The effect of habitat quality on the blood parasite assemblage in understorey avian insectivores in the Eastern Himalaya, India

Abstract

The anthropogenic alteration of natural habitats can modify interactions between various biotic and abiotic factors. The prevalence of avian blood parasites in free‐living host species in the tropics has shown contrasting patterns in altered landscapes. Here, we investigate these potential associations between understorey insectivorous bird species of the Eastern Himalayas and avian haemosporidians in primary and selectively logged forests. We describe patterns related to host–parasite associations, host life‐history traits and host specificity in primary and logged forests. Using parasite‐specific cytochrome‐b gene markers, we screened 545 individual birds from nine families, 33 genera and 57 species. Of these, 34.67% were infected with Leucocytozoon spp., 13.94% with Haemoproteus spp., 3.30% with Plasmodium spp. and 8.44% with co‐infections. We found that parasite prevalence did not change with logging; however, host specificity and life‐history traits did have associations with infection prevalence. We report a vertical stratification in genera‐specific infections driven by vector groups – upper canopy and midstorey foragers had high Leucocytozoon and Haemoproteus prevalence, respectively. In addition, species foraging in mixed‐species flocks showed increased infection risk with Leucocytozoon, whereas solitary foragers had a high prevalence of Plasmodium. This study also highlights that avian parasite lineages are genetically more distinct in primary forest than in logged forest plots. Although our study demonstrates no influence of selective logging on parasite prevalence, it does reflect a positive influence of host abundance and logged habitats on parasite diversity. Our work reveals valuable patterns in terms of phylospecificity and genetic variation in parasite assemblages. Further research with a focus on parasite intensity and vector abundance will help us to understand anthropogenic impacts on parasite transmission dynamics in Eastern Himalayan birds.