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Table 1 Predicted associations, and explanations, of each predictor variable with haemosporidian parasite prevalence and detection probability

From: Sex and nest type influence avian blood parasite prevalence in a high-elevation bird community

Parameter(s)

Predictor variable

Predicted

direction

Explanation

Occupancy probability (ψ)

Age

Q

For adult birds, prevalence of blood parasites decreases with age due to increased immunocompetence, until old age, in which immunosenescence occurs and is linked to a higher probability of infection [85]

 

Sex (female)

+

The cost of reproduction is higher in females, decreasing immunocompetence and making females more susceptible to haemosporidian infection [86].

 

BCI [mass (g): tarsus length (mm)]

−

Individuals in good condition have stronger immunocompetence and are better able to fight infections [89, 88]

 

Migration status

+

The energetic cost of migration increases with distance, and likely affects immunocompetence [90].

 

Nest type (open nest)

+

Open nests are more exposed to mosquito vectors compared to closed nests [91]

Detection probability (p)

PCR run

+

Differences in results of PCR runs may occur due to variation in parasitemia between samples, with higher parasitemia associated with higher probability of detection [92]

  1. Positive (+), negative (−), or quadratic (Q) predicted associations, and explanation, of each predictor variable for haemosporidian parasite occupancy probability (ψ; prevalence) and detection probability (p). BCI is body condition index defined as body mass:tarsus length. PCR is polymerase chain reaction