Avian malaria affects lekking behaviour of blue-crowned manakins
Submitted by Johan on 22 April 2016.Get the paper!
This research shows the effects of avian malaria, caused by the infection of protozoans of the genus Plasmodium on the social behavior of Blue-crowned manakins. The birds of this species are well-known for holding exhibitions of dances to females during the breeding season. These dances are performed on dance perches located within traditional locations where the males congregate. Such aggregates, which may have between one and seven adult males are called “leks”. Females do not participate in the lek, visiting them only occasionally, usually during the breeding season.
We found that the overall prevalence of avian malaria (% of infected individuals / total individuals sampled) was 47% in blue-crowned manakin. However, the prevalence of malaria varied within each range. In leks with a high prevalence of avian malaria, vocalization rates and dancing were lower compared to the ranges where the prevalence was lower. In leks with a high prevalence of malaria, uninfected males vocalized and danced more compared to those infected. Such effects on host individuals are possibly related to the highly pathogenic strains of Plasmodium found in the blood of these individuals.
In addition, we have observed that female blue-crowned manakins first choose the leks that they will visit. Generally, the most popular leks are the bigger ones with a larger number of adult males. When visiting these big leks, females can compare the performance of adult males during their dance displays, and assess how well coordinated these individuals are. Within the larger leks, females visit adult males that dance, vocalize, and interact with each other the most. Given that uninfected males are more active (they dance and sing more), and that females the visit them more, it is possible that vocalisation and dancing behaviours are trustworthy indicators showing how healthy an individual is, thus aiding the female's choice during visits to the dance perches.
Mariane Bosholn, Author
Read the paper online: http://onlinelibrary.wiley.com/doi/10.1111/jav.00864/abstract
Video showing display by blue-crowned manakin male (filmed by Marina Anciães)