Evidence for pathogen infection influencing age dependent pairing in the crimson rosella (<em>Platycercus elegans</em>) – young and infected males rarely mate — ASN Events

Evidence for pathogen infection influencing age dependent pairing in the crimson rosella (Platycercus elegans) – young and infected males rarely mate (#470)

Justin R Eastwood 1 , Mathew Berg , Raoul Ribot 1 , Ken Walder 1 , Kate Buchanan 1 , Andrew Bennett 2
  1. Deakin University, Geelong
  2. Centre for Integrative Ecology , Deakin University, Geelong

In many species, breeding pairs exhibit an array of social behaviours that create the opportunity for direct pathogen transmission to themselves and their offspring. Avoiding partners that are infected would therefore seem beneficial, particularly if the pathogen is highly transmissible and virulent. Beak and Feather Disease Virus (BFDV) is one of the most common and highly infectious pathogens to infect parrots. We studied BFDV in three populations of the crimson rosella (Platycercus elegans; a common parrot of Australia), to test the age-dependency of viral infections, and how infections were distributed across breeding pairs and their offspring. This species exhibits delayed plumage maturation, with subadult (1st year) birds lacking the gaudy red plumage of adults. We observed more non-infected breeding pairs than expected by chance, but found a lower than expected frequency of cases where both sexes within a pair were infected. Infected males were rarely observed breeding, but infected females were often paired with uninfected males. Moreover, we found clear age-dependent pairing in males; unlike females, sub-adult males rarely bred and females never paired with a male younger than themselves. In both sexes, prevalence and viral load were lower in older age classes, but patterns of infection among pairs remained consistent when accounting for age-dependent infection. In addition, parental infection status did not explain nestling infection status, suggesting that other infection routes (e.g. from the nest material) are likely in this system. The rarity of finding infected breeding males could be explained by female choice for non-infected males or by the reduced competitiveness of infected males. We discuss the potential for age-related infection by parasites or other pathogens to mediate age-dependent mating. Additionally, our findings have implications for managing outbreaks BFDV and other pathogens in endangered species.