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Dive into the research topics where Tom Reader is active.

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Featured researches published by Tom Reader.


Ecological Entomology | 2003

Understanding gregariousness in a larval Lepidopteran: the roles of host plant, predation, and microclimate

Tom Reader; Dieter F. Hochuli

Abstract.  1. Many moth and butterfly larvae are gregarious early in development, but become solitary in late instars. This ontogenetic variation in behaviour is probably the result of temporal changes in the costs and benefits associated with gregariousness. This study provides observational and experimental evidence that, in one particular moth species, a series of different ecological factors influence larval behaviour at different times during development.


Proceedings of the Royal Society of London B: Biological Sciences | 2009

Environmental heterogeneity, genotype-by-environment interactions and the reliability of sexual traits as indicators of mate quality.

Andrew D. Higginson; Tom Reader

Exaggerated sexual displays are often supposed to indicate the indirect benefits females may receive from sexual reproduction with displaying males, but empirical evidence for positive relationships between the genetic quality and sexual trait quality is scant. The explanation for this might lie in the fact that mixing of reproductive individuals whose development has been influenced by genotype-by-environment interactions (GEIs) can blur the relationship between the individual male genetic quality and phenotype as perceived by females. Strong GEIs can generate an ecological crossover, where different genotypes are superior in environments that are separated either in space or time. Here, we use a stochastic simulation model to show that even a weak GEI, which does not generate an obvious ecological crossover, can neutralize or even reverse the relationship between genetic quality and sexual trait size in the presence of environmental heterogeneity during development. Our model highlights the importance of developmental selection in evolution of traits and allows us to predict the situations in which sexual displays might not be reliable indicators of genetic quality.


Genome Biology | 2007

Application of the comprehensive set of heterozygous yeast deletion mutants to elucidate the molecular basis of cellular chromium toxicity.

Sara L. Holland; Emma Lodwig; Theodora C. Sideri; Tom Reader; Ian Clarke; Konstantinos Gkargkas; David C. Hoyle; Daniela Delneri; Stephen G. Oliver; Simon V. Avery

BackgroundThe serious biological consequences of metal toxicity are well documented, but the key modes of action of most metals are unknown. To help unravel molecular mechanisms underlying the action of chromium, a metal of major toxicological importance, we grew over 6,000 heterozygous yeast mutants in competition in the presence of chromium. Microarray-based screens of these heterozygotes are truly genome-wide as they include both essential and non-essential genes.ResultsThe screening data indicated that proteasomal (protein degradation) activity is crucial for cellular chromium (Cr) resistance. Further investigations showed that Cr causes the accumulation of insoluble and toxic protein aggregates, which predominantly arise from proteins synthesised during Cr exposure. A protein-synthesis defect provoked by Cr was identified as mRNA mistranslation, which was oxygen-dependent. Moreover, Cr exhibited synergistic toxicity with a ribosome-targeting drug (paromomycin) that is known to act via mistranslation, while manipulation of translational accuracy modulated Cr toxicity.ConclusionThe datasets from the heterozygote screen represent an important public resource that may be exploited to discover the toxic mechanisms of chromium. That potential was validated here with the demonstration that mRNA mistranslation is a primary cause of cellular Cr toxicity.


British Journal of Psychology | 2008

Do humans prefer altruistic mates? Testing a link between sexual selection and altruism towards non-relatives.

Timothy Phillips; Chris Barnard; Eamonn Ferguson; Tom Reader

Humans are often seen as unusual in displaying altruistic behaviour towards non-relatives. Here we outline and test a hypothesis that human altruistic traits evolved as a result of sexual selection. We develop a psychometric scale to measure mate preference towards altruistic traits (the MPAT scale). We then seek evidence of whether mate choice on the basis of altruistic traits is present and find it in one study (N=170 couples). We also predict that a stronger female MPAT, as measured by responses to the MPAT scale, will be expressed - a result found in all three studies (Ns=380, 340, and 398). Both sets of results are consistent with the hypothesized link between human altruism towards non-relatives and sexual selection.


Environmental Microbiology | 2014

Phenotypic heterogeneity is a selected trait in natural yeast populations subject to environmental stress

Sara L. Holland; Tom Reader; Paul S. Dyer; Simon V. Avery

Populations of genetically uniform microorganisms exhibit phenotypic heterogeneity, where individual cells have varying phenotypes. Such phenotypes include fitness-determining traits. Phenotypic heterogeneity has been linked to increased population-level fitness in laboratory studies, but its adaptive significance for wild microorganisms in the natural environment is unknown. Here, we addressed this by testing heterogeneity in yeast isolates from diverse environmental sites, each polluted with a different principal contaminant, as well as from corresponding control locations. We found that cell-to-cell heterogeneity (in resistance to the appropriate principal pollutant) was prevalent in the wild yeast isolates. Moreover, isolates with the highest heterogeneity were consistently observed in the polluted environments, indicating that heterogeneity is positively related to survival in adverse conditions in the wild. This relationship with survival was stronger than for the property of mean resistance (IC50) of an isolate. Therefore, heterogeneity could be the major determinant of microbial survival in adverse conditions. Indeed, growth assays indicated that isolates with high heterogeneities had a significant competitive advantage during stress. Analysis of yeasts after cultivation for ≥ 500 generations additionally showed that high heterogeneity evolved as a heritable trait during stress. The results showed that environmental stress selects for wild microorganisms with high levels of phenotypic heterogeneity.


Journal of Insect Behavior | 2005

Inter-Order Interactions Between Flower-Visiting Insects: Foraging Bees Avoid Flowers Previously Visited by Hoverflies

Tom Reader; Ian MacLeod; Philip T. Elliott; Oliver J. Robinson; Andrea Manica

In all insects, the ability to perceive and respond to the environment is atleast partly dependent on olfaction. Our current understanding of the waysin which insects use olfactory information has developed mainly throughstudies of pheromonal communication within species (e.g., within the so-cial Hymenoptera—Van der Meer


Proceedings of the Royal Society of London. Series B, Biological Sciences | 2009

Mothers produce less aggressive sons with altered immunity when there is a threat of disease during pregnancy

Olivia Curno; Jerzy M. Behnke; Alan G. McElligott; Tom Reader; Chris Barnard

Maternal experience before and during pregnancy is known to play a key role in offspring development. However, the influence of social cues about disease in the maternal environment has not been explored. We indirectly exposed pregnant mice to infected neighbours by housing them next to non-contagious conspecifics infected with Babesia microti. We examined the effect of this indirect immunological exposure on both the females and their adult offspring. Exposed females had higher levels of serum corticosterone and increased kidney growth compared with those with uninfected neighbours. These exposed females subsequently produced offspring that as adults showed an accelerated immune response to B. microti and less aggression in social groups. We suggest that ambient information regarding disease is used adaptively to maximize offspring survival and reproductive success in a challenging environment. Our results shed light on the impact of social information and maternal effects on life histories, and have important consequences for our understanding of epidemiology and individual disease susceptibility in humans and other animals. They also lead us to question the suitability of some laboratory housing conditions during experimental procedures, which may impact negatively upon both animal welfare and the validity of animal science.


Biodiversity and Conservation | 2009

Effect of characteristics of butterfly species on the accuracy of distribution models in an arid environment.

Tim Newbold; Tom Reader; Samy Zalat; Ahmed El-Gabbas; Francis Gilbert

Species distribution models show great promise as tools for conservation ecology. However, their accuracy has been shown to vary widely among taxa. There is some evidence that this variation is partly owing to ecological differences among species, which make them more or less easy to model. Here we test the effect of five characteristics of Egyptian butterfly species on the accuracy of distribution models, the first such comparison for butterflies in an arid environment. Unlike most previous studies, we perform independent contrasts to control for species relatedness. We show that range size, both globally and locally, has a negative effect on model accuracy. The results shed light on causes of variation in distribution model accuracy among species, and hence have relevance to practitioners using species distribution models in conservation decision making.


Methods in Ecology and Evolution | 2013

Distance transform: a tool for the study of animal colour patterns

Christopher H. Taylor; Francis Gilbert; Tom Reader

Summary The information in animal colour patterns plays a key role in many ecological interactions; quantification would help us to study them, but this is problematic. Comparing patterns using human judgement is subjective and inconsistent. Traditional shape analysis is unsuitable as patterns do not usually contain conserved landmarks. Alternative statistical approaches also have weaknesses, particularly as they are generally based on summary measures that discard most or all of the spatial information in a pattern. We present a method for quantifying the similarity of a pair of patterns based on the distance transform of a binary image. The method compares the whole pattern, pixel by pixel, while being robust to small spatial variations among images. We demonstrate the utility of the distance transform method using three ecological examples. We generate a measure of mimetic accuracy between hoverflies (Diptera: Syrphidae) and wasps (Hymenoptera) based on abdominal pattern and show that this correlates strongly with the perception of a model predator (humans). We calculate similarity values within a group of mimetic butterflies and compare this with proposed pairings of Mullerian comimics. Finally, we characterise variation in clypeal badges of a paper wasp (Polistes dominula) and compare this with previous measures of variation. While our results generally support the findings of existing studies that have used simpler ad hoc methods for measuring differences between patterns, our method is able to detect more subtle variation and hence reveal previously overlooked trends.


Bioelectromagnetics | 2009

Low-intensity microwave irradiation does not substantially alter gene expression in late larval and adult Caenorhabditis elegans

Adam Dawe; Rakesh Kumar Bodhicharla; Neil S. Graham; Sean T. May; Tom Reader; Benjamin Loader; Andrew Gregory; Mays Swicord; Giorgi Bit-Babik; David I. de Pomerai

Reports that low-intensity microwave radiation induces heat-shock reporter gene expression in the nematode, Caenorhabditis elegans, have recently been reinterpreted as a subtle thermal effect caused by slight heating. This study used a microwave exposure system (1.0 GHz, 0.5 W power input; SAR 0.9-3 mW kg(-1) for 6-well plates) that minimises temperature differentials between sham and exposed conditions (< or =0.1 degrees C). Parallel measurement and simulation studies of SAR distribution within this exposure system are presented. We compared five Affymetrix gene arrays of pooled triplicate RNA populations from sham-exposed L4/adult worms against five gene arrays of pooled RNA from microwave-exposed worms (taken from the same source population in each run). No genes showed consistent expression changes across all five comparisons, and all expression changes appeared modest after normalisation (< or =40% up- or down-regulated). The number of statistically significant differences in gene expression (846) was less than the false-positive rate expected by chance (1131). We conclude that the pattern of gene expression in L4/adult C. elegans is substantially unaffected by low-intensity microwave radiation; the minor changes observed in this study could well be false positives. As a positive control, we compared RNA samples from N2 worms subjected to a mild heat-shock treatment (30 degrees C) against controls at 26 degrees C (two gene arrays per condition). As expected, heat-shock genes are strongly up-regulated at 30 degrees C, particularly an hsp-70 family member (C12C8.1) and hsp-16.2. Under these heat-shock conditions, we confirmed that an hsp-16.2::GFP transgene was strongly up-regulated, whereas two non-heat-inducible transgenes (daf-16::GFP; cyp-34A9::GFP) showed little change in expression.

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Alan G. McElligott

Queen Mary University of London

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Tim Newbold

University College London

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Chris Barnard

University of Nottingham

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Andrew Mehigan

University of Nottingham

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