5,996 research outputs found
Conspicuous male coloration impairs survival against avian predators in Aegean wall lizards, Podarcis erhardii.
This is the final version of the article. It first appeared from Wiley via http://dx.doi.org/10.1002/ece3.1650Animal coloration is strikingly diverse in nature. Within-species color variation can arise through local adaptation for camouflage, sexual dimorphism and conspicuous sexual signals, which often have conflicting effects on survival. Here, we tested whether color variation between two island populations of Aegean wall lizards (Podarcis erhardii) is due to sexual dimorphism and differential survival of individuals varying in appearance. On both islands, we measured attack rates by wild avian predators on clay models matching the coloration of real male and female P. erhardii from each island population, modeled to avian predator vision. Avian predator attack rates differed among model treatments, although only on one island. Male-colored models, which were more conspicuous against their experimental backgrounds to avian predators, were accordingly detected and attacked more frequently by birds than less conspicuous female-colored models. This suggests that female coloration has evolved primarily under selection for camouflage, whereas sexually competing males exhibit costly conspicuous coloration. Unexpectedly, there was no difference in avian attack frequency between local and non-local model types. This may have arisen if the models did not resemble lizard coloration with sufficient precision, or if real lizards behaviorally choose backgrounds that improve camouflage. Overall, these results show that sexually dimorphic coloration can affect the risk of predator attacks, indicating that color variation within a species can be caused by interactions between natural and sexual selection. However, more work is needed to determine how these findings depend on the island environment that each population inhabits.This work was supported by a Biotechnology and Biological Sciences Research Council studentship, Magdalene College, Cambridge and the British Herpetological Society (K.L.A.M), and a Biotechnology and Biological Sciences Research Council and David Philips Research Fellowship (grant number BB/G022887/1) to M.S
Microhabitat choice in island lizards enhances camouflage against avian predators.
This is the final version of the article. It first appeared from Nature Publishing Group via http://dx.doi.org/10.1038/srep19815Camouflage can often be enhanced by genetic adaptation to different local environments. However, it is less clear how individual behaviour improves camouflage effectiveness. We investigated whether individual Aegean wall lizards (Podarcis erhardii) inhabiting different islands rest on backgrounds that improve camouflage against avian predators. In free-ranging lizards, we found that dorsal regions were better matched against chosen backgrounds than against other backgrounds on the same island. This suggests that P. erhardii make background choices that heighten individual-specific concealment. In achromatic camouflage, this effect was more evident in females and was less distinct in an island population with lower predation risk. This suggests that behavioural enhancement of camouflage may be more important in females than in sexually competing males and related to predation risk. However, in an arena experiment, lizards did not choose the background that improved camouflage, most likely due to the artificial conditions. Overall, our results provide evidence that behavioural preferences for substrates can enhance individual camouflage of lizards in natural microhabitats, and that such adaptations may be sexually dimorphic and dependent on local environments. This research emphasizes the importance of considering links between ecology, behaviour, and appearance in studies of intraspecific colour variation and local adaptation.This work was supported by a Biotechnology and Biological Sciences Research Council studentship, by the British Herpetological Society and Magdalene College, Cambridge (K.L.A.M), and by a Biotechnology and Biological Sciences Research Council and David Philips Research Fellowship (grant number BB/G022887/1) to M.
Intraspecific Colour Variation among Lizards in Distinct Island Environments Enhances Local Camouflage.
This is the final version of the article. It first appeared from PLOS via http://dx.doi.org/ 10.1371/journal.pone.0135241Within-species colour variation is widespread among animals. Understanding how this arises can elucidate evolutionary mechanisms, such as those underlying reproductive isolation and speciation. Here, we investigated whether five island populations of Aegean wall lizards (Podarcis erhardii) have more effective camouflage against their own (local) island substrates than against other (non-local) island substrates to avian predators, and whether this was linked to island differences in substrate appearance. We also investigated whether degree of local substrate matching varied among island populations and between sexes. In most populations, both sexes were better matched against local backgrounds than against non-local backgrounds, particularly in terms of luminance (perceived lightness), which usually occurred when local and non-local backgrounds were different in appearance. This was found even between island populations that historically had a land connection and in populations that have been isolated relatively recently, suggesting that isolation in these distinct island environments has been sufficient to cause enhanced local background matching, sometimes on a rapid evolutionary time-scale. However, heightened local matching was poorer in populations inhabiting more variable and unstable environments with a prolonged history of volcanic activity. Overall, these results show that lizard coloration is tuned to provide camouflage in local environments, either due to genetic adaptation or changes during development. Yet, the occurrence and extent of selection for local matching may depend on specific conditions associated with local ecology and biogeographic history. These results emphasize how anti-predator adaptations to different environments can drive divergence within a species, which may contribute to reproductive isolation among populations and lead to ecological speciation.This work was supported by a Biotechnology and Biological Sciences Research Council studentship (www.BBSRC.com), the British Herpetological Society (www.thebhs.org), the Cambridge Philosophical Society (http://www.cambridgephilosophicalsociety.org) and Magdalene College, Cambridge (to KLAM), and a Biotechnology and Biological Sciences Research Council and David Philips Research Fellowship (grant number BB/G022887/1) to MS. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript
Faecal sludge management and technology justice: promoting sustained and scalable solutions
In this paper we use Practical Action’s framework of Technology Justice and apply it to faecal sludge management. The framework analyses FSM from the perspectives of access, use and innovation. It encourages a wider systems-based approach to the issue. We illustrate the ideas by discussing how we are trying to create long-lasting change through a positive enabling environment in Bangladesh which encompasses empowerment of informal pit emptiers, engagement with Municipalities, and work to establish a new set of national guidelines
Changes in the tropical lapse rate due to entrainment and their impact on climate sensitivity
The tropical temperature in the free troposphere deviates from a theoretical moist-adiabat. The overall deviations are attributed to the entrainment of dry surrounding air. The deviations gradually approach zero in the upper troposphere, which we explain with a buoyancy-sorting mechanism: the height to which individual convective parcels rise depends on parcel buoyancy, which is closely tied to the impact of entrainment during ascent. In higher altitudes, the temperature is increasingly controlled by the convective parcels that are warmer and more buoyant because of weaker entrainment effects. We represent such temperature deviations from moist-adiabats in a clear-sky one-dimensional radiative-convective equilibrium model. Compared with a moist-adiabatic adjustment, having the entrainment-induced temperature deviations lead to higher clear-sky climate sensitivity. As the impact of entrainment depends on the saturation deficit, which increases with warming, our model predicts even more amplified surface warming from entrainment in a warmer climate. © 2021. The Authors
Modified MDRD equations outperform the original equations in Chinese patients with chronic kidney disease
Viabilidad para la construcción de un hotel campestre en el municipio de Carmen de Apicalá enfocado en el mercado de colegios, empresa pymes y turismo en general
94 páginas : ilustraciones, mapas, planos, gráficos.In order to improve the work environment, organizations have seen the need to create a prevention plan through training, business meetings, etc; thus creating the need to have a place that gives them a space to rest, relax and enjoy nature; This is how the business idea of implementing a country hotel with these characteristics arises.
likewise, it happens in educational institutions who schedule trips for their students with the intention of changing their routine and interacting in pleasant spaces.
Taking into account the new trend of alternative tourism, and the rapid growth and reception that ecotourism has had, led to study the feasibility of implementing the Hotel Campestre Bello Horizonte, in the municipality of Carmen de Apicala, near Bogota where the target market and its warm climate, is an excellent project that will benefit the business sector, since they can develop there dynamic and spaces for recreation, integration, communication. In a similar way it will benefit the schools with programmed passages and tourists in general who prefer to follow the new trend, "green tourism"En miras de mejorar el ambiente laboral las organizaciones se han visto en la necesidad de crear un plan de prevención por medio de capacitaciones, encuentros empresariales, etc.; creándose asà la necesidad de disponer de un lugar que les brinde un espacio para descansar, relajarse y disfrutar. de la naturaleza; es asà como surge la idea de negocio de implementar un hotel campestre, con estas caracterÃsticas.
Igualmente, se da en las instituciones educativas quienes programan pasadÃas para sus estudiantes con el ánimo de cambiarles la rutina e interactúen en espacios agradables.
Teniendo en cuenta la nueva tendencia del turismo alternativo, y el rápido crecimiento y acogida que ha tenido el ecoturismo, llevo a estudiar la viabilidad de-implementar el Hotel Campestre Bello Horizonte, en el municipio de Carmen. de Apicalá, cercano a Bogotá donde se encuentra el mercado meta y por su cálido clima, es un excelente proyecto que beneficiara al sector empresarial, puesto que podrán desarrollar allà dinámicas y espacios de recreación, integración, comunicación. De manera similar beneficiara a los colegios con pasadÃas programadas y turistas en general que prefieran seguir la nueva tendencia, "el turismo verde"Especialista en GerenciaEspecializació
Fabrication of calcium phosphate microcapsules using emulsion droplets stabilized with branched copolymers as templates
We report on a versatile and time-efficient method to fabricate calcium phosphate (CaP) microcapsules by utilizing oil-in-water emulsion droplets stabilized with synthetic branched copolymer (BCP) as templates. The BCP was designed to provide a suitable architecture and functionality to produce stable emulsion droplets, and to permit the mineralization of CaP at the surface of the oil droplet when incubated in a solution containing calcium and phosphate ions. The CaP shells of the microcapsules were established to be calcium deficient hydroxyapatite with incorporated chlorine and carbonate species. These capsule walls were made fluorescent by decoration with a fluorescein-bisphosphonate conjugate
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