Search results for "106"
showing 10 items of 6128 documents
Alianzas antiembalse y luchas hidroepistemológicas. Los retos de la gestión colectiva del agua en el Río Grande, Málaga, España
2018
En este artículo analizamos las luchas epistemológicas y retos que ha tenido el movimiento social en la subcuenca del río Grande frente a los diversos proyectos modernizadores que intentan transferir el agua rural hacia la ciudad de Málaga. El primero asociado a la construcción de un gran embalse y el segundo con la modernización de los sistemas de riego tradicionales. Concluimos que el reto está en desenmascarar el régimen de verdad que respalda los proyectos de modernidad hidráulica, reivindicar los derechos de uso y control colectivos del agua y así generar procesos de apropiación comunitaria para la defensa del río como un bien socio-ambiental, económico-cultural y político-epistemológi…
Psychometric properties and factor structure of the Satisfaction with Life Scale in an elderly Portuguese retirees students sample
2017
El objetivo principal de este estudio ha sido analizar las propie- dades psicométricas de la escala de Satisfacción con la Vida (SWLS) en una muestra de 363 estudiantes jubilados pertenecientes a varias universidades portuguesas. El 70% de los participantes eran mujeres frente a un 30% de hombres, con una media de edad de 67 años (SD = 7.59) y un rango de edad comprendido entre 48 y 90 años. Se realizó un Análisis Factorial Ex- ploratorio con R Commander y un Análisis Factorial Confirmatorio con Amos 18.0. El modelo que obtuvo un mejor ajuste estaba compuesto por un único factor. El índice de consistencia interna de la escala en su conjun- to fue de .777. En cuanto a la validez concurrente,…
Revista complutense de educación
2020
Este artículo se encuentra disponible en la siguiente URL: https://revistas.ucm.es/index.php/RCED/article/view/63205/4564456553652 Introducción. Las normas legales se fundamentan en unos principios y valores que las instituciones escolares asumen y expresan en las diferentes dimensiones de su planificación y, sobre todo, en su acción. En aras de hallar los valores comunes que se supone impregnan los hechos educativos de cualquier escuela española, nos hemos decantado por realizar un estudio axiológico del currículo básico, que es el texto legal que orienta los desarrollos curriculares autonómicos y, en última instancia, de cada centro y equipo docente. Presentamos un estudio axiológico del …
Aposematism in the burying beetle? Dual function of anal fluid in parental care and chemical defence
2017
Burying beetles (Nicrophorus vespilloides) bear distinctive and variable orange-black patterning on their elytra and produce an anal exudate from their abdomen when threatened. During breeding, the anal exudates contribute to the antimicrobial defence of the breeding resource. We investigated whether the anal exudates also provide a responsive chemical defence, which is advertised to potential avian predators by the beetle’s orange and black elytral markings. We found that that the orange-black elytral markings of the burying beetle are highly conspicuous for avian predators against range of backgrounds, by using computer simulations. Using bioassays with wood ants, we also showed that the …
Colour alone matters : no predator generalization among morphs of an aposematic moth
2018
Local warning colour polymorphism, frequently observed in aposematic organisms, is evolutionarily puzzling. This is because variation in aposematic signals is expected to be selected against due to predators' difficulties associating several signals with a given unprofitable prey. One possible explanation for the existence of such variation is predator generalization, which occurs when predators learn to avoid one form and consequently avoid other sufficiently similar forms, relaxing selection for monomorphic signals. We tested this hypothesis by exposing the three different colour morphs of the aposematic wood tiger moth, Arctia plantaginis, existing in Finland to local wild-caught predato…
The price of safety: food deprivation in early life influences the efficacy of chemical defence in an aposematic moth
2018
Aposematism is the combination of a primary signal with a secondary defence that predators must learn to associate with one another. However, variation in the level of defence, both within and between species, is very common. As secondary defences influence individual fitness, this variation in quality and quantity requires an evolutionary explanation, particularly as it may or may not correlate with variation in primary signals. The costs of defence production are expected to play a considerable role in generating this variation, yet studies of the cost of chemical defence have focused on species that sequester their defences, while studies in species that produce them de novo are scarce. …
An aposematic colour‐polymorphic moth seen through the eyes of conspecifics and predators – Sensitivity and colour discrimination in a tiger moth
2018
Although predation is commonly thought to exert the strongest selective pressure on coloration in aposematic species, sexual selection may also influence coloration. Specifically, polymorphism in aposematic species cannot be explained by natural selection alone. Males of the aposematic wood tiger moth (Arctia plantaginis) are polymorphic for hindwing coloration throughout most of their range. In Scandinavia, they display either white or yellow hindwings. Female hindwing coloration varies continuously from bright orange to red. Redder females and yellow males suffer least from bird predation. White males often have higher mating success than yellow males. Therefore, we ask whether females ca…
Multimodal Aposematic Defenses Through the Predation Sequence
2021
Aposematic organisms warn predators of their unprofitability using a combination of defenses, including visual warning signals, startling sounds, noxious odors, or aversive tastes. Using multiple lines of defense can help prey avoid predators by stimulating multiple senses and/or by acting at different stages of predation. We tested the efficacy of three lines of defense (color, smell, taste) during the predation sequence of aposematic wood tiger moths (Arctia plantaginis) using blue tit (Cyanistes caeruleus) predators. Moths with two hindwing phenotypes (genotypes: WW/Wy = white, yy = yellow) were manipulated to have defense fluid with aversive smell (methoxypyrazines), body tissues with a…
Multiple modalities in insect warning displays have additive effects against wild avian predators
2019
Allocation to different components of defence has been suggested as an explanation for the existence of multiple aposematic morphs in a single population. We tested whether there are trade-offs between warning colouration and chemical defence or whether these have an additive effect when combined, using blue tits (Cyanistes caeruleus) as predators and the polymorphic wood tiger moth (Arctia plantaginis) as prey. We used artificial edible models (with and without the moths’ defensive fluids) with paper wings whose colour and pattern properties matched those of real moths. When the models were presented sans defensive fluids or when the fluids were presented without colour cues, we detected n…
Transparency reduces predator detection in mimetic clearwing butterflies
2019
International audience; Predation is an important selective pressure and some prey have evolved conspicuous warning signals that advertise unpalatability (i.e. aposematism) as an antipredator defence. Conspicuous colour patterns have been shown effective as warning signals, by promoting predator learning and memory. Unexpectedly, some butterfly species from the unpalatable tribe Ithomiini possess transparent wings, a feature rare on land but common in water, known to reduce predator detection.We tested if transparency of butterfly wings was associated with decreased detectability by predators, by comparing four butterfly species exhibiting different degrees of transparency, ranging from ful…