A longitudinal study of age‐related changes inHaemoproteusinfection in a passerine bird

Abstract

Blood parasites such as malaria and related haemosporidians commonly infect vertebrate species including birds. Understanding age-specifi c patterns of parasite infections is crucial for quantifying the fi tness consequences of parasitism for hosts and for understanding parasite transmission dynamics. We analyzed longitudinal and cross-sectional infection data in house martins Delichon urbica , a migratory bird suff ering from intense haemosporidian infection. We separated within-from among-individual eff ects of age on prevalence. Our results showed that the probability of blood parasite infection increased as individual house martins aged. We also showed that the prevalence of infection decreased with age at last reproduction when controlling for age, showing a selective disappearance of infected birds from the population (i.e. selection). Th e estimated eff ect of age on prevalence was underestimated two-to three-fold if not accounting for such selection. Th is study highlights the importance of taking among-individual heterogeneity in the capacity to fi ght a disease into account because such heterogeneity can mask age-related patterns of infection. Th ese fi ndings emphasize the relevance of considering within-and among-individual patterns of infection in order to understand parasite-induced mortality and the potential for parasite transmission.

Rainfall at African wintering grounds predicts age‐specific probability of haemosporidian infection in a migratory passerine bird

“…There was a higher haemosporidian prevalence in young than in experienced birds, probably due to selective disappearance of infected birds (Marzal et al 2016). There was a higher haemosporidian prevalence in young than in experienced birds, probably due to selective disappearance of infected birds (Marzal et al 2016).…”

“…Thus we were able to assign the age of individuals accurately, assuming un-ringed birds to be yearlings at first capture that had originated from outside the study area, and assuming that disappearance of ringed breeders from the colony indicated mortality rather than dispersal (Marzal et al 2016). Adult House Martins were captured and identified with numbered metal rings.…”

“…Because previous studies have revealed the importance of age for haemosporidian infection and migratory ecology in House Martins (Marzal et al 2016, L opez-Calder on et al 2017a, we also tested for differences in the probability of blood infection and winter quarters according to ageclass. genera Haemoproteus, Plasmodium and Leucozytozoon).…”

Importance of infection of haemosporidia blood parasites during different life history stages for long‐term reproductive fitness of collared flycatchers

“…Furthermore, lineages act as independent species (Nilsson et al 2016), show spatial heterogeneity within a local environment (Wood et al 2007), and can have different infection strategies (Nilsson et al 2016). However, before inferences can be made on the effect that each parasite lineage has on host population dynamics, we must first determine the timing of parasite transmission , Asghar et al 2011, because age-dependent parasite infections can influence the strength of selection imposed on a host population, as well as effect estimates of parasite-mediated fitness costs (Marzal et al 2016). However, before inferences can be made on the effect that each parasite lineage has on host population dynamics, we must first determine the timing of parasite transmission , Asghar et al 2011, because age-dependent parasite infections can influence the strength of selection imposed on a host population, as well as effect estimates of parasite-mediated fitness costs (Marzal et al 2016).…”

Wintering areas predict age‐related breeding phenology in a migratory passerine bird

“…Briefly, breeding dispersal is negligible in our study sites with less than 0.1% of breeding individuals (i.e. ≥ first year of age) among the more than 10 000 adults ringed in the study population during more than 20 yr ever being recorded at another colony in the same or subsequent years (Marzal et al ). Moreover, age at first reproduction occurred at the age of one year for the majority of individuals since all but one of more than 500 individuals marked as nestlings were recruited as first‐year breeding adults.…”