Phenotype-environment matching in sand fleas

This is the final version of the article. Available from the publisher via the DOI in this record.Camouflage is perhaps the most widespread anti-predator strategy in nature, found in numerous animal groups. A long-standing prediction is that individuals should have camouflage tuned to the visual backgrounds where they live. However, while several studies have demonstrated phenotype-environment associations, few have directly shown that this confers an improvement in camouflage, particularly with respect to predator vision. Here, we show that an intertidal crustacean, the sand flea (Hippa testudinaria), has coloration tuned to the different substrates on which it occurs when viewed by potential avian predators. Individual sand fleas from a small, oceanic island (Ascension) matched the colour and luminance of their own beaches more closely than neighbouring beaches to a model of avian vision. Based on past work, this phenotype-environment matching is likely to be driven through ontogenetic changes rather than genetic adaptation. Our work provides some of the first direct evidence that animal coloration is tuned to provide camouflage to prospective predators against a range of visual backgrounds, in a population of animals occurring over a small geographical range.M.S., A.E.L. and J.T.: Biotechnology and Biological Sciences Research Council (BB/G022887/1). Fieldwork was funded by the Darwin Initiative (Project no. 19-026)

No evidence of fine scale thermal adaptation in green turtles

This is the final version. Available on open access from Elsevier via the DOI in this recordData availability: Data are stored in the Ascension Island Government Conservation Department database. Data are available on figshare, under embargo until publication. Beach data: https://figshare.com/s/dc16fbd027a59560ce1d; Lab data: https://figshare.com/s/24788e81a4140547b38b.Adaptation to increasing temperatures may enable species to mitigate the long-term impacts of climate change. Sea turtles have temperature dependent sex determination (TSD) and variation in the thermal reaction norm, which influences offspring sex ratio, has been suggested as a potential adaptive mechanism to rising global temperatures. Here, we investigate the sex ratio of green turtle Chelonia mydas offspring from nests on beaches with notable differences in their thermal properties, to look for evidence of localised adaptation. We compared pivotal temperatures and hatch success in both the laboratory and in situ using eggs laid on two nesting beaches (dark vs. pale sand) at Ascension Island that represent the extremes of the range of incubation temperatures experienced by this population. We found no effect of beach of origin on pivotal temperatures, hatch success, or hatchling size in the laboratory or the wild. This suggests that turtles from the same rookery are not locally adapted to different thermal conditions experienced during incubation. Under predicted climate change scenarios, this will result in reduced hatch success and an increased proportion of female offspring unless temporal or spatial range shifts occur

Fine-scale thermal adaptation in a green turtle nesting population

Journal ArticleResearch Support, Non-U.S. Gov'tCopyright © 2011 The Royal SocietyElectronic supplementary material is available at http://dx.doi.org/ 10.1098/rspb.2011.1238 or via http://rspb.royalsocietypublishing.org.The effect of climate warming on the reproductive success of ectothermic animals is currently a subject of major conservation concern. However, for many threatened species, we still know surprisingly little about the extent of naturally occurring adaptive variation in heat-tolerance. Here, we show that the thermal tolerances of green turtle (Chelonia mydas) embryos in a single, island-breeding population have diverged in response to the contrasting incubation temperatures of nesting beaches just a few kilometres apart. In natural nests and in a common-garden rearing experiment, the offspring of females nesting on a naturally hot (black sand) beach survived better and grew larger at hot incubation temperatures compared with the offspring of females nesting on a cooler (pale sand) beach nearby. These differences were owing to shallower thermal reaction norms in the hot beach population, rather than shifts in thermal optima, and could not be explained by egg-mediated maternal effects. Our results suggest that marine turtle nesting behaviour can drive adaptive differentiation at remarkably fine spatial scales, and have important implications for how we define conservation units for protection. In particular, previous studies may have underestimated the extent of adaptive structuring in marine turtle populations that may significantly affect their capacity to respond to environmental change.NERCThe Royal SocietyThe Darwin InitiativeEuropean Social FundOverseas Territories Environment Programm

The incidence and clinical burden of respiratory syncytial virus disease identified through hospital outpatient presentations in Kenyan children

There is little information that describe the burden of respiratory syncytial virus (RSV) associated disease in the tropical African outpatient setting. Methods We studied a systematic sample of children aged <5 years presenting to a rural district hospital in Kenya with acute respiratory infection (ARI) between May 2002 and April 2004. We collected clinical data and screened nasal wash samples for RSV antigen by immunofluorescence. We used a linked demographic surveillance system to estimate disease incidence. Results Among 2143 children tested, 166 (8%) were RSV positive (6% among children with upper respiratory tract infection and 12% among children with lower respiratory tract infection (LRTI). RSV was more likely in LRTI than URTI (p<0.001). 51% of RSV cases were aged 1 year or over. RSV cases represented 3.4% of hospital outpatient presentations. Relative to RSV negative cases, RSV positive cases were more likely to have crackles (RR = 1.63; 95% CI 1.34–1.97), nasal flaring (RR = 2.66; 95% CI 1.40–5.04), in-drawing (RR = 2.24; 95% CI 1.47–3.40), fast breathing for age (RR = 1.34; 95% CI 1.03–1.75) and fever (RR = 1.54; 95% CI 1.33–1.80). The estimated incidence of RSV-ARI and RSV-LRTI, per 100,000 child years, among those aged <5 years was 767 and 283, respectively. Conclusion The burden of childhood RSV-associated URTI and LRTI presenting to outpatients in this setting is considerable. The clinical features of cases associated with an RSV infection were more severe than cases without an RSV diagnosis

Energy Content of Colliding Plane Waves using Approximate Noether Symmetries

This paper is devoted to study the energy content of colliding plane waves using approximate Noether symmetries. For this purpose, we use approximate Lie symmetry method of Lagrangian for differential equations. We formulate the first-order perturbed Lagrangian for colliding plane electromagnetic and gravitational waves. It is shown that in both cases, there does not existComment: 18 pages, accepted for publication in Brazilian J Physic

Searches for Gravitational Waves from Binary Neutron Stars: A Review

A new generation of observatories is looking for gravitational waves. These waves, emitted by highly relativistic systems, will open a new window for ob- servation of the cosmos when they are detected. Among the most promising sources of gravitational waves for these observatories are compact binaries in the final min- utes before coalescence. In this article, we review in brief interferometric searches for gravitational waves emitted by neutron star binaries, including the theory, instru- mentation and methods. No detections have been made to date. However, the best direct observational limits on coalescence rates have been set, and instrumentation and analysis methods continue to be refined toward the ultimate goal of defining the new field of gravitational wave astronomy.Comment: 30 pages, 5 Figures, to appear in "Short-Period Binary Stars: Observations, Analyses, and Results", Ed.s Eugene F. Milone, Denis A. Leahy, David W. Hobil

LifeCLEF 2016: Multimedia Life Species Identification Challenges

International audienceUsing multimedia identification tools is considered as one of the most promising solutions to help bridge the taxonomic gap and build accurate knowledge of the identity, the geographic distribution and the evolution of living species. Large and structured communities of nature observers (e.g., iSpot, Xeno-canto, Tela Botanica, etc.) as well as big monitoring equipment have actually started to produce outstanding collections of multimedia records. Unfortunately, the performance of the state-of-the-art analysis techniques on such data is still not well understood and is far from reaching real world requirements. The LifeCLEF lab proposes to evaluate these challenges around 3 tasks related to multimedia information retrieval and fine-grained classification problems in 3 domains. Each task is based on large volumes of real-world data and the measured challenges are defined in collaboration with biologists and environmental stakeholders to reflect realistic usage scenarios. For each task, we report the methodology, the data sets as well as the results and the main outcom

Seasonal shifts in foraging distribution due to individual flexibility in a tropical pelagic forager, the Ascension frigatebird

This is the final version of the article. Available from Inter Research via the DOI in this record.Predators exploiting tropical pelagic waters characterised by low fluctuations in seasonal temperature and salinity may require different foraging strategies than predators that can rely on persistently productive marine features. Consistent individual differences in foraging strategies have been found in temperate seabirds, but it is unclear whether such foraging special-isation would be beneficial in unpredictable tropical pelagic waters. We examined whether foraging trip characteristics of a tropical seabird were consistent between seasons and within individuals and explored whether seasonal changes could be explained by environmental variables. Ascension frigatebird Fregata aquila trips lasted up to 18 d and covered a total travel distance of up to 7047 km, but adult frigatebirds stayed within a radius of 1150 km of Ascension Island. We found that the 50% utilisation distribution of the population expanded southwestward in the cool season due to individuals performing more and longer trips in a southerly and westerly direction during the cool compared to the hot season. Individual repeatability was low (R < 0.25) for all trip characteristics, and we were unable to explain seasonal changes in time spent at sea using oceanographic or atmospheric variables. Instead, frigatebird usage per area was almost exclusively determined by distance from the colony, and although individuals spent more time in distant portions of their foraging trips, the amount of time spent per unit area decreased exponentially with increasing distance from the colony. This study indicates that, in a relatively featureless environment, high individual consistency may not be a beneficial trait for pelagic predators.The work on Ascension Island was partly funded by a Darwin Grant (# 19026) to Ascension Island Government and the University of Exeter (A.B. and B.G.), managed on-island by N.W. and S.W. Nigel Butcher and Andrew Asque assisted with preparation of loggers and equipment, and Elizabeth Marsden kindly provided the base station to download data

Self-Organization, Layered Structure, and Aggregation Enhance Persistence of a Synthetic Biofilm Consortium

Microbial consortia constitute a majority of the earth’s biomass, but little is known about how these cooperating communities persist despite competition among community members. Theory suggests that non-random spatial structures contribute to the persistence of mixed communities; when particular structures form, they may provide associated community members with a growth advantage over unassociated members. If true, this has implications for the rise and persistence of multi-cellular organisms. However, this theory is difficult to study because we rarely observe initial instances of non-random physical structure in natural populations. Using two engineered strains of Escherichia coli that constitute a synthetic symbiotic microbial consortium, we fortuitously observed such spatial self-organization. This consortium forms a biofilm and, after several days, adopts a defined layered structure that is associated with two unexpected, measurable growth advantages. First, the consortium cannot successfully colonize a new, downstream environment until it selforganizes in the initial environment; in other words, the structure enhances the ability of the consortium to survive environmental disruptions. Second, when the layered structure forms in downstream environments the consortium accumulates significantly more biomass than it did in the initial environment; in other words, the structure enhances the global productivity of the consortium. We also observed that the layered structure only assembles in downstream environments that are colonized by aggregates from a previous, structured community. These results demonstrate roles for self-organization and aggregation in persistence of multi-cellular communities, and also illustrate a role for the techniques of synthetic biology in elucidating fundamental biological principles