When choosing your sexual partner, the milhirinhas ((serinus serinus), a very abundant bird species in Portugal, prefer yellow males with ultraviolet rays, reveals a study carried out by a team of researchers from the University of Coimbra (UC) over the past five years.
Considering the fact that, in this type of birds, the mating process is led exclusively by the female, the results of the study already published in Behavioral Ecology and Sociobiology, a leading journal in the field of ecology and behavior evolution, «are surprising because even now, it was thought that the presence of ultraviolet did not interfere with the choice of females in species with colorations based on carotenoids.
The conclusions show that the reflected ultraviolet contains decisive information for the choice of the pair in millheirinhas.
Therefore, the coloration of males evolved due to the females' preference for the color yellow, but with ultraviolet light», observes Paulo Gama Mota, coordinator of the study.
To assess the importance of the presence of UV in the choice of females, the researchers carried out two studies with millet captured in a natural environment.
In a first phase, after measuring the coloration of males using spectrophotometric techniques, the females were placed individually in compartments before two males with different levels of coloration. The choice fell on the most colorful males.
Subsequently, the researchers blocked the presence of ultraviolet in these males (by placing filters in the compartment and varnish on the feathers, which prevented the observation of UV) and found that «the milletiras no longer made any distinction when choosing their sexual partner, that is, , males have lost their power of attraction. From the point of view of sexual selection, it is very interesting to verify that the choice of a partner involves mechanisms as sophisticated as the presence of ultraviolet light», sustains the also professor at the Faculty of Science and Technology of the University of Coimbra (FCTUC).
In the next phase of the study, which resulted in two master's theses, the team will try to understand why male coloration is such an important factor in mating of milletinhas and what is its impact on reproductive behavior.
Author: Cristina Pinto (Press Office – University of Coimbra)
Science in the Regional Press – Ciência Viva
Comments