Use of anthropogenic material affects bird nest arthropod community structure: influence of urbanisation, and consequences for ectoparasites and fledging success

Nests are a critically important factor in determining the breeding success of many species of birds. Nevertheless, we have surprisingly little understanding of how local environment helps shape materials used in construction, how this differs among related species using similar nest sites, or if materials used directly or indirectly influence the numbers of offspring successfully reared. We also have little understanding of any potential links between nest construction and the assemblage of invertebrates which inhabit the nest and in particular, with ectoparasites. We addressed these questions by monitoring the success rates of nest-box using Blue Tits Cyanistes caeruleus and Great Tits Parus major, from rural, urban greenspace and urban garden settings. We collected used nests, identified arthropods present, and measured the proportions of highly processed anthropogenic materials used in their construction. Some 25% of Great Tit nest materials were of an anthropogenic source and this was consistent across habitats, while Blue Tits used little (1-2%) except in gardens (~16%), suggesting that Great Tits preferentially sought out these materials. In fledged nests, increasing use of anthropogenic material was associated with lower general arthropod diversity and ectoparasite predator abundance (Blue Tits only) but higher levels of Siphonapterans (fleas). Higher arthropod diversity was associated with lower flea numbers, suggesting that increased diversity played a role in limiting flea numbers. No direct link was found between breeding success and either anthropogenic material usage, or arthropod diversity and abundance. However, breeding success declined with increasing urbanisation in both species and increased with nest weight in Blue Tits. The interplay between urbanisation and bird ecology is complex; our work shows that subtle anthropogenic influences may have indirect and unexpected consequences for urban birds

Interspecific variation in the relationship between clutch size, laying date and intensity of urbanization in four species of hole-nesting birds

The increase in size of human populations in urban and agricultural areas has resulted in considerable habitat conversion globally. Such anthropogenic areas have specific environmental characteristics, which influence the physiology, life history, and population dynamics of plants and animals. For example, the date of bud burst is advanced in urban compared to nearby natural areas. In some birds, breeding success is determined by synchrony between timing of breeding and peak food abundance. Pertinently, caterpillars are an important food source for the nestlings of many bird species, and their abundance is influenced by environmental factors such as temperature and date of bud burst. Higher temperatures and advanced date of bud burst in urban areas could advance peak caterpillar abundance and thus affect breeding phenology of birds. In order to test whether laying date advance and clutch sizes decrease with the intensity of urbanization, we analyzed the timing of breeding and clutch size in relation to intensity of urbanization as a measure of human impact in 199 nest box plots across Europe, North Africa, and the Middle East (i.e., the Western Palearctic) for four species of hole-nesters: blue tits (Cyanistes caeruleus), great tits (Parus major), collared flycatchers (Ficedula albicollis), and pied flycatchers (Ficedula hypoleuca). Meanwhile, we estimated the intensity of urbanization as the density of buildings surrounding study plots measured on orthophotographs. For the four study species, the intensity of urbanization was not correlated with laying date. Clutch size in blue and great tits does not seem affected by the intensity of urbanization, while in collared and pied flycatchers it decreased with increasing intensity of urbanization. This is the first large-scale study showing a species-specific major correlation between intensity of urbanization and the ecology of breeding. The underlying mechanisms for the relationships between life history and urbanization remain to be determined. We propose that effects of food abundance or quality, temperature, noise, pollution, or disturbance by humans may on their own or in combination affect laying date and/or clutch size

Proprioceptive contribution of postural control as assessed from very slow oscillations of the support in healthy humans

International audienceMaintaining erect human posture depends on graviceptive information. This can come from at least of three origins: vestibular, visual and somaesthetic. We hypothesize here that subject's use proprioception rather than visual or vestibular cues for their control of upright body posture and this even when subjects stand on a tilting body support surface. In order to find experimental evidence for this hypothesis, we exclude in our experiments visual cues (eyes close) and by keeping frequency and amplitude of the tilt stimulus so low that it would be below the detection threshold for vestibular semi-circular canal stimuli. The orientations of body segments were analysed during various phases of the perturbation cycle. Segmental stabilisations were defined in terms of both the global anchoring index calculated during the whole perturbation cycle and an appropriate sequential anchoring index calculated during various phases in the perturbation cycle. We show that subjects tend to align their bodies with the space vertical and do so better for their heads than for their upper bodies and lower bodies. A further finding is that stabilisation is related to the tilt stimulus in the form that it is minimal at the turning points of the tilt, where peak tilt velocity is minimal with the sinusoidal stimulus used. These finding suggest first that proprioceptive cues are predominant in the control of body orientation in quasi-static condition and second that the head and trunk stabilisation strategies used as the basis of postural control depend on the properties of the moving support

Impaired vertical postural control and proprioceptive integration deficits in Parkinson’s disease

International audienceThe aim of the present study was to investigate how the orientation and stabilization components of postural control may be affected as the result of the impaired proprioceptive integration possibly occurring in Parkinson's disease. To determine the proprioceptive contribution to postural control, parkinsonian patients and control subjects were asked to maintain vertical stance while very slow sinusoidal oscillations were being applied in the lateral and antero-posterior planes to the platform on which they were standing. The amplitude and frequency of their movements were kept below the semicircular canal perception threshold. Data were collected with the ELITE automatic motion analyzer and the two postural components (orientation and segmental stabilization) were analyzed at head and trunk levels while the subjects were performing the task with their eyes open and closed. The results show that 1) the parkinsonian groups' performances were affected in terms of both the postural orientation and stabilization components in comparison with the control group, 2) the use of vision improved the parkinsonian patients' postural performances, and 3) both parkinsonian patients and control subjects achieved better postural performances when antero-posterior perturbations rather than lateral perturbations were applied to the foot support. These results suggest that Parkinson's disease is associated with proprioceptive impairment, which may be an important factor contributing to these patients' postural deficits. On the basis of these results, the visual dependence observed in parkinsonian patients is re-defined as an adaptive strategy partly compensating for the impaired proprioception

Axial rotation in Parkinson's disease

International audienceTo investigate the ability of patients with Parkinson's disease to perform a rotation around the longitudinal axis of the body. Three questions were raised. Is body rotation impaired in Parkinson's disease? Is there a level of the kinematic chain from the head to the foot at which the impairment is more severe? Is the deficit related to the general slowness of movement in Parkinson's disease

Extreme short-term environmental constraints do not update internal models of action as assessed from motor imagery in adults

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Strength of the perception action coupling in human body discrimination tasks

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Body schema building during childhood and adolescence: A neurosensory approach

International audienceIn order to perceive and act in its environment, the individual's body and its interactions with the sensory and social environment are represented in the brain. This internal representation of the moving body segments is labeled the body schema. Throughout life, body schema develops based on the sensory information used by the moving body and by its interactions with the environment including other people. Internal representations including body schema and representations of the outside world develop with learning and actions throughout ontogenesis and are constantly updated based on different sensory inputs. The aim of this review is to present some concepts and experimental data about body schema, internal representations and updating process during childhood and adolescence, as obtained using a neurosensory approach. From our developmental studies, it was possible to explore the slow maturation of the sensorimotor representations by examining the anticipatory control. By manipulating proprioceptive and visual information, which are at the heart of the construction of body schema, we wished to highlight notable differences between adolescents and young adults on both a postural and perceptual level, which confirms the late maturation of multisensory integration for central motor control

Motor expertise for typing impacts lexical decision performance

The massive shift in writing habits calls for a better understanding of the possible consequences of typing practice on language processing, including reading. To assess a possible impact of typing knowledge on word recognition, we built a set of words and pseudowords differing by their ratio of bimanual transitions between letters, an index of typing difficulty for experts. An effect of typing difficulty was observed in expert participants who were actually typing the items and not in a control group of hunt-and-peck typists. We then tested whether word recognition, measured with the task of lexical decision, was impacted by the typing difficulty of words. We found that lexical decision latencies varied as a function of typing difficulty, but differently for experts and non-experts. The effect was mostly driven by pseudowords. This suggests that motor representations built during the practice of typing have a collateral effect on visual recognition processes. The implications for education are discussed

DEVELOPMENT OF ACTION REPRESENTATION DURING ADOLESCENCE AS ASSESSED FROM ANTICIPATORY CONTROL IN A BIMANUAL LOAD-LIFTING TASK

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