CNRS Mechanical Adaptation and Evolution

Paris, France

CNRS Mechanical Adaptation and Evolution

Paris, France
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Bojados M.,Aix - Marseille University | Herbin M.,CNRS Mechanical Adaptation and Evolution | Jamon M.,Aix - Marseille University
Behavioural Brain Research | Year: 2013

The study compared the motor performance of adult C57Bl/6J mice previously exposed to a 2G gravity environment during different periods of their development. 12 mice were housed in a large diameter centrifuge from the conception to Postnatal day 10 (P10). Another group of 10 mice was centrifuged form P10 to P30, and a third group of 9 mice was centrifuged from conception to P30. Their gait parameters, and kinematics of joint excursions were compared with 11 control mice, at the age of 2 months using a video-radiographic apparatus connected to a motorized treadmill. The mice that returned to Earth gravity level at the age of P10 showed a motor pattern similar to control mice. At variance the two groups that were centrifuged from P10 to P30 showed a different motor pattern with smaller and faster strides to walk at the same velocity as controls. On the other hand all the centrifuged mice showed significant postural changes, particularly with a more extended ankle joint, but the mice centrifuged during the whole experimental period differed even more. Our results showed that the exposure to hypergravity before P10 sufficed to modify the posture, suggesting that postural control starts before the onset of locomotion, whereas the gravity constraint perceived between P10 and P30 conditioned the tuning of quadruped locomotion with long term consequences. These results support the existence of a critical period in the acquisition of locomotion in mice. © 2013 Elsevier B.V. All rights reserved.

Languille S.,CNRS Mechanical Adaptation and Evolution | Aujard F.,CNRS Mechanical Adaptation and Evolution | Pifferi F.,CNRS Mechanical Adaptation and Evolution
Behavioural Brain Research | Year: 2012

The data are inconsistent about the ability of dietary omega-3 fatty acids to prevent age-associated cognitive decline. Indeed, most clinical trials have failed to demonstrate a protective effect of omega-3 fatty acids against cognitive decline, and methodological issues are still under debate. In contrast to human studies, experiments performed in adult rodents clearly indicate that omega-3 fatty acids supplement can improve behavioural and cognitive functions. The inconsistent observations between human and rodent studies highlight the importance of the use of non-human primate models. The aim of the present study was to address the impact of omega-3 fatty acids (given in the form of dietary fish oil) on exploratory activity, emotional status and spatial reference memory in the aged mouse lemur, a non-human primate. Aged animals fed fish oil exhibited decreased exploratory activity, as manifested by an increase in the latency to move and a reduced distance travelled in an open-field. The fish oil-supplemented animals exhibited no change in the anxiety level, but they were more reactive to go into the dark arms of a light/dark plus-maze. In addition, we found that fish oil supplementation did not significantly improve the spatial memory performance in the Barnes maze task. This study demonstrated for the first time that a fish oil diet initiated late in life specifically modifies the exploratory behaviour without improving the spatial memory of aged non-human primates. Omega-3 fatty acid supplementation may be effective when started early in life but less effective when started at later ages. © 2012 Elsevier B.V.

Salmon S.,CNRS Mechanical Adaptation and Evolution
Applied Soil Ecology | Year: 2016

Three field studies have been performed, in order to assess changes in the composition of soil animal communities, soil physical and chemical features and mineralization processes with Norway spruce (Picea abies, L.) phases of the forest cycle. These field studies were conducted in three sites that differed in the acidity level of their bedrock (acidic, sub-acidic, and basic). The influence of exposure, through modifying microclimatic conditions, was also taken in consideration by comparing north and south exposures at each site. The data issued from each of these studies have already been published separately, and the aim of the present paper is to confront the three series of data in order to assess: 1) The general trend of changes in soil invertebrate communities, humus forms and mineralization processes with the age of spruce; 2) The impact of the type of bedrock and exposure on these changes.The results indicate that deep modifications occurred in animal communities, humus forms and soil functioning among clearing, regeneration and mature tree stands. The changes consist in an increase of Humus Index and the density of mites, especially oribatids, with a decrease in mineralization rate and animal diversity, from clearing to mature stands.Regeneration stands occupy an intermediate level as regards soil features but cumulates highest densities of most groups, highest levels of zoological diversity and mineralization activity. This higher level of richness and functional activity in regeneration stands could be explained by a more heterogeneous habitat in this phase of the forest cycle. Our results thus support the hypothesis that forest dynamics drives soil functioning and diversity, at least during the phase of intense growth of trees.The evolution of humus forms and animal communities along the developmental phases of forest stands were considerably more pronounced in south-facing sites than in north-facing sites. Unexpectedly, no increase in animal diversity was observed from the more to the less acidic bedrock. Suggestions for forest management are proposed. © 2017 Elsevier B.V.

Herrel A.,CNRS Mechanical Adaptation and Evolution | Bonneaud C.,French National Center for Scientific Research
Journal of Experimental Biology | Year: 2012

Amphibians are ideal taxa with which to investigate the effects of climate change on physiology, dispersal capacity and distributional ranges as their physiological performance and fitness is highly dependent on temperature. Moreover, amphibians are among the most endangered vertebrate taxa. Here we use the tropical clawed frog, Xenopus tropicalis, as a model system to explore effects of temperature on locomotor performance. Our analyses show that locomotion is thermally sensitive, as illustrated by significant effects of temperature on terrestrial exertion capacity (time until exhaustion) and aquatic burst speed (maximal burst swimming velocity and maximal burst swimming acceleration capacity). Exertion performance measures had relatively lower temperature optima and narrower performance breadth ranges than measures of burst speed. The narrow 80% performance breadths confirm predictions that animals from stable environments should display high thermal sensitivity and, combined with the divergent temperature optima for exertion capacity and burst speed, underscore the vulnerability of tropical species such as X. tropicalis to even relatively small temperature changes. The temperature sensitivity of locomotor performance traits in X. tropicalis suggests that tropical ectotherms may be impacted by predicted changes in climate. © 2012. Published by The Company of Biologists Ltd.

Stevens V.M.,CNRS Mechanical Adaptation and Evolution | Stevens V.M.,University of Liège | Turlure C.,CNRS Mechanical Adaptation and Evolution | Baguette M.,CNRS Mechanical Adaptation and Evolution
Biological Reviews | Year: 2010

Dispersal has recently gained much attention because of its crucial role in the conservation and evolution of species facing major environmental changes such as habitat loss and fragmentation, climate change, and their interactions. Butterflies have long been recognized as ideal model systems for the study of dispersal and a huge amount of data on their ability to disperse has been collected under various conditions. However, no single 'best' method seems to exist leading to the co-occurrence of various approaches to study butterfly mobility, and therefore a high heterogeneity among data on dispersal across this group. Accordingly, we here reviewed the knowledge accumulated on dispersal and mobility in butterflies, to detect general patterns. This meta-analysis specifically addressed two questions. Firstly, do the various methods provide a congruent picture of how dispersal ability is distributed across species? Secondly, is dispersal species-specific? Five sources of data were analysed: multisite mark-recapture experiments, genetic studies, experimental assessments, expert opinions, and transect surveys. We accounted for potential biases due to variation in genetic markers, sample sizes, spatial scales or the level of habitat fragmentation. We showed that the various dispersal estimates generally converged, and that the relative dispersal ability of species could reliably be predicted from their relative vagrancy (records of butterflies outside their normal habitat). Expert opinions gave much less reliable estimates of realized dispersal but instead reflected migration propensity of butterflies. Within-species comparisons showed that genetic estimates were relatively invariable, while other dispersal estimates were highly variable. This latter point questions dispersal as a species-specific, invariant trait. © 2010 Cambridge Philosophical Society.

Canale C.I.,CNRS Mechanical Adaptation and Evolution | Henry P.-Y.,CNRS Mechanical Adaptation and Evolution
Functional Ecology | Year: 2011

Resource-limiting conditions impose a change in the energetic distribution between competing physiological processes. Over the past decade there has been increasing interest in trade-offs between the immune system and competing energy-consuming life-history traits. However, the trade-offs with energy saving mechanisms, such as heterothermy, have received limited attention. The goal of this study is to determine how daily heterothermy expression could be adjusted to counterbalance the energetic requirements for the activation of the immune system depending on food availability (ad libitum vs. 40% calorie restriction) in a heterothermic primate, the Grey Mouse Lemur (Microcebus murinus). On the day of the immune challenge, torpor was removed through the onset of fever, inducing a thermogenic cost. On the days following, food-restricted individuals returned to deep torpor (i.e. energy saving) whereas those fed ad libitum continued to skip torpor for at least three additional days. The rapid return to an energy saving state in food restricted individuals raises new questions on the relationship between body temperature and immunocompetence. We suggest that (i) hyperthermia provides the first line of defence against pathogens, which is a trait common to all organisms, (ii) but that hypothermia may also protect the host by inhibiting pathogen proliferation. © 2010 The Authors. Functional Ecology © 2010 British Ecological Society.

Canale C.I.,CNRS Mechanical Adaptation and Evolution | Henry P.-Y.,CNRS Mechanical Adaptation and Evolution
Climate Research | Year: 2010

As ecosystems undergo global changes, there is increasing interest in understanding how organisms respond to changing environments. Recent evidence drawn from available vertebrate studies suggests that most of the phenotypic responses to climate change would be due to plasticity. We hypothesize that organisms that have evolved in unpredictable environments inform us about the mechanisms of phenotypic plasticity which provide an adaptive response to climate instability. As climate changes increase climatic hazards, these resilience mechanisms are expected to spread within species, populations and communities. We review studies that have demonstrated the importance of phenotypic plasticity in different life-history traits in overcoming climate uncertainty. We focus on organisms from unstable, recurrently energetically restrictive environments which possess a variety of morphological, physiological and/or behavioural adaptations to climate-driven selective pressures. First, we treat plastic morphological changes in response to fluctuating food availability. Adjustment of morphometric traits and/or organ size to energy supply would be essential in harsh environments. Second, we review the role of flexible energy-saving mechanisms, such as daily torpor, hibernation and energy storage, in overcoming climate-driven energetic shortages. Lastly, we address the role of plastic modulation of reproduction in fine-tuning the energy allocation to offspring production according to environmental conditions, with an emphasis on opportunistic breeding. Overall, we predict that species (or genotypes) possessing these efficient physiological mechanisms of resilience to unpredictable water and food fluctuations will be selectively advantaged in the face of increasing climatic instability. © Inter-Research 2010.

Ponge J.-F.,CNRS Mechanical Adaptation and Evolution
Ecology and Evolution | Year: 2013

The present text exposes a theory of the role of disturbances in the assemblage and evolution of species within ecosystems, based principally, but not exclusively, on terrestrial ecosystems. Two groups of organisms, doted of contrasted strategies when faced with environmental disturbances, are presented, based on the classical r-K dichotomy, but enriched with more modern concepts from community and evolutionary ecology. Both groups participate in the assembly of known animal, plant, and microbial communities, but with different requirements about environmental fluctuations. The so-called "civilized" organisms are doted with efficient anticipatory mechanisms, allowing them to optimize from an energetic point of view their performances in a predictable environment (stable or fluctuating cyclically at the scale of life expectancy), and they developed advanced specializations in the course of evolutionary time. On the opposite side, the so-called "barbarians" are weakly efficient in a stable environment because they waste energy for foraging, growth, and reproduction, but they are well adapted to unpredictably changing conditions, in particular during major ecological crises. Both groups of organisms succeed or alternate each other in the course of spontaneous or geared successional processes, as well as in the course of evolution. The balance of "barbarians" against "civilized" strategies within communities is predicted to shift in favor of the first type under present-day anthropic pressure, exemplified among others by climate warming, land use change, pollution, and biological invasions. © 2013 The Authors. Ecology and Evolution.

Ponge J.-F.,CNRS Mechanical Adaptation and Evolution
Soil Biology and Biochemistry | Year: 2013

The present review was undertaken to add more information on the place taken by humus forms in plant-soil interactions. Three questions were asked: (i) are humus forms under the control of plant-soil relationships, (ii) are humus forms the main seat of these relationships, and (iii) can humus forms explain interactions between aboveground and belowground biodiversity. Some conflicting views about humped-back models of species richness may be resolved by considering a limited number of stable humus forms (here considered as ecosystem strategies) which should be treated separately rather than in a single model. Mull, moder and mor pathways are each characterized by a fine tuning between aboveground and belowground communities, the humus form (including litter) being the place where resonance between these communities takes place, both in functional and evolutionary sense. © 2012 Elsevier Ltd.

Marchal J.,CNRS Mechanical Adaptation and Evolution | Pifferi F.,CNRS Mechanical Adaptation and Evolution | Aujard F.,CNRS Mechanical Adaptation and Evolution
Annals of the New York Academy of Sciences | Year: 2013

Through its antioxidant, anticarcinogenic, and anti-inflammatory properties, resveratrol has become a candidate for drug development in the context of aging studies. Scientific evidence has highlighted its potential as a therapeutic agent for cardiovascular diseases and some cancers but also as an antiaging molecule. Resveratrol is thought to mimic the beneficial effects of chronic and moderate calorie restriction. Nevertheless, no study has demonstrated the prolongation of life span in healthy nonobese mammal models. This review summarizes recent findings on the effects of resveratrol on aging and life span in mammals. In our opinion, more studies should be performed to assess the effects of a chronic dietary intake of resveratrol in long-lived species close to humans, such as nonhuman primates. This will certainly generate more evidence about the ability of resveratrol to achieve the physiological benefits that have been observed in small mammal laboratory models and feature the eventual unwanted secondary effects that may occur under high levels of resveratrol. © 2013 New York Academy of Sciences.

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