Feather mites (Arachnida: Acari: Astigmata) feed mainly on secretions of the uropygial gland of birds. Here, we use analyses corrected for phylogeny and body size to show that there is a positive correlation between the size of this gland and mite abundance in passerine birds at an interspecific level during the breeding season, suggesting that the gland mediates interactions between mites and birds. As predicted on the basis of hypothesized waterproofing and antibiotic functions of uropygial gland secretions, riparian/marsh bird species had larger glands and higher mite loads than birds living in less mesic terrestrial environments. An unexpected pattern was a steeper relationship between mite load and gland size in migratory birds than in residents. If moderate mite loads are beneficial to a host but high loads detrimental, this could create complex selection regimes in which gland size influences mite load and vice versa. Mites may exert selective pressures on gland size of their hosts that has resulted in smaller glands among migratory bird species, suggesting that smaller glands may have evolved in these birds to attenuate a possible detrimental effect of feather mites when present in large numbers.

Feather mites are arthropods that live on or in the feathers of birds, and are among the commonest avian ectosymbionts. However, the nature of the ecological interaction between feather mites and birds remains unclear, some studies reporting negative eff ects of feather mites on their hosts and others reporting positive or no eff ects. Here we use a large dataset comprising 20 189 measurements taken from 83 species of birds collected during 22 yr in 151 localities from seven countries in Europe and North Africa to explore the correlation between feather mite abundance and body condition of their hosts. We predicted that, if wing-dwelling feather mites are parasites, a negative correlation with host body condition should be found, while a mutualistic interaction should yield positive correlation. Although negative relationships between feather mite abundance and host body condition were found in a few species of birds, the sign of the correlation was positive in most bird species (69%). Th e overall eff ect size was only slightly positive (r ϭ 0.066). Th e eff ect of feather mite abundance explained Ͻ 10% of variance in body condition in most species (87%). Results suggest that feather mites are not parasites of birds, but rather that they hold a commensalistic relationship where feather mites may benefi t from feeding on uropygial gland secretions of their hosts and birds do not seem to obtain a great benefi t from the presence of feather mites.

Understanding why host species differ so much in symbiont loads and how this depends on ecological host and symbiont traits is a major issue in the ecology of symbiosis. A first step in this inquiry is to know whether observed differences among host species are species-specific traits or more related with host-symbiont environmental conditions. Here we analysed the repeatability (R) of the intensity and the prevalence of feather mites to partition within- and among-host species variance components. We compiled the largest dataset so far available: 119 Paleartic passerine bird species, 75,944 individual birds, ca. 1.8 million mites, seven countries, 23 study years. Several analyses and approaches were made to estimate R and adjusted repeatability (Radj) after controlling for potential confounding factors (breeding period, weather, habitat, spatial autocorrelation and researcher identity). The prevalence of feather mites was moderately repeatable (R = 0.26–0.53; Radj = 0.32–0.57); smaller values were found for intensity (R = 0.19–0.30; Radj = 0.18–0.30). These moderate repeatabilities show that prevalence and intensity of feather mites differ among species, but also that the high variation within species leads to considerable overlap among bird species. Differences in the prevalence and intensity of feather mites within bird species were small among habitats, suggesting that local factors are playing a secondary role. However, effects of local climatic conditions were partially observed for intensity.

Los conocimientos científicos están presentes en los currículos de todos los niveles educativos. Sin embargo, son pocas las investigaciones orientadas a saber qué contenidos se enseñan, cómo lo hacen, qué aprende el alumnado… en la etapa de educación infantil. En este trabajo estudiamos la percepción que tienen los futuros maestros sobre la enseñanza de las ciencias que se realiza en las aulas de segundo ciclo de esta etapa. A partir de sus vivencias en las prácticas de enseñanza, unos estudiantes del Grado de Educación Infantil han respondido a un cuestionario elaborado para conocer mejor la realidad educativa que estamos estudiando. Los resultados ponen de manifiesto el escaso tratamiento de algunos contenidos y la ausencia de actividades claves para aprender ciencias en estas edades. Por último, se realizan algunas consideraciones en relación con la formación del profesorado, inicial y en ejercicio.

RESUMEN • Este trabajo analiza las relaciones entre la formación, la investigación en didáctica y la práctica docente del profesorado de ciencias de secundaria. La muestra no probabilística está formada por 55 profesores de secundaria. La metodología elegida es de tipo mixto (cuantitativo-cualitativo) y utiliza tres instrumentos complementarios: un cuestionario, un protocolo de observación en el aula y una entrevista. Los resultados de los cuestionarios muestran dos tipos de formación en didáctica de las ciencias: activa y estándar. Las observaciones y las entrevistas ponen de manifiesto la existencia de dos tipologías docentes con grandes diferencias entre ellas en lo referente a estrategias de enseñanza, uso de materiales de aprendizaje innovadores, gestión de aula y utilización de las TIC, y permiten afirmar que los cursos puntuales cambian poco la práctica docente.PALABRAS CLAVE: formación del profesorado; didáctica de las ciencias; práctica docente; conocimiento didáctico del contenido.ABSTRACT • This work analyzes the relationships between teacher training, research in science education and the teaching practice of science Spanish in-service teachers of secondary education. The non-probabilistic sample consist of 55 teachers. The mixed methodology chosen (quantitative-qualitative) uses three complementary instruments: a questionnaire, a classroom observation protocol and an interview. The questionnaires show two types of teacher training in science education: active and standard. The observation of daily teachers' classroom practice and the interviews show different ways of teaching with large differences between both groups relating to teaching strategies, use of innovative learning materials, classroom management and use of ICT and allow to affirm that occasional teacher training of short-term courses have little impact in teaching practice.