Inter-annual and body topographic consistency in the plumage bacterial load of Great tits

Plumage bacteria may play an important role in shaping the life histories of birds. However, to design suitable experiments to examine causal relationships between plumage bacteria and the fitness of host birds, natural variation in plumage bacterial communities needs to be better understood.We examined within-individual consistency of plumage bacterial contamination in Great Tits (Parus major), comparing different body regions (ventral vs. dorsal) and comparing contamination between years. Numbers of free-living and attached bacteria and the species richness of feather-degrading bacterial assemblages were studied using flow cytometry and ribosomal intergenic spacer analysis (RISA). Numbers of both types of bacteria were higher on dorsal than on ventral feathers. Numbers of free-living, but not attached, bacteria on the two body regions were highly positively correlated. There was also a strong within-individual correlation between numbers of attached bacteria during the same breeding stages in different years. These results suggest that, despite variation in absolute levels of feather bacterial loads between years and different body regions, sampling individual birds can provide reliable estimates of relative levels of bacterial contamination, as long as sampling time and body region are carefully standardized.Las bacterias del plumaje pueden jugar un papel importante en el moldeamiento de las historias de vida de las aves. Sin embargo, para diseñar un experimento adecuado que examine la relación efecto causa entre las bacterias del plumaje y el éxito de las aves hospederas, se necesita entender mejor la variación natural de la comunidad de bacterias en el plumaje. Examinamos la consistencia en la contaminación de bacterias dentro de los individuos de Parus major, comprando diferentes regiones del cuerpo (ventral vs dorsal) y comparando contaminación entre años. Números de bacterias viviendo libremente y adheridas y la riqueza de especies del ensamble de bacterias degradadoras de plumas fueron estudiadas usando citometria de flujo y análisis ribosomal intergenetico espaciado (RISA). Números de ambos tipos de bacterias fueron más elevados en el dorso que en las plumas ventrales. Números de bacterias viviendo libremente, pero no las adheridas, en las regiones del cuerpo estuvieron altamente y positivamente correlacionados. También hubo una fuerte correlación dentro del individuo entre los números de bacterias adheridos durante el mismo estado reproductivo en años diferentes. Estos resultados sugieren que a pesar de la variación absoluta en los niveles de las cargas de bacterias del plumaje entre años y diferentes regiones corporales, individuos muestreados pueden proporcionar estimativos consistentes en los niveles relativos de contaminación bacteriana, siempre y cuando los tiempos de muestreo y la región corporal sean cuidadosamente estandarizados.The Estonian Science Foundation (grant number ETF8566 to R.M. and ETF8376 to V.T.), the Estonian Ministry of Education and Science (target-financing project number SF0180004s09) and the European Regional Development Fund (Center of Excellence FIBIR).http://onlinelibrary.wiley.com/journal/10.1111/(ISSN)1557-9263

Variación en el ensamble de bacterias de las plumas con relación al color del plumaje de la hembra de parus major

Microorganisms are known to play an important role in shaping the life histories of animals. Recent studies have proposed that the coloration of birds’ plumage could reflect individual quality through associations with feather-degrading bacteria. However, few studies have explored such relationships. We studied breeding female Great Tits (Parus major) during nest building and chick rearing to explore associations between bacteria inhabiting their yellow chest feathers and feather coloration. Specifically, we used flow cytometry and ribosomal intergenic spacer analysis (RISA), respectively, to study the densities of all free-living and attached bacteria and the phylotypic richness of feather-degrading bacterial assemblages. We used chroma (color saturation) as a measure of feather coloration. During chick rearing but not during nest building, the female’s chroma was negatively related to the phylotypic richness of feather-degrading bacteria. Also, a seasonal change in the density of attached bacteria associating with individual birds was negatively associated with change in chroma over the same period. These findings suggest that conspicuous coloration of female Great Tits may reflect the numbers and character of bacteria inhabiting feathers.Se sabe que los microorganismos juegan un rol importante en modelar las historias de vida de los animales. Estudios recientes han propuesto que la coloración del plumaje de las aves podría reflejar la calidad individual indicando la asociación con bacterias que degradan las plumas. Sin embargo, pocos estudios han explorado estas relaciones. Estudiamos hembras reproductivas de Parus major durante la construcción del nido y la cría de pichones para explorar asociaciones entre bacterias que habitan sus plumas amarillas del pecho y la coloración de las plumas. Específicamente, usamos citometría de flujo y análisis ribosomal de espaciadores intergénicos (RISA por sus siglas en Inglés), respectivamente, para estudiar las densidades de todas las bacterias libres y ligadas y la riqueza filotípica de los ensambles de bacterias que degradan las plumas. Empleamos croma (saturación del color) como una medida de coloración de la pluma. Durante la cría de los pichones pero no durante la construcción del nido, la croma de la hembra estuvo negativamente relacionada a la riqueza filotípica de las bacterias que degradan las plumas. Además, el cambio estacional en la densidad de las bacterias ligadas asociadas con aves individuales estuvo negativamente asociado con los cambios en la croma a lo largo del mismo período. Estos resultados sugieren que la coloración conspicua de las hembras de P. major puede reflejar la cantidad y el carácter de las bacterias que habitan las plumas.The Estonian Science Foundation (grant number ETF8566 to RM), the Estonian Ministry of Education and Science (target-financing project number 0180004s09), and the European Union through the European Regional Development Fund (Center of Excellence FIBIR).http://www.ucpressjournals.com/reprintInfo.asp.am2013ab201

Host dispersal shapes the population structure of a tick-borne bacterial pathogen

Birds are hosts for several zoonotic pathogens. Because of their high mobility, especially of longdistance migrants, birds can disperse these pathogens, affecting their distribution and phylogeography. We focused on Borrelia burgdorferi sensu lato, which includes the causative agents of Lyme borreliosis, as an example for tick-borne pathogens, to address the role of birds as propagation hosts of zoonotic agents at a large geographical scale. We collected ticks from passerine birds in 11 European countries. B. burgdorferi s.l. prevalence in Ixodes spp. was 37% and increased with latitude. The fieldfare Turdus pilaris and the blackbird T. merula carried ticks with the highest Borrelia prevalence (92 and 58%, respectively), whereas robin Erithacus rubecula ticks were the least infected (3.8%). Borrelia garinii was the most prevalent genospecies (61%), followed by B. valaisiana (24%), B. afzelii (9%), B. turdi (5%) and B. lusitaniae (0.5%). A novel Borrelia genospecies "Candidatus Borrelia aligera" was also detected. Multilocus sequence typing (MLST) analysis of B. garinii isolates together with the global collection of B. garinii genotypes obtained from the Borrelia MLST public database revealed that: (a) there was little overlap among genotypes from different continents, (b) there was no geographical structuring within Europe, and (c) there was no evident association pattern detectable among B. garinii genotypes from ticks feeding on birds, questing ticks or human isolates. These findings strengthen the hypothesis that the population structure and evolutionary biology of tick-borne pathogens are shaped by their host associations and the movement patterns of these hosts.Peer reviewe

Interaction of climate change with effects of conspecific and heterospecific density on reproduction

We studied the relationship between temperature and the coexistence of great titParus majorand blue titCyanistes caeruleus, breeding in 75 study plots across Europe and North Africa. We expected an advance in laying date and a reduction in clutch size during warmer springs as a general response to climate warming and a delay in laying date and a reduction in clutch size during warmer winters due to density-dependent effects. As expected, as spring temperature increases laying date advances and as winter temperature increases clutch size is reduced in both species. Density of great tit affected the relationship between winter temperature and laying date in great and blue tit. Specifically, as density of great tit increased and temperature in winter increased both species started to reproduce later. Density of blue tit affected the relationship between spring temperature and blue and great tit laying date. Thus, both species start to reproduce earlier with increasing spring temperature as density of blue tit increases, which was not an expected outcome, since we expected that increasing spring temperature should advance laying date, while increasing density should delay it cancelling each other out. Climate warming and its interaction with density affects clutch size of great tits but not of blue tits. As predicted, great tit clutch size is reduced more with density of blue tits as temperature in winter increases. The relationship between spring temperature and density on clutch size of great tits depends on whether the increase is in density of great tit or blue tit. Therefore, an increase in temperature negatively affected the coexistence of blue and great tits differently in both species. Thus, blue tit clutch size was unaffected by the interaction effect of density with temperature, while great tit clutch size was affected in multiple ways by these interactions terms.Peer reviewe

Data from: Insulin-like growth factor 1 and life-history evolution of passerine birds

1. Natural selection has generated a diversity of ways in which vertebrates allocate their resources between fundamental life-history traits. The availability of possible evolutionary trajectories of these traits is limited by various genetic, physiological, and phylogenetic constraints. This causes trade-offs due to shared resource pools for, or genetic linkage of, competing traits. The majority of these trade-offs are mediated by hormones and create the variability of phenotypes that can be observed in nature. 2. Insulin-like growth factor 1 (IGF-1) is an evolutionarily conserved peptide, which has been shown to be essential in the regulation of body size, the pattern of reproductive investment and lifespan across a broad taxonomic range of model species in laboratory and domesticated conditions. However, studies addressing corresponding evolutionary hypotheses on a broader scale and in free-living vertebrates are very rare. 3. In this phylogenetic comparative study on free-living passerines (Passeriformes), we explore the way in which plasma IGF-1 levels underlie the evolution of body size and demographic fitness correlates (clutch size, egg weight, lifespan). 4. We showed firstly that IGF-1 levels were positively associated with the body size of passerines, although smaller birds had larger IGF-1-mediated investment into building up their body faster. IGF-1 levels were negatively associated with lifespan of passerines, and more so in birds with smaller body weight. Finally, IGF-1 levels were negatively associated with clutch size in heavier species, and positively associated with egg weight in species with higher body weight and longer duration of parental care. The pattern was opposite in species with smaller body weight and shorter duration of parental care. 5. The described evolutionary framework indicates that variation in IGF-1 levels can be regarded as an important mechanism that may underlie life-history evolution in passerines. IGF-1 could act as a physiological link mediating the inter-regulatory growth–reproduction–lifespan “life-history triangle” on the pace-of-life continuum. Interestingly, body weight and investment into parental care have likely imposed a constraining effect on the IGF-1-mediated co-evolution of demographic fitness traits, such as lifespan or reproductive investment. This has limited the availability of adaptive pathways via which those traits could evolve as passerines diversified

Lodjak_2017_IGF-1_data_Dryad

Passerine (63 species) data for life-history traits and IGF-1 level

Cricket-full data Proc R Soc B

Cricket-full data Proc R Soc