Plumage colour predicts dispersal propensity in male pied flycatchers

CANAL, DAVID; CAMACHO, CARLOS; ABRIL-COLÓN, INMACULADA; POTTI, JAIME; PÉREZ-RODRÍGUEZ, LORENZO

BEHAVIORAL ECOLOGY AND SOCIOBIOLOGY

SPRINGER

Año: 2018 vol. 72

0340-5443

Abstract: Melanin-based colouration of tegument structures may be related to variability in the expression of certain strategies or behaviours within a species, including the propensity to disperse. This is because melanin synthesis may be physiologically linked to certain behaviours and personality traits, as proposed by the hypothesis of the pleiotropy in the melanocortin system (HPMS). During a 28-year period (1988?2015), we studied the melanin-based dorsal colouration of male pied flycatchers (Ficedula hypoleuca) in relation to natal dispersal movements between contrasting (pine and oak) habitats. In addition, the relationship between tonic immobility (TI), a measure of individual fearfulness towards predators, and plumage colour was examined using a shorter time series. Consistent with HPMS, males? dispersal propensity was related to their plumage colour, with the blackest individuals being more likely to disperse into a new habitat to breed. Blacker males remained for longer in TI than lighter ones. The positive relationship between plumage melanisation and TI might result from the pleiotropic effect of the melanocortin system on glucocorticoid-mediated stress and fearfulness responses as well as on eumelanin synthesis. This study provides solid empirical support for the HPMS in relation to natal dispersal behaviour. Significance statement: Individual behaviour can be integrated with other phenotypic traits via the pleiotropic effects of some biochemical pathways. Recent research has shown connections between melanin-based colouration, personality and certain life history traits. However, the relationship between colouration and natal dispersal?a critical phase of life?has received comparatively little attention. We studied this link in the pied flycatcher, a small bird in which males exhibit considerable variation in dorsal plumage colour, ranging from brown to black. By following individuals from fledging to settlement, we show that males with a higher percentage of black feathers are more likely to disperse into novel environments than lighter males. Furthermore, we found an association between plumage melanisation and individual fearfulness to predators, possibly due to the shared pathways of melanin synthesis and stress responses. Our results highlight the potential of the interplay between melanin production and individual behaviour to explain the maintenance of colour variability in natural populations.