bluuebunny/crossref_metadata_2025 huggingface dataset:
Resistance is costly: trade-offs between immunity, fecundity and survival in the pea aphid
Authors: Gwynn D.M , Callaghan A , Gorham J , Walters K.F.A , Fellowes M.D.E
Published: July 2005

Parasitoids are among the most important natural enemies of insects in many environments.Acyrthosiphon pisum, the pea aphid, is a common pest of the leguminous crops in temperate regions. Pea aphids are frequently attacked by a range of endoparasitic wasps, including the common aphidiine,Aphidius ervi. Immunity to parasitoid attack is thought to involve secondary symbiotic bacteria, the presence of which is associated with the death of the parasitoid egg. It has been suggested that there is a fecundity cost of resistance, as individuals carrying the secondary symbionts associated with parasitoid resistance have fewer offspring. Supporting this hypothesis, we find a positive relationship between fecundity and susceptibility to parasitoid attack. There is also a negative relationship between fecundity and off-plant survival time (which positively correlates with resistance to parasitoid attack). Taken together, these results suggest that the aphids can either invest in defence (parasitoid resistance, increased off-plant survival time) or reproduction, and speculate that this may be mediated by changes in the aphids' endosymbiont fauna. Furthermore, there is a positive relationship between aphid size and resistance, suggesting that successful resistance to parasitoid attack may involve physical, as well as physiological, defences.
An analytical model assessing the potential threat to natural habitats from insect resistance transgenes
Authors: Kelly Colleen K , Bowler Michael G , Breden Felix , Fenner Michael , Poppy Guy M
Published: July 2005

We examine the role of ecological interactions on effective gene flow from genetically manipulated plants to their wild relatives. We do so by constructing and applying to oilseed rape (OSR) an analytical model for interaction between plants with and without an insect resistance (IR) allele in natural communities, incorporating documented levels of herbivore variability. We find that with reasonable values of advantage to the IR allele, little concomitant disadvantage (physiological costs of the allele) restricts it to low proportions of the natural population for large numbers of generations. We conclude that OSR IR transgenes are unlikely to pose an immediate threat to natural communities.

Our model identifies those factors best able to regulate particular transgenes at the population level, the most effective being impaired viability of seeds in the period between production and the following growing season, although other possibilities exist. Because solutions rely on ratios, limiting values of regulating factors are testable under controlled conditions, minimizing risk of release into the environment and offering significant advancement on existing testing programmes. Our model addresses folivory but is easily modified for herbivory damaging the seed or directly affecting seed production by infested plants, or for pathogens altering seed survival in the seedbank.
Genomic medicine: genetic variation and its impact on the future of health care
Authors: Willard Huntington F , Angrist Misha , Ginsburg Geoffrey S
Published: July 2005

Advances in genome technology and other fruits of the Human Genome Project are playing a growing role in the delivery of health care. With the development of new technologies and opportunities for large-scale analysis of the genome, transcriptome, proteome and metabolome, the genome sciences are poised to have a profound impact on clinical medicine. Cancer prognostics will be among the first major test cases for a genomic medicine paradigm, given that all cancer is caused by genomic instability, and microarrays allow assessment of patients' entire expressed genomes. Analysis of breast cancer patients' expression patterns can already be highly correlated with recurrence risks. By integrating clinical data with gene expression profiles, imaging, metabolomic profiles and proteomic data, the prospect for developing truly individualized care becomes ever more real. Notwithstanding these promises, daunting challenges remain for genomic medicine. Success will require planning robust prospective trials, analysing health care economic and outcome data, assuaging insurance and privacy concerns, developing health delivery models that are commercially viable and scaling up to meet the needs of the whole population.
Mapping and identifying genes for asthma and psoriasis
Authors: Kere Juha
Published: July 2005

Susceptibility genes for complex diseases are characterized by reduced penetrance, caused by the influence of other genes, the environment or stochastic events. Recently, positional cloning efforts have yielded several candidate susceptibility genes in different complex disorders such as Crohn's disease and asthma. Within a genetic locus, however, the identification of the effector gene may pose further challenges and require functional studies. I review two examples of such challenges: the cloning of
GPR154
(
GPRA
) and
AAA1
on chromosome 7p14 at a susceptibility locus for atopy and asthma, and the study of
HLA-Cw6
,
CCHCR1
(
HCR
) and
CDSN
on chromosome 6p21 at
PSORS1
, the major susceptibility locus for psoriasis. The susceptibility locus for atopy and asthma contains two genes and only one of them is protein coding. We studied its isoform-specific expression in bronchial biopsies and in a mouse model of ovalbumin-induced inflammation of bronchial epithelia. In the
PSORS1
locus, strong linkage disequilibrium between genes has made it difficult to distinguish the effects of the three nearby genes. We engineered transgenic mice with either a
HCR
non-risk allele or the
HCR*WWCC
risk allele controlled by the cytokeratin-14 promoter. The results suggested that the overexpression of
HCR
in mouse skin was insufficient to induce a psoriasiform phenotype, but it appeared to induce allele-specific gene expression changes that were similar to those observed in psoriatic skin.
Pharmacogenetics of drug-metabolizing enzymes: implications for a safer and more effective drug therapy
Authors: Ingelman-Sundberg Magnus , Rodriguez-Antona Cristina
Published: July 2005

The majority of phase I- and phase II-dependent drug metabolism is carried out by polymorphic enzymes which can cause abolished, quantitatively or qualitatively decreased or enhanced drug metabolism. Several examples exist where subjects carrying certain alleles do not benefit from drug therapy due to ultrarapid metabolism caused by multiple genes or by induction of gene expression or, alternatively, suffer from adverse effects of the drug treatment due to the presence of defective alleles. It is likely that future predictive genotyping for such enzymes might benefit 15–25% of drug treatments, and thereby allow prevention of adverse drug reactions and causalities, and thus improve the health of a significant fraction of the patients. However, it will take time before this will be a reality within the clinic. We describe some important aspects in the field with emphasis on cytochrome P450 and discuss also polymorphic aspects of foetal expression of
CYP3A5
and
CYP3A7
.
The genetics of human drug response
Authors: Goldstein David B
Published: July 2005

The genetics of variable drug response appears to be a more tractable complex trait than common disease predisposition. This has implications for prioritizing research and for experimental design, and in particular argues for extensive use of candidate gene based approaches in pharmacogenetic association studies. Eventually, when whole genome scanning becomes feasible, it may be appropriate to consider weighting schemes that assign higher prior probabilities of variants in genes related to the mode of action of metabolism of medicines.
Population genetic approaches to neurological disease: Parkinson's disease as an example
Authors: Gandhi S , Abou-Sleiman P.M , Healy D.G , Weale M , Gilks W , Ahmadi K , Goldstein D.B , Wood N.W
Published: July 2005

Parkinson's disease (PD) is a common, progressive, incurable disabling condition. The cause is unknown but over the past few years tremendous progress in our understanding of the genetic bases of this condition has been made. To date, this has almost exclusively come from the study of relatively rare Mendelian forms of the disease and there are no currently, widely accepted common variants known to increase susceptibility.

The role that the ‘Mendelian’ genes play in common sporadic forms of PD is unknown. Moreover, most studies in PD can really be described as candidate polymorphism studies rather than true and complete assessments of the genes themselves. We provide a model of how one might tackle some of these issues using Parkinson's disease as an illustration. One of the emerging hypotheses of gene environment interaction in Parkinson's disease is based on drug metabolizing (or xenobiotic) enzymes and their interaction with putative environmental toxins. This motivated us to describe a tagging approach for an extensive but not exhaustive list of 55 drug metabolizing enzyme genes. We use these data to illustrate the power, and some of the limitations of a haplotype tagging approach. We show that haplotype tagging is extremely efficient and works well with only a modest increase in effort through different populations. The tagging approach works much less well if the minor allele frequency is below 5%. However, it will now be possible using these tags to evaluate these genes comprehensively in PD and other neurodegenerative conditions.
Recombination hotspots as a point process
Authors: De Iorio Maria , de Silva Eric , Stumpf Michael P.H
Published: July 2005

The variation of the recombination rate along chromosomal DNA is one of the important determinants of the patterns of linkage disequilibrium. A number of inferential methods have been developed which estimate the recombination rate and its variation from population genetic data. The majority of these methods are based on modelling the genealogical process underlying a sample of DNA sequences and thus explicitly include a model of the demographic process. Here we propose a different inferential procedure based on a previously introduced framework where recombination is modelled as a point process along a DNA sequence. The approach infers regions containing putative hotspots based on the inferred minimum number of recombination events; it thus depends only indirectly on the underlying population demography. A Poisson point process model with local rates is then used to infer patterns of recombination rate estimation in a fully Bayesian framework. We illustrate this new approach by applying it to several population genetic datasets, including a region with an experimentally confirmed recombination hotspot.
Will admixture mapping work to find disease genes?
Authors: Reich David , Patterson Nick
Published: July 2005

Admixture mapping is the first experimentally practical method for carrying out a whole-genome association scan, and is thus a promising method for detecting risk factors for common disease. The goal of the community should now be to aggressively test whether the method is useful in practice for localizing disease genes, by carrying out at least three high-powered studies. We also propose a stringent criteria we believe the community should adopt before declaring a statistically significant admixture association to disease.
Pharmacogenetics in drug regulation: promise, potential and pitfalls
Authors: Shah Rashmi R
Published: July 2005

Pharmacogenetic factors operate at pharmacokinetic as well as pharmacodynamic levels—the two components of the dose–response curve of a drug. Polymorphisms in drug metabolizing enzymes, transporters and/or pharmacological targets of drugs may profoundly influence the dose–response relationship between individuals. For some drugs, although retrospective data from case studies suggests that these polymorphisms are frequently associated with adverse drug reactions or failure of efficacy, the clinical utility of such data remains unproven. There is, therefore, an urgent need for prospective data to determine whether pre-treatment genotyping can improve therapy. Various regulatory guidelines already recommend exploration of the role of genetic factors when investigating a drug for its pharmacokinetics, pharmacodynamics, dose–response relationship and drug interaction potential. Arising from the global heterogeneity in the frequency of variant alleles, regulatory guidelines also require the sponsors to provide additional information, usually pharmacogenetic bridging data, to determine whether data from one ethnic population can be extrapolated to another. At present, sponsors explore pharmacogenetic influences in early clinical pharmacokinetic studies but rarely do they carry the findings forward when designing dose–response studies or pivotal studies. When appropriate, regulatory authorities include genotype-specific recommendations in the prescribing information. Sometimes, this may include the need to adjust a dose in some genotypes under specific circumstances. Detailed references to pharmacogenetics in prescribing information and pharmacogenetically based prescribing in routine therapeutics will require robust prospective data from well-designed studies. With greater integration of pharmacogenetics in drug development, regulatory authorities expect to receive more detailed genetic data. This is likely to complicate the drug evaluation process as well as result in complex prescribing information. Genotype-specific dosing regimens will have to be more precise and marketing strategies more prudent. However, not all variations in drug responses are related to pharmacogenetic polymorphisms. Drug response can be modulated by a number of non-genetic factors, especially co-medications and presence of concurrent diseases. Inappropriate prescribing frequently compounds the complexity introduced by these two important non-genetic factors. Unless prescribers adhere to the prescribing information, much of the benefits of pharmacogenetics will be squandered.

Discovering highly predictive genotype–phenotype associations during drug development and demonstrating their clinical validity and utility in well-designed prospective clinical trials will no doubt better define the role of pharmacogenetics in future clinical practice. In the meantime, prescribing should comply with the information provided while pharmacogenetic research is deservedly supported by all concerned but without unrealistic expectations.
Structure of strontium hydroxide octahydrate, Sr(OH)2·8H2O, at 20, 100 and 200 K from neutron diffraction
Authors: Ricci J. S. , Stevens R. C. , McMullan R. K. , Klooster W. T.
Published: July 2005

The crystal structure of Sr(OH)2·8H2O has been determined at 20, 100 and 200 K from neutron diffraction data. The structure consists of double layers of H2O and OH− ions separated by Sr2+ along the c axis. The Sr2+ ions are eight-coordinated by water O atoms in a square antiprism configuration. Each H2O molecule is engaged in three hydrogen bonds. The OH− ions form chains of acceptor and donor bonds along the fourfold axis with O atoms engaged in four bonds with H2O molecules, such that both non-equivalent O atoms have square-pyramidal environments of five H atoms and the overall bonding configurations of distorted octahedra.
Atomic interactions in ethylenebis(1-indenyl)zirconium dichloride as derived by experimental electron density analysis
Authors: Stash Adam I. , Tanaka Kiyoaki , Shiozawa Kazunari , Makino Hitoshi , Tsirelson Vladimir G.
Published: July 2005

A topological analysis of the experimental electron density in racemic ethylenebis(1-indenyl)zirconium dichloride, C20H16Cl2Zr, measured at 100 (1) K, has been performed. The atomic charges calculated by the numerical integration of the electron density over the zero-flux atomic basins demonstrate the charge transfer of 2.25 e from the Zr atom to the two indenyl ligands (0.19 e to each) and two Cl atoms (0.93 e to each). All the atomic interactions were quantitatively characterized in terms of the electron density and the electronic energy-density features at the bond critical points. The Zr—C2 bond paths significantly curved towards the C1—C2 bond were found; no other bond paths connecting the Zr atom and indenyl ligand were located. At the same time, the π-electrons of the C1—C2 bond are significantly involved in the metal–ligand interaction. The electron density features indicate that the indenyl coordination can be approximately described as η1 with slippage towards η2. The `ligand-opposed' charge concentrations around the Zr atom were revealed using the Laplacian of the electron density and the one-particle potential; they were linked to the orbital representations. Bonds in the indenyl ligand were characterized using the Cioslowski–Mixon bond-order indices calculated directly from the experimental electron density.
Structure refinement of a twinned pseudo-symmetric crystal of [Mn(C10H24N4)(NCO)2]+·ClO_4^-
Authors: Rae Alan David , Mossin Susanne , Sørensen Henning Osholm
Published: July 2005

The crystal studied is a 0.545 (1):0.455 twin, space group C\bar 1, Z = 16, and is a commensurate occupational and displacive modulation of a Z = 4 idealized parent structure with the space group A2/a and a

p
= a/2, b

p
= b/2, c

p
= c. A hierarchical approach to solution and refinement led sequentially to structures in the space groups A2/a, P21/n, P\bar 1 and finally C\bar 1. The major and minor components of the reflection intensities could be identified using irreducible representations of A2/a and P21/n, which in turn suggested suitable constraints and restraints for optimizing the refinement pathway. Comparative refinement was used to show the correctness of the final structure solution and how appropriately chosen constrained refinement allowed an escape from a false minima.
Electron diffraction of tilted perovskites
Authors: Woodward David I. , Reaney Ian M.
Published: July 2005

Simulations of electron diffraction patterns for each of the known perovskite tilt systems have been performed. The conditions for the appearance of superlattice reflections arising from rotations of the octahedra are modified to take into account the effects of different tilt systems for kinematical diffraction. The use of selected-area electron diffraction as a tool for perovskite structure determination is reviewed and examples are included.
New lanthanide–nitrogen bond-valence parameters
Authors: Trzesowska Agata , Kruszynski Rafal , Bartczak Tadeusz J.
Published: July 2005

The bond-valence parameters (R

ij
), which connect bond valences and bond lengths, have been computed for lanthanide–nitrogen bonds. It has been found that values of bond-valence parameters decrease with increasing lanthanide atomic number in coordination compounds, and that they are smaller than the R

ij
parameters of inorganic compounds. As expected, the lanthanide–nitrogen bond-valence parameters are larger than lanthanide–oxygen bond-valence parameters. There are no obvious dependencies between the number of N atoms in the coordination sphere and the bond-valence parameter value.
Submolecular partitioning of morphine hydrate based on its experimental charge density at 25 K
Authors: Scheins S. , Messerschmidt M. , Luger P.
Published: July 2005

The electron density distribution of morphine hydrate has been determined from high-resolution single-crystal X-ray diffraction measurements at 25 K. A topological analysis was applied and, in order to analyze the submolecular transferability based on an experimental electron density, a partitioning of the molecule into atomic regions was carried out, making use of Bader's zero-flux surfaces to yield atomic volumes and charges. The properties obtained were compared with the theoretical calculations of smaller fragment molecules, from which the complete morphine molecule can be reconstructed, and with theoretical studies of another opiate, Oripavine PEO, reported in the literature.
Structure of KNbOB2O5 – a commensurately modulated structure
Authors: Schmid Siegbert , Wagner Trixie
Published: July 2005

Members of the AMOB2O5 (A = K, Rb, Cs, Tl; M = Nb, Ta) family of compounds can be described as modulated structures with a single superspace group and very similar modulation functions. Single-crystal X-ray diffraction data (Mo Kα radiation) are used to solve and refine the structure of KNbOB2O5 in these terms for the first time. The average structure is solved and refined in the space group Pmn21. Subsequently, the atomic modulation functions are determined using JANA2000 and superspace-group symmetry Pmn21(0,0.375,0)s. The commensurately modulated structure is finally refined as a superstructure in the space group Pbn21 using SHELXS97 converging to R
1 = 0.024.
Structure determination of the 1/1 α/β mixed lactose by X-ray powder diffraction
Authors: Lefebvre Jacques , Willart Jean-François , Caron Vincent , Lefort Ronan , Affouard Frédéric , Danède Florence
Published: July 2005

The mixed form of α/β lactose was obtained by heating amorphous α-lactose at 443 K. NMR spectroscopy determined the stoichiometry of this mixed compound to be 1/1. The X-ray powder diffraction pattern was recorded at room temperature with a sensitive curved detector (CPS 120). The structure was solved by real-space methods (simulated annealing) followed by Rietveld refinements with soft constraints on bond lengths and bond angles. The H atoms of the hydroxyl groups were localized by minimization of the crystalline energy. The cell of 1/1 α/β lactose is triclinic with the space group P1 and contains two molecules (one molecule of each anomer). The crystalline cohesion is achieved by networks of O—H...O hydrogen bonds. The width of the Bragg peaks is interpreted through a microstructural approach in terms of isotropic strain effects and anisotropic size effects.
A variable-temperature study of a phase transition in barbituric acid dihydrate
Authors: Nichol Gary S. , Clegg William
Published: July 2005

The crystal structure of barbituric acid dihydrate (C4H4N2O3·2H2O) has twice been reported as orthorhombic, space group Pnma, with all atoms (except for CH2 H atoms) lying on the mirror plane [Al-Karaghouli et al. (1977). Acta Cryst. B33, 1655–1660; Jeffrey et al. (1961). Acta Cryst. 14, 881–887]. The present study has found that at low temperatures, below 200 K, the crystal structure is no longer orthorhombic but is non-merohedrally twinned monoclinic, space group P21/n. This phase is stable down to 100 K. Above 220 K the crystal structure is orthorhombic, and between 200 and 220 K the structure undergoes a phase change, with the monoclinic-to-orthorhombic phase transition itself taking place at around 216–217 K. The size of the β angle in the monoclinic structure is temperature dependent; at 100 K β is around 94° and it decreases in magnitude towards 90° as the temperature increases. Although the hydrogen-bonding motifs are the same for both crystal systems, there are significant differences in the crystal packing, in particular the out-of-plane displacement of the two water molecules and the sp
3-hybridized C atom of barbituric acid.
The role of second coordination-sphere interactions in incommensurately modulated structures, using β-K5Yb(MoO4)4 as an example
Authors: Arakcheeva Alla , Chapuis Gervais , Petricek Vâclav , Morozov Vladimir
Published: July 2005

The incommensurate palmierite-like structure of β-K5Yb(MoO4)4, potassium ytterbium tetramolydate, has been refined in the (3 + 1)-dimensional monoclinic superspace group X2/m(0ρ0)00, with X = [0 0 0 0; ½ ½ 0 0; 0 0 ½ ½; ½ ½ ½ ½] and the unit-cell parameters a = 10.4054 (16), b = 6.1157 (12), c = 19.7751 (18) Å, β = 136.625 (10)°; q = 0.6354 (30)b*. The occupations of the K and Yb atomic positions are described by crenel functions. The structure model reveals a balanced interaction between the atoms of the first and second coordination spheres. It is shown that the third coordination sphere should not be neglected in studies of modulated structures. The ordering of the K and Yb atoms appears to be the driving force for the modulation of all the other atoms.
Pathogen clumping: an explanation for non‐linear transmission of an insect virus
Authors: D'Amico Vincent , Elkinton Joseph S. , Podgwaite John D. , Buonaccorsi J. P. , Dwyer Greg
Published: July 2005

Abstract.  1. Previous work has shown that transmission of some insect pathogens is a non‐linear process. A number of hypotheses have been put forward as explanations for this phenomenon; however, none have proven wholly satisfactory. Here we test the effects on transmission of spatial distribution of an insect virus by testing whether or not experimental manipulations of pathogen clumping lead to different values of a clumping parameter. The gypsy moth nucleopolyhedrovirus (LdMNPV) was used, which is transmitted when larvae consume virus released from previously infected larvae that have died on foliage.

2. It was found that even when virus densities on foliage were equal, overall mortality was lower when virus‐killed cadavers were clumped on foliage.

3. Non‐linearity is more pronounced when cadavers are clumped than when they are placed at random on the foliage. Placement of droplets containing LdMNPV on foliage resulted in more linear transmission compared with cadavers.

4. Spatial clumping of viral inoculum thus provides part of the explanation for non‐linear transmission in this system. The ultimate explanation for non‐linear transmission is likely to involve some combination of spatial clumping and heterogeneity in behaviours such as feeding rate or the ability to avoid pathogen.
Host selection by winged colonisers within the Myzus persicae group: a contribution towards understanding host specialisation
Authors: Margaritopoulos J. T. , Tsourapas C. , Tzortzi M. , Kanavaki O. M. , Tsitsipis J. A.
Published: July 2005

Abstract.  1. Myzus persicae sensu lato demonstrates considerable genetic variation in respect to adaptation to host plants. The subspecies M. persicae nicotianae shows a preference for tobacco, while M. persicae sensu stricto (s. str.) for other herbaceous plants. Given that winged colonisers of several aphid species play an important role in selecting host plants, here their role in the host specialisation observed in M. persicae was examined in choice and no‐choice tests conducted outdoors, in performance studies, and in DC Electrical Penetration Graph (DC‐EPG) studies.

2. In outdoor choice tests, 77% of spring migrants of M. persicae nicotianae chose tobacco, whereas equal proportions of M. persicae s. str. selected tobacco and pepper. In no‐choice tests, spring migrants settled more quickly after alighting on host rather than on non host plants, and significantly more alate M. persicae s. str. (27%) than M. persicae nicotianae (2%) left tobacco after walking briefly on the leaf surface, whilst no significant differences were found on pepper. Cross‐host transfers significantly reduced the fecundity of both summer and spring migrants of the two subspecies. Finally, the results of no‐choice tests and DC‐EPG studies showed that winged aphids distinguished their host through cues located on the plant surface or in subcutaneous tissues perceived prior to the initiation of feeding.

3. This study demonstrates the important role of winged colonisers in the evolution of host specialisation in M. persicae. The multifarious divergent selection that the two host forms experience, i.e. the selection against cross‐migrants and their subsequent generations, is a crucial factor involved in the development and maintenance of host specialisation and promotes the parallel evolution of improved host‐recognition ability.
Survival and reproduction when food is scarce: implications for a lekking Hawaiian Drosophila
Authors: Jones Therésa M. , Widemo Fredrik
Published: July 2005

Abstract.  1. In insects, larval diet can have a major impact on development, survival, and reproductive success. However, resource availability at the adult phase of the life cycle is also likely to have strong effects in species where there is an extended period of sexual maturation following adult eclosion.

2. The effect of diet on the survival and reproductive success of the lekking Hawaiian fruit fly, Drosophila grimshawi, was explored. Two generations of emerging adults were exposed to one of two feeding regimes: ‘constant’ and ‘varied’ (corresponding to food ‘each day’ or ‘every other day’ respectively). The impact of resource availability on survival and reproductive success in each generation was then investigated.

3. The probability of survival to 5 weeks old was higher for individuals fed a constant diet than individuals fed a varied diet, but was comparable for males and females.

4. There was a significant maternal effect on offspring survival. Offspring whose mothers were reared on a constant feeding regime had higher survival than offspring whose mothers were reared on a varied diet.

5. There was no relationship between feeding regime and the quantity of pheromones deposited by males (a measure of male reproductive investment); however F2 sons were more likely to deposit pheromones and deposited a larger quantity of pheromone than their F1 sires. The number and sex ratio of offspring (a measure of female reproductive effort) emerging from the F1 generation was unrelated to maternal or paternal feeding regime.

6. The implications of variation in the foraging environment for mate choice in D. grimshawi are discussed.
Influence of egg size differences within egg clutches on larval parameters in nine libellulid species (Odonata)
Authors: Schenk Kamilla , Söndgerath Dagmar
Published: July 2005

Abstract. 1. In libellulids, egg size differs between species and populations. There are also size differences within egg clutches of individual females.

2. Past experiments suggest that there are two different types of egg clutches in libellulids. Egg size decreases significantly during oviposition in species that perform non‐contact guarding during oviposition. In contrast, in species ovipositing in tandem, egg size is randomly distributed.

3. This study deals with the possible consequences of egg size variation within the different egg clutch types. The study examined whether there is a correlation between egg development time, offspring sex or larval size and egg size.

4. The current experiments were conducted in Namibia and Germany. Five non‐contact guarding and four tandem guarding libellulid species were used.

5. In some species larger eggs needed more time to develop, in some species no correlation between egg size and egg development time could be found, whereas in other species larger eggs developed faster.

6. The sex ratio was biased towards females inLeucorrhinia dubiaand inSympetrum striolatumand egg size was not associated with gender.

7. In both egg clutch types larger eggs resulted in larger larvae. In this study, evidence was found that the effects of egg size diminished with progressing larval development under good conditions. However, it is possible that the effects may have a greater influence under harsh circumstances.
A method for rapidly mass laser‐marking individually coded ground beetles (Coleoptera: Carabidae) in the field
Authors: Griffiths Georgianne J. K. , Alexander Colin J. , Birt Andrew , Holland John M. , Kennedy Peter J. , Perry Joe N. , Preston Rick , Winder Linton
Published: July 2005

Abstract.  1. A laser‐marking technique is described that may be used to rapidly mass‐mark and individually code insects in the field. In this study, ground beetles were marked but the method is applicable to a wide range of organisms with a hard exoskeleton or shell.

2. In a field‐scale capture–recapture study conducted in winter wheat, 8266 beetles were coded. Individuals marked in the first week of the trial and recaptured 2 months later retained their codes, which were therefore considered permanent.

3. Assemblages were dominated numerically by Pterostichus cupreus, which formed more than 98% of the total captures. Of the 8046 released P. cupreus, 2269 were recaptured. As an illustration of the use of these data, the POPAN parameterisation of the Jolly–Seber model was used to estimate a whole‐field population of 17 237 individuals, equating to a density of 0.46 beetles m−2.
The effect of conspecifics on individual male movement in Roesel's bush cricket, Metrioptera roeseli
Authors: Berggren Åsa
Published: July 2005

Abstract.  1. Individual movement behaviours of male Roesel's bush crickets were compared between individuals experimentally released with or without conspecifics.

2. Differences in movement behaviour were recorded between the groups, with individuals released with conspecifics moving faster and further.

3. The study shows that behavioural interactions between individuals need to be considered in population modelling. Empirical movement data derived from lone individuals would result in a significant underestimation of both population expansion (−38.1%) and inter‐patch movement (−35.8%).
The effects of foliar pubescence and nutrient enrichment on arthropod communities ofMetrosideros polymorpha(Myrtaceae)
Authors: Gruner Daniel S. , Taylor Andrew D. , Forkner Rebecca E.
Published: July 2005

Abstract. 1. Nutrient resource availability and host‐plant foliar pubescence both influence arthropod food webs, but multifactor studies are needed to understand their interdependence and relative importance. Arthropods were sampled by clipping foliage fromMetrosideros polymorpha(Myrtaceae) trees of pubescent, glabrous, and intermediate leaf forms on fertilised and unfertilised plots.

2. Fertilisation decreased leaf mass per area (LMA) but did not change the relative mass of pubescence within leaf morphological classes.

3. Fertilisation increased densities of individuals in four taxonomic orders, densities of individuals and species of all trophic levels, and the biomass of Collembola and Homoptera. Herbivore relative diversity (ShannonH′) also increased with fertilisation, but detritivore diversity declined due to increasing dominance ofSalina celebensis(Schaeffer) (Collembola).

4. Detritivore density, driven again byS. celebensis, increased with decreasing leaf pubescence, but Heteroptera and Acari were most abundant on the intermediate pubescence class, and Psocoptera density and biomass increased with increasing pubescence. Trophic‐level species density did not change with leaf morphological class, but relative diversity of all arthropods and of detritivores increased with increasing pubescence.

5. Both resource availability and leaf pubescence affectedMetrosiderosarthropod communities. However, the pervasive positive influence of fertilisation did not translate to compositional shifts, and there were no interactions with leaf morphological class. In contrast, the effects of leaf pubescence on arthropod density, biomass, and diversity were more restricted taxonomically, and non‐parametricmanovaand redundancy analyses demonstrated significant differentiation in community composition on the pubescent morphology.
Transmission dynamics of an iridescent virus in an experimental mosquito population: the role of host density
Authors: Marina Carlos F. , Fernández‐Salas Ildefonso , Ibarra Jorge E. , Arredondo‐Jiménez Juan I. , Valle Javier , Williams Trevor
Published: July 2005

Abstract. 1. The transmission of insect pathogens cannot be adequately described by direct linear functions of host and pathogen density due to heterogeneity generated from behavioural or physiological traits, or from the spatial distribution of pathogen particles. Invertebrate iridescent viruses (IIVs) can cause patent and lethal infection or a covert sub‐lethal infection in insects.Aedes aegyptilarvae were exposed to suspensions of IIV type 6 at two densities. High larval density increased the prevalence of aggression resulting in potentially fatal wounding.

2. The overall prevalence of infection (patent + covert) was positively influenced by host density and increased with exposure time in both densities. The survival time of patently infected insects was extended by ≈ 5 days compared with non‐infected insects.

3. Maximum likelihood models based on the binomial distribution were fitted to empirical results. A model incorporating heterogeneity in host susceptibility by inclusion of a pathogen‐free refuge was a significantly better fit to data than an all‐susceptible model, indicating that transmission is non‐linear. The transmission coefficient (υ) did not differ with host density whereas the faction of the population that occupied the pathogen‐free refuge (ΠR) was significantly reduced at high host density compared with the low density treatment.

4. The transmission of free‐living infective stages of an IIV inAe. aegyptilarvae is non‐linear, probably because of density‐related changes in the frequency of aggressive encounters between hosts. This alters host susceptibility to infection and effectively reduces the proportion of hosts that occupy the pathogen‐free refuge.
Egg maturation strategy and its associated trade‐offs: a synthesis focusing on Lepidoptera
Authors: Jervis Mark A. , Boggs Carol L. , Ferns Peter N.
Published: July 2005

Abstract. 1. Insects vary considerably between and within orders, and even within the same genus, in the degree to which the female's lifetime potential egg complement is mature when she emerges as an adult.

2. The ‘ovigeny index’ (OI) – the number of eggs females have ready to lay divided by the lifetime potential fecundity – quantifies variation in the degree of early life concentration of egg production, and also variation in initial reproductive effort.

3. Here, an integrated set of hypotheses is presented, based on a conceptual model of resource allocation and acquisition, concerning trade‐offs at the interspecific level between initial investment in egg production (as measured by OI) and other life‐history traits in holometabolous insects.

4. The evidence supporting each of these hypotheses is reviewed, and particular attention is paid to the Lepidoptera, as relevant life‐history data are rapidly accumulating for this ecologically and economically important group.

5. There is evidence at the interspecific level supporting: (i) a link between OI and a trade‐off between soma and non‐soma in Trichoptera and Hymenoptera (the proportionate allocation to soma decreases with increasing OI); (ii) a negative correlation between OI and dependency on external nutrient inputs (via adult feeding) in Hymenoptera and in Lepidoptera; (iii) a negative correlation between OI and the degree of polyandry (and nuptial gift, i.e. spermatophore, use) in Lepidoptera; (iv) negative correlations between OI and resource re‐allocation capabilities (egg and thoracic musculature resorption) in Hymenoptera and in Lepidoptera; (v) a negative correlation between lifespan and OI in Trichoptera, Hymenoptera, and Lepidoptera, indicating a cost of reproduction; (vi) a link between winglessness and an OI of one in Lepidoptera; (vii) a negative correlation between OI and the degree of female mobility in winged Lepidoptera; and (viii) a negative correlation between OI and larval diet breadth (as mediated by oviposition strategy) in Lepidoptera.
Paternity analysis in the golden egg bug using AFLPs: do the males preferentially accept their true genetic offspring?
Authors: García‐González F. , Núñez Y. , Ponz F. , Roldán E. R. S. , Gomendio M.
Published: July 2005

Abstract.  1. The evolution of parental care and intraspecific parasitism involve conflicts of interest between mothers and other potential care givers who contribute to enhance offspring survival. In the golden egg bug, Phyllomorpha laciniata Villers (Heteroptera: Coreidae), females lay eggs on conspecifics and on plants. The adaptive significance of egg carrying in this species has been the subject of some controversy, which can only be resolved by determining the genetic relationship between the eggs and the adult who carries them. This study examined whether male acceptance of true genetic offspring occurs with a higher frequency than that expected from random oviposition on conspecifics.

2. Paternity analysis, using Amplified Fragment Length Polymorphism (AFLP) markers, was conducted on eggs carried by males housed with field‐mated females.

3. Out of the total number of eggs sired by males in the experimental groups, the proportion of eggs carried by males that were their true genetic offspring was 30.8%.

4. Monte Carlo methods show that the probability of a male accepting an egg that is his true genetic offspring is higher than expected if females dumped eggs on males at random.

5. These results suggest that paternal care plays an important role in the maintenance of male egg carrying in this species. In addition, the methodology developed may become useful in determining true genetic parents in other species in which neither the father nor the mother can be determined by observational methods.
Movement and dispersal patterns in the bush cricketPholidoptera griseoaptera: the role of developmental stage and sex
Authors: Diekötter Tim , Csencsics Daniela , Rothenbühler Carmen , Billeter Regula , Edwards PETER J.
Published: July 2005

Abstract. 1. To persist in a highly fragmented environment, such as the intensively used agricultural landscapes of Europe, species may need to successfully disperse between sub‐populations. This paper describes a capture – mark – resight experiment to investigate movement and dispersal patterns of the flightless bush cricket speciesPholidoptera griseoaptera.

2. Movement parameters showed little difference between juveniles and imagos as well as between males and females. Both developmental stages and sexes moved considerable distances, were cap\able of crossing habitat boundaries, and showed successful inter‐patch dispersal through the agricultural matrix.

3. The results suggest thatP. griseoapteraexhibits movement behaviours that compensate for its inability to fly. It was concluded that the good dispersal ability exhibited by animals of both sexes and developmental stage is an important factor allowingP. griseoapterato persist in fragmented agricultural landscapes.
Horizontal transmission ofWolbachiain aDrosophilacommunity
Authors: Haine Eleanor R. , Pickup Nicola J. , Cook James M.
Published: July 2005

Abstract. 1. Wolbachiabacteria are reproductive parasites of arthropods and infect an estimated 20% of all insect species worldwide. In order to understand patterns ofWolbachiainfection, it is necessary to determine how infections are gained or lost.Wolbachiatransmission is mainly vertical, but horizontal transmission between different host species can result in new infections, although its ecological context is poorly understood. Horizontal transmission is often inferred from molecular phylogenies, but could be confounded by recombination between differentWolbachiastrains.

2. This study addressed these issues by using three genes:wsp,ftsZ, andgroE, to studyWolbachiainfections in fruit‐ and fungus‐feedingDrosophilacommunities in Berkshire, U.K.

3. Identical sequences were found for all three genes inDrosophila ambiguaandDrosophila tristis.This suggests horizontal transmission ofWolbachiabetween these two previously unstudiedDrosophilaspecies, which may be the result of the two host species sharing the same food substrates or parasites.

4. Wolbachiainfections might be lost from species due to curing by naturally occurring antibiotics and the presence of these is likely to vary between larval food substrates.

5. It was investigated whetherWolbachiaincidence was lower in fungus‐feeding than in fruit‐feedingDrosophilaspecies, but no significant difference based on food substrate was found.
Host age and fitness‐related traits in a koinobiont aphid parasitoid
Authors: Colinet H. , Salin C. , Boivin G. , Hance TH.
Published: July 2005

Abstract.  1. Trade‐offs play a key role in species evolution and should be found in host–parasitoid interactions where the host quality may differ between host age categories.

2. The braconid wasp, Aphidius ervi, is a solitary endoparasitoid that allows its aphid hosts to continue to feed and grow after parasitisation. The hypotheses that host age influences their quality and that female parasitoids exploit their hosts based on that quality were tested under laboratory conditions using no‐choice tests.

3. Aphidius ervi females accepted the aphid Myzus persicae for oviposition and their progeny developed successfully in all host ages. The fitness‐related traits of parasitoids did not increase linearly with the host age in which they developed. Host quality was found to be optimal at intermediate host ages and the females preferred to parasitise these hosts. The shortest progeny development time and a more female‐biased sex ratio were observed in hosts of intermediate age.

4. This study suggests the existence of multiple interactive trade‐offs occurring during host–parasitoid interactions according to host age related quality.
Alcohol and coronary heart disease risk—is there an unknown confounder?
Authors: Poikolainen Kari , Vahtera Jussi , Virtanen Marianna , Linna Anne , Kivimäki Mika
Published: July 2005

Aims To evaluate whether confounding by several known or suspected coronary heart disease risk factors are likely to explain the lower coronary heart disease risk among light alcohol drinkers compared with never‐drinkers.

Design A population‐based cross‐sectional study.

Methods Hypertension, body mass index (BMI), diabetes, depression, sleep disturbances, smoking, physical activity, life satisfaction, psychological distress, trait anxiety, independent and dependent life events, length of working hours, job control, job strain and effort–reward imbalance were compared between never‐drinkers and light drinkers (<70 g of alcohol per week). Data on 41 099 participants (6222 men, 34 877 women) were derived from two ongoing cohort studies, the ‘10‐Town Study’ and ‘Finnish Hospital Personnel Study’, in Finland in 2000–02.

Results Of the 16 comparisons under study, seven showed significant differences between never‐drinkers and light drinkers. Five of the differences favoured never‐drinkers and two showed a disadvantage. The latter were low BMI and low leisure‐time physical activity, both more common among never‐drinkers than among light drinkers. In contrast, smoking, sleep disturbances, trait anxiety, effort–reward imbalance and dependent life events were less common among never‐drinkers than among light drinkers.

Conclusions None of the risk factors studied was a likely candidate for an unknown confounder.
Five‐year trends in patterns of drug use among people who use stimulants in dance contexts in the United Kingdom
Authors: McCambridge Jim , Mitcheson Luke , Winstock Adam , Hunt Neil
Published: July 2005

Aims  To describe and evaluate trends in the use of stimulant drugs over a 5‐year period using an under‐studied data collection method.

Design  Repeated‐measures cross‐sectional survey.

Setting and participants  Annual magazine‐based survey targeting people who use stimulant drugs in dance contexts.

Measurements  Life‐time use prevalence (ever used), age of first use, current use prevalence (any use within the last month) and extent of use within the last month (number of days used) for a range of stimulant drugs. Additional measures of quantity of ecstasy used were also collected.

Findings  Trends in life‐time and current prevalence over time have been detected and comparisons made between different stimulant drugs. Evidence is obtained of broad stability in patterns of stimulant use in respect of age of first use and frequency of use among ongoing users. Despite an apparent reduction in the current prevalence of ecstasy use, the proportion of heavy users (usually >4 pills per session) has more than doubled between 1999 and 2003.

Conclusions  This purposively sampled population study has yielded time trend data broadly consistent with other indicators, where they exist, and also has demonstrable potential to identify new drug trends. Further comparisons of purposive samples and randomly formed samples are needed.