Dietary carotenoids have been proposed to boost immune system and antioxidant functions in vertebrate animals, but studies aimed at testing these physiological of often failed find support. Here we subject yellow canaries (Serinus canaria), which possess high levels their tissue, white recessive canaries, a knockdown mutation that results very low tissue carotenoids, oxidative pathogen challenges. Across diverse measures performance, detect no differences between carotenoid-rich...

A fragment of the mitochondrial cytochrome b gene avian malaria (genera Haemoproteus and Plasmodium) was amplified from blood samples 12 species passerine birds genera Acrocephalus, Phylloscopus Parus. By sequencing 478 nucleotides obtained fragments, we found 17 different haplotypes or Plasmodium among bird investigated. Only one out in more than host species, this exception being a haplotype detected both blue tits (Parus caeruleus) great major). The phylogenetic tree which constructed...

Recently, several polymerase chain reaction (PCR)–based methods for detection and genetic identification of haemosporidian parasites in avian blood have been developed. Most these considerably higher sensitivity compared with traditional microscope-based examinations smears. These new already had a strong impact on aspects research parasites. In this study, we present nested PCR approach, building previously published method, which has significantly improved performance. We compare the...

We approach the field of stress immunology from an ecological point view and ask: why should a heavy physical workload, for example as result high reproductive effort, compromise immune function? argue that immunosuppression by neuroendocrine mechanisms, such hormones, during workload is adaptive, consider two different ultimate explanations immunosuppression. First, several authors have suggested system suppressed to reallocate resources other metabolic demands. In our view, this hypothesis...

Chronic malaria shortens telomeres infections are assumed to cause little damage the host, but is this true? Migrant birds can pick up various species of parasite while overwintering in tropics. After initial acute malaria, migrant great reed warblers, which nest Sweden and overwinter Africa, asymptomatically infected for life. Asghar et al. discovered that these cryptically laid fewer eggs were less successful at rearing healthy offspring than uninfected birds. Furthermore, had...

Abstract We studied the phylogeny of avian haemosporidian parasites, Haemoproteus and Plasmodium , in a number African resident European migratory songbird species sampled during spring autumn northern Nigeria. The parasites was constructed through sequencing part their mitochondrial cytochrome b gene. found eight parasite lineages, five three infecting multiple host species. Thus, 44% 18 haemospiridian lineages this study were detected more than one species, indicating that sharing is...

1. Recently, there has been much interest in physiological trade‐offs between parasite resistance and fitness‐related traits such as secondary sexual characters or reproductive effort. More specifically it suggested that (i) energetically costly activities may suppress the immune system (ii) this immunosuppression is caused by defences competing with other bodily demands for scarce resources, e.g. energy. 2. The possibility was investigated of an based trade‐off humoral (antibody‐based)...

Life-history theory predicts that increased current reproductive effort should lead to a fitness cost. This cost of reproduction may be observed as reduced survival or future reproduction, and caused by temporal suppression immune function in stressed hard-working individuals. In birds, consideration the costs incubating eggs has largely been neglected favour brood rearing. We manipulated incubation demand two breeding seasons (2000 2001) female common eiders (Somateria mollissima) creating...

Traditional explanations for the negative fitness consequences of parasitism have focused on direct pathogenic effects infectious agents. However, because high selection pressure by parasites, immune defences are likely to be costly and trade off with other fitness–related traits, such as reproductive effort. In a field experiment, we immunized breeding female flycatchers non–pathogenic antigens (diphtheria–tetanus vaccine), which excluded in order test activated defence hosts' investment...

Immune defences are undoubtedly of great benefit to the host, reducing impact infectious organisms. However, mounting immune responses also entails costs, which may be measured by inducing against artificial infections. We injected common eider (Somateria mollissima) females with three different non-pathogenic antigens, sheep red blood cells (SRBC), diphtheria toxoid and tetanus toxoid, early in their incubation period. In group that mounted a humoral response SRBC, return rate was only 27%,...

A total of 1,794 migrating birds trapped at a coastal site in southern Sweden were sampled for detection Campylobacter spp. All isolates phenotypically identified as jejuni and subset those non-C. to the species level by PCR-based techniques. C. was found 5.0% birds, lari 5.6%, coli 0.9%. An additional 10.7% tested infected with hippurate hydrolysis-negative that not level. The prevalence differed significantly between ecological guilds birds. Shoreline-foraging feeding on invertebrates...

A fundamental assumption of theories the ecology and evolution inducible defences is that protective responses to attacks by parasites or predators should not only have benefits, but also costs. The vertebrate immune system far best studied example an defence, yet little known about costs response, especially in natural populations. To test if response per se costly, we induced antibody female blue tits, Parus caeruleus , immunising them with human diphtheria–tetanus vaccine, compared their...

1. We have used molecular methods to unravel a remarkable diversity of parasite lineages in long-term population study great reed warblers Acrocephalus arundinaceus that was not foreseen from traditional microscopic examination blood smears. This includes eight Haemoproteus and 10 Plasmodium which most probably represent good biological species. 2. Contrary expectation, the relative frequency seemed change over 17-year period we found no effects parasites on male secondary sexual ornament...

To study the relative importance of factors with direct and indirect effects on male fitness in polygynous Great Reed Warbler, Acrocephalus arundinaceus, I investigated characteristics both males territories relation to annual lifetime breeding success. Male harem size number offspring recruits (i.e., young surviving age) were repeatable between years. analyzed success using stepwise multiple regressions by testing for significant trends (over five years) pairwise correlations each territory...

Abstract We investigated the degree of geographical shifts transmission areas vector‐borne avian blood parasites ( Plasmodium , Haemoproteus and Leucocytozoon ) over ecological evolutionary timescales. Of 259 different parasite lineages obtained from 5886 screened birds sampled in Europe Africa, only two were confirmed to have current resident bird species both areas. used a phylogenetic approach show that belonging genera rarely change area these are restricted one fauna long time span not...

The immunocompetence handicap hypothesis proposes that testosterone (T)‐dependent sexual signals are honest indicators of male health or genetic quality because only high‐quality males able to withstand the obligate effects T‐induced immunosuppression. In birds, basic assumption T suppresses immune function is equivocal, and physiological mechanisms underlying immunosuppression remain be investigated. We explored proximate pathways in song sparrows (Melospiza melodia) by treating captive...

Abstract One group of commonly found parasites in birds, for which fitness consequences and effects on life history traits have been much debated are Haemosporidian blood parasites. In a long term study population great reed warblers Acrocephalus arundinaceus Sweden, previous studies shown that the their chronic phase during breeding season infected non-infected birds similar. present study, we quantified parasite intensity (parasitemia) 718 adults sampled between 1987 1998 three most common...

The DNA‐fingerprinting technique was used to find the true pedigrees and detect overall genetic similarity between mates of great reed warblers (Acrocephalus arundinaceus) at an isolated breeding site in Sweden. study covered 4 yr preceded by 3 when almost all adults nestlings area had been banded. DNA fingerprinting revealed that putative father sired 97% young (N = 455). mate's similarity, as proportion bands shared restriction fragment length polymorphism (RFLP) patterns, high compared...

Malaria parasites are a widespread and species-rich group infecting many wild populations of mammals, birds reptiles. Studies on humans have demonstrated that genetic factors play key role in the susceptibility outcome malaria infections. Until present study, it has not been examined whether variation hosts is important for infections natural avian populations. We investigated associations between major histocompatibility complex (MHC) genes prevalence three different ( Haemoproteus...