Nayden Chakarov

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Parasite transmission strategies strongly impact host-parasite co-evolution and virulence. However, studies of vector-borne parasites such as avian malaria have neglected the potential effects of host relatedness on the exchange of parasites. To test whether extended parental care in the presence of vectors increases the probability of transmission from(More)
Blood parasite prevalence in two related warbler species (Acrocephalus arundinaceus and A. scirpaceus) was studied at three Bulgarian sites that differed mainly in altitude and weather. The prevalence of Haemoproteus, the most common parasite genus, was significantly lower at the highest altitude site (730 m above sea level, asl). Such a pattern was not(More)
1. The habitat heterogeneity (HHH) and individual adjustment (IAH) hypotheses are commonly proposed to explain a decrease in reproduction rate with increasing population density. Higher numbers of low-quality territories with low reproductive success as density increases lead to a decrease in reproduction under the HHH, while more competition at high(More)
BACKGROUND Intraguild predation (IGP) is widespread but it is often neglected that guilds commonly include many layers of dominance within. This could obscure the effects of IGP making unclear whether the intermediate or the bottom mesopredator will bear higher costs from the emergence of a new top predator. METHODOLOGY/PRINCIPAL FINDINGS In one of the(More)
Blood parasites of migrating yellow wagtails of two subspecies—Motacilla flava feldegg and Motacilla flava flava—were studied on a sample of 473 birds caught in spring and autumn periods in Bulgaria. We controlled eight “migration waves” (flocks captured in different evenings) of yellow wagtails for four parameters—average body mass, average fat level,(More)
Polymorphic genes involved in the conserved molecular signalling of circadian and circannual clocks may play important roles in governing the timing of breeding and dispersal and thereby affect fitness in vertebrates. However, relatively few studies have explored associations between phenological candidate genes and behaviour, and these are somewhat biased(More)
Parents may adapt their offspring sex ratio in response to their own phenotype and environmental conditions. The most significant causes for adaptive sex-ratio variation might express themselves as different distributions of fitness components between sexes along a given variable. Several causes for differential sex allocation in raptors with reversed(More)
The group of haemosporidian parasites is of general interest to basic and applied science, since several species infect mammals, leading to malaria and associated disease symptoms. Although the great majority of haemosporidian parasites appear in bird hosts, as in the case of Leucocytozoon buteonis, there is little genomic information about genetic aspects(More)
Intraguild predation (IGP) is a commonly recognized mechanism influencing the community structure of predators, but the complex interactions are notoriously difficult to disentangle. The mesopredator suppression hypothesis predicts that a superpredator may either simultaneously repress two mesopredators, restrain the dominant one and thereby release the(More)
Correlations between heterozygosity and fitness are frequently found but rarely well understood. Fitness can be affected by single loci of large effect which correlate with neutral markers via linkage disequilibrium, or as a result of variation in genome-wide heterozygosity following inbreeding. We explored these alternatives in the common buzzard, a raptor(More)