. Using character reconstruction, we show that these ‘exceptions to the rule’ represent phylogenetically independent cases of losses in sexual dimorphism, and as such could provide a focal group to investigate the link between changes in morphology and in life history (e.g. mating system). We take a first step in this direction by focusing on two subspecies of the putatively monomorphic green manakin Xenopipo holochlora to formally confirm that the species is sexually monomorphic in size and plumage color and test the prediction that sexual monomorphism is associated with the loss of lekking behavior in this species. Our results show that size dimorphism is present but limited in the green manakin, with substantial overlap in male and female morphometric measures, and that sexes are largely monochromatic (including from an avian perspective), despite marked coloration differences between subspecies. Behavioral observations indicate that males do not form leks and do not engage in elaborate sexual displays, that there is no stable pair bond formation, and that females provide parental care alone. These findings are consistent with the idea that changes in mating behavior may have driven changes in morphology in Pipridae, and we encourage similar studies on other drab manakins to better understand this relationship.

Broad‐scale variation in sexual dichromatism in songbirds is not explained by sex differences in exposure to predators during incubation

“…One explanation for our results is the traditional Darwinian view that sexual selection is the primary driver of dichromatism, which would hence largely vary with mating system. However, in support of the traditional Darwinian view, there is recent evidence that loss of lekking can lead to loss of dichromatism (Ribeiro et al 2015). Although this effect was stronger in exposed patches, the direction of the effect was similar in concealed patches and only detailed further studies can show whether this difference is an important finding or an unimportant fluke.…”

“…Previous studies of the relationship between dichromatism and mating system have suggested that the effect of lekking on dichromatism can be complex, with selection for bright coloration driven by female choice but crypsis in males selected by the risk of displaying at traditional sites that should easily be detected by predators (Bleiweiss 1992). However, in support of the traditional Darwinian view, there is recent evidence that loss of lekking can lead to loss of dichromatism (Ribeiro et al 2015).…”

An atypical mating system in a neotropical manakin

“…Lekking is considered an ancestral trait in the monophyletic Pipridae clade, with a single origin in the group's common ancestor, and very few deviations from lek mating have been documented for manakins [24]. One case is that of green manakins (genus Xenopipo), in which the sexes are largely monochromatic and males have lost lekking behaviour [42]. In one species of another genus, the helmeted manakin Antilophia galeata, no evidence has been found of the typical lek arena configuration.…”

Characterization and Biomimcry of Avian Nanostructured Tissues

“…Males in the genus Lepidothrix display exceptionally bright colours on their crown and rump feathers (figure 1), such as ultrawhites, vibrant blues, golds, and iridescent opal-like colours (Kirwan and Green, 2011;this study). Despite considerable interest in the function and evolution of coloration within this family of birds (Endler and Thery, 1996;Doucet et al, 2007;Ribeiro et al, 2015), characterization of their coloration and examinations of colour production mechanisms have primarily focussed on non-iridescent blues and greens (Saranathan et al, 2012). Here, we examined and compared the coloration and colour production mechanisms across plumage ornaments of four Lepidothrix species, primarily focussing on two species with iridescent plumage but, unusually, white or pale coloured background appearance.…”