H C J Godfray

Publications of H C J Godfray

• Effects of bacterial secondary symbionts on host plant use in pea aphids.

  Authors: A H C McLean, M van Asch, J Ferrari, H C J Godfray

  Proceedings. Biological sciences / The Royal Society. 03/2011; 278(1706):760-6.

  Aphids possess several facultative bacterial symbionts that have important effects on their hosts' biology. These have been most closely studied in the pea aphid (Acyrthosiphon pisum), a species thatAphids possess several facultative bacterial symbionts that have important effects on their hosts' biology. These have been most closely studied in the pea aphid (Acyrthosiphon pisum), a species that feeds on multiple host plants. Whether secondary symbionts influence host plant utilization is unclear. We report the fitness consequences of introducing different strains of the symbiont Hamiltonella defensa into three aphid clones collected on Lathyrus pratensis that naturally lack symbionts, and of removing symbionts from 20 natural aphid-bacterial associations. Infection decreased fitness on Lathyrus but not on Vicia faba, a plant on which most pea aphids readily feed. This may explain the unusually low prevalence of symbionts in aphids collected on Lathyrus. There was no effect of presence of symbiont on performance of the aphids on the host plants of the clones from which the H. defensa strains were isolated. Removing the symbiont from natural aphid-bacterial associations led to an average approximate 20 per cent reduction in fecundity, both on the natural host plant and on V. faba, suggesting general rather than plant-species-specific effects of the symbiont. Throughout, we find significant genetic variation among aphid clones. The results provide no evidence that secondary symbionts have a major direct role in facilitating aphid utilization of particular host plant species.

• eMonocot: Biodiversity Informatics for monocot plants

  Authors: P. Wilkin, A. Barker, Ed Baker, W. J. Baker, R. Bone, B. Clark, H. C. J. Godfray, J. Kelly, I. J. Kitching, S. J. Mayo, S. Phillips, M. J. Scoble, D. A. Simpson, V. S. Smith, S. Villalba, O. Weber

  01/2011;

• BIODIVERSITY INFORMATICS FOR MONOCOTS AND MONOCOT SYSTEMATISTS

  Authors: P. Wilkin, E. Baker, A. Barker, R. Bone, W. J. Baker, B. Clark, L. Gardiner, H. C. J. Godfray, A. Haigh, J. Kelly, I. J. Kitching, S. J. Mayo, S. Phillips, M. J. Scoble, D. A. Simpson, V. S. Smith, A. Trias, S. Villalba, M. Vorontsova, O. Weber

  01/2011;

• Global food supply. Linking policy on climate and food.

  Authors: H C J Godfray, J Pretty, S M Thomas, E J Warham, J R Beddington

  Science (New York, N.Y.). 01/2011; 331(6020):1013-4.

  Agriculture and the food system need to move center stage in preparing for UN climate negotiations in December 2011.

• Nasonia: a jewel among wasps.

  Authors: H C J Godfray

  Heredity. 03/2010; 104(3):235-6.

• An insect-endosymbiont conundrum.

  Authors: H C J Godfray

  Heredity. 10/2009;

• An age-structured model to evaluate the potential of novel malaria-control interventions: a case study of fungal biopesticide sprays.

  Authors: P A Hancock, M B Thomas, H C J Godfray

  Proceedings. Biological sciences / The Royal Society. 10/2008;

  It has recently been proposed that mosquito vectors of human diseases, particularly malaria, may be controlled by spraying with fungal biopesticides that increase the rate of adult mortality. ThoughIt has recently been proposed that mosquito vectors of human diseases, particularly malaria, may be controlled by spraying with fungal biopesticides that increase the rate of adult mortality. Though fungal pathogens do not cause instantaneous mortality, they can kill mosquitoes before they are old enough to transmit disease. A model is developed (i) to explore the potential for fungal entomopathogens to reduce significantly infectious mosquito populations, (ii) to assess the relative value of the many different fungal strains that might be used, and (iii) to help guide the tactical design of vector-control programmes. The model follows the dynamics of different classes of adult mosquitoes with the risk of mortality due to the fungus being assumed to be a function of time since infection (modelled using the Weibull distribution). It is shown that substantial reductions in mosquito numbers are feasible for realistic assumptions about mosquito, fungus and malaria biology and moderate to low daily fungal infection probability. The choice of optimal fungal strain and spraying regime is shown to depend on local mosquito and malaria biology. Fungal pathogens may also influence the ability of mosquitoes to transmit malaria and such effects are shown to further reduce vectorial capacity.

• EXPERIMENTAL EVOLUTION SHOWS DROSOPHILA MELANOGASTER RESISTANCE TO A MICROSPORIDIAN PATHOGEN HAS FITNESS COSTS.

  Authors: Roshan K Vijendravarma, Alex R Kraaijeveld, H C J Godfray

  Evolution; international journal of organic evolution. 10/2008;

  Most organisms experience strong selection to develop mechanisms to resist or tolerate their pathogens or parasites. Limits to adaptation are set by correlated responses to selection, for exampleMost organisms experience strong selection to develop mechanisms to resist or tolerate their pathogens or parasites. Limits to adaptation are set by correlated responses to selection, for example reduced abilities to detect other parasites or trade-offs with other fitness components. For a few model systems it is now becoming possible to compare the evolutionary response to a broad range of natural enemies. In Drosophila, the evolutionary responses to ectoparasitic mites, parasitoids, and fungal and bacterial pathogens have previously been studied. Here replicate lines of D. melanogaster were exposed to the microsporidian parasite Tubulinosema kingi over a period of 61 weeks, with overlapping generations. Compared to controls, exposed lines had higher early-life fecundity and increased longevity when infected suggesting successful selection for resistance or tolerance. In the absence of the pathogen, exposed lines had lower fecundity when reared under harsh environmental conditions, and were poorer larval competitors than controls. They also had relatively higher densities of haemocytes, a component of the cellular immune system. Defense against this pathogen more resembles that against macroparasites than microsparasites, and this is interpreted in the light of what is known about the mechanisms of resistance to microsporidians.

• The population genetics of using homing endonuclease genes in vector and pest management.

  Authors: Anne Deredec, Austin Burt, H. C. J. Godfray

  Genetics. 08/2008; 179(4):2013-26.

  Homing endonuclease genes (HEGs) encode proteins that in the heterozygous state cause double-strand breaks in the homologous chromosome at the precise position opposite the HEG. If the double-strandHoming endonuclease genes (HEGs) encode proteins that in the heterozygous state cause double-strand breaks in the homologous chromosome at the precise position opposite the HEG. If the double-strand break is repaired using the homologous chromosome, the HEG becomes homozygous, and this represents a powerful genetic drive mechanism that might be used as a tool in managing vector or pest populations. HEGs may be used to decrease population fitness to drive down population densities (possibly causing local extinction) or, in disease vectors, to knock out a gene required for pathogen transmission. The relative advantages of HEGs that target viability or fecundity, that are active in one sex or both, and whose target is expressed before or after homing are explored. The conditions under which escape mutants arise are also analyzed. A different strategy is to place HEGs on the Y chromosome that cause one or more breaks on the X chromosome and so disrupt sex ratio. This strategy can cause severe sex-ratio biases with efficiencies that depend on the details of sperm competition and zygote mortality. This strategy is probably less susceptible to escape mutants, especially when multiple X shredders are used.

• Selection for resistance to a fungal pathogen in Drosophila melanogaster.

  Authors: A R Kraaijeveld, H C J Godfray

  Heredity. 05/2008; 100(4):400-6.

  An artificial selection experiment designed to explore the evolution of resistance to a fungal pathogen, Beauveria bassiana, in Drosophila melanogaster is reported here. The experiment was designedAn artificial selection experiment designed to explore the evolution of resistance to a fungal pathogen, Beauveria bassiana, in Drosophila melanogaster is reported here. The experiment was designed to test whether there is sufficient additive genetic variation in this trait for increased resistance to evolve, and, if so, whether there are correlated responses that might represent a cost to defence. After 15 generations of selection, flies from selected lines did not have higher overall fitness after infection compared with control lines. The response to selection for resistance against this pathogen is thus much weaker than against other species, in particular, parasitoids. There was, however, evidence for increased late-life fecundity in selected lines, which may indicate evolved tolerance of fungal infection. This increase was accompanied by reduced early-life fitness, which may reflect the well-known trade-off between early and late reproduction. In the absence of fungal infection, selected flies had lower fitness than control flies, and the possibility that this is also a trade-off with increased tolerance is explored.

• Food web structure of three guilds of natural enemies: predators, parasitoids and pathogens of aphids.

  Authors: F J F Van Veen, C B Müller, J K Pell, H C J Godfray

  The Journal of animal ecology. 02/2008; 77(1):191-200.

  1. Most communities of insect herbivores are unlikely to be structured by resource competition, but they may be structured by apparent competition mediated by shared natural enemies. 2. The potential1. Most communities of insect herbivores are unlikely to be structured by resource competition, but they may be structured by apparent competition mediated by shared natural enemies. 2. The potential of three guilds of natural enemies (parasitoids, fungal entomopathogens and predators) to influence aphid community structure through indirect interactions is assessed. Based on the biology, we predicted that the scope for apparent competition would be greatest for the predator and least for the parasitoid guilds. 3. Separate fully quantitative food webs were constructed for 3 years for the parasitoid guild, 2 years for the pathogen guild and for a single year for the predator guild. The webs were analysed using standard food web statistics designed for binary data, and using information-theory-based metrics that make use of the full quantitative data. 4. A total of 29 aphid, 24 parasitoid, five entomopathogenic fungi and 13 aphid specialist predator species were recorded in the study. Aphid density varied among years, and two species of aphid were particularly common in different years. Omitting these species, aphid diversity was similar among years. 5. The parasitoid web showed the lowest connectance while standard food web statistics suggested the pathogen and predator webs had similar levels of connectance. However, when a measure based on quantitative data was used the pathogen web was intermediate between the other two guilds. 6. There is evidence that a single aphid species had a particularly large effect on the structure of the pathogen food web. 7. The predator and pathogen webs were not compartmentalized, and the vast majority of parasitoids were connected in a single large compartment. 8. It was concluded that indirect effects are most likely to be mediated by predators, a prediction supported by the available experimental evidence.

• The web and the structure of taxonomy.

  Authors: H C J Godfray, B R Clark, I J Kitching, S J Mayo, M J Scoble

  Systematic biology. 01/2008; 56(6):943-55.

  An easily accessible taxonomic knowledge base is critically important for all biodiversity-related sciences. At present, taxonomic information is organized and regulated by a system of rules andAn easily accessible taxonomic knowledge base is critically important for all biodiversity-related sciences. At present, taxonomic information is organized and regulated by a system of rules and conventions that date back to the introduction of binomial nomenclature by Linnaeus. The taxonomy of any particular group of organisms comprises the sum information in the taxonomic literature, supported by designated type specimens in major collections. In this article, the way modern means of disseminating information will change the practice of taxonomy, in particular the Internet, is explored. Basic taxonomic information, such as specimen-level data, location of types, and name catalogues are already available, at least for some groups, on the Web. Specialist taxonomic databases, key-construction programs, and other software useful for systematists are also increasingly available. There has also been a move towards Web-publishing of taxonomic hypotheses, though as yet this is not fully permitted by the Codes of Nomenclature. A further and more radical move would be to transfer taxonomy completely to the Web. A possible model of this is discussed, as well as a pilot project, the "CATE" initiative, which seeks to explore the advantages and disadvantages of such a move. It is argued that taxonomy needs to forge better links with its user-communities to maintain its funding base, and that an important part of this is making the products of its research more accessible through the Internet.

• The form of host density-dependence and the likelihood of host-pathogen cycles in forest-insect systems.

  Authors: W-C Liu, M B Bonsall, H C J Godfray

  Theoretical population biology. 09/2007; 72(1):86-95.

  Forest-insect systems frequently show cyclic dynamics which has been of considerable interest to both experimental and theoretical ecologists. One important issue has been the manner in whichForest-insect systems frequently show cyclic dynamics which has been of considerable interest to both experimental and theoretical ecologists. One important issue has been the manner in which density-dependence acting on the host population through resource competition influences the likelihood of population cycles. Existing models make contradictory predictions. Here, we explore two models that allow different forms of density-dependence to be examined. We find that host density-dependence can influence the persistence of the host-pathogen interaction, the likelihood of population cycles and the stability of the host-pathogen interaction. In particular, over-compensatory density-dependence is likely to lead to host-pathogen cycles while under-compensatory density-dependence can promote stability. We discuss these differences with reference to the different forms of intraspecific competition and recent developments in insect population ecology.

• Linnaeus in the information age.

  Authors: H C J Godfray

  Nature. 04/2007; 446(7133):259-60.

• Fitness effects and transmission routes of a microsporidian parasite infecting Drosophila and its parasitoids.

  Authors: P H Futerman, S J Layen, M L Kotzen, C Franzen, A R Kraaijeveld, H C J Godfray

  Parasitology. 04/2006; 132(Pt 4):479-92.

  A microsporidian infection was discovered in laboratory cultures of Drosophila species. Ultrastructural examination suggested it belonged to the poorly characterized species Tubulinosema kingi, andA microsporidian infection was discovered in laboratory cultures of Drosophila species. Ultrastructural examination suggested it belonged to the poorly characterized species Tubulinosema kingi, and morphological and sequence data are presented. We explored how T. kingi affected the fitness of Drosophila melanogaster and D. subobscura, as well as the fitness of 2 of their parasitoids, Asobara tabida and Pachycrepoideus vindemiae. In Drosophila, infections caused changes in most of the traits we looked at that were associated with fitness, in particular causing a 34-55% reduction in early-life fecundity. Parasitoid fitness was affected more severely by infection than that of their hosts, with pupal mortality in particular increasing by 75-89%. We investigated the most important routes of transmission for T. kingi in a laboratory setting. Letting Drosophila larvae feed on medium contaminated with spores from infected dead flies resulted in 100% infection. Low levels of transmission (<10%) were found between larvae, and vertically between mothers and their offspring. Parasitoids developing in infected hosts all became infected, but infected adults were neither able to transmit the pathogen to their offspring nor to their offspring's Drosophila host, either directly, or via contamination of the ovipositor or other body parts. A field survey of Drosophila and their parasitoids in southern England revealed no natural infections. We discuss the potential importance of Microsporidia in parasitoid-host interactions, and for those working with Drosophila in the laboratory.

• Aphid protected from pathogen by endosymbiont.

  Authors: Claire L Scarborough, Julia Ferrari, H C J Godfray

  Science (New York, N.Y.). 01/2006; 310(5755):1781.

  Aphids are associated with several facultative bacterial endosymbionts that may influence their interactions with other organisms. We show here that one of the three most common facultative symbiontsAphids are associated with several facultative bacterial endosymbionts that may influence their interactions with other organisms. We show here that one of the three most common facultative symbionts of pea aphid (Acyrthosiphon pisum), the bacterium Regiella insecticola, has a major effect on host resistance to a fungal pathogen. Experimental establishment of the bacterium in uninfected aphid clones led to higher survival after fungal attack. The bacteria also increased the aphid's inclusive fitness, because the presence of the symbiont reduced the probability of fungal sporulation on aphid cadavers, hence lowering the rate of transmission of the disease to nearby related aphids.

• Introduction. Taxonomy for the twenty-first century.

  Authors: H C J Godfray, S Knapp

  Philosophical transactions of the Royal Society of London. Series B, Biological sciences. 05/2004; 359(1444):559-69.

• Diversity of bacteria associated with natural aphid populations.

  Authors: S Haynes, A C Darby, T J Daniell, G Webster, F J F Van Veen, H C J Godfray, J I Prosser, A E Douglas

  Applied and environmental microbiology. 01/2004; 69(12):7216-23.

  The bacterial communities of aphids were investigated by terminal restriction fragment length polymorphism and denaturing gradient gel electrophoresis analysis of 16S rRNA gene fragments generated byThe bacterial communities of aphids were investigated by terminal restriction fragment length polymorphism and denaturing gradient gel electrophoresis analysis of 16S rRNA gene fragments generated by PCR with general eubacterial primers. By both methods, the gamma-proteobacterium Buchnera was detected in laboratory cultures of six parthenogenetic lines of the pea aphid Acyrthosiphon pisum and one line of the black bean aphid Aphis fabae, and one or more of four previously described bacterial taxa were also detected in all aphid lines except one of A. pisum. These latter bacteria, collectively known as secondary symbionts or accessory bacteria, comprised three taxa of gamma-proteobacteria (R-type [PASS], T-type [PABS], and U-type [PAUS]) and a rickettsia (S-type [PAR]). Complementary analysis of aphids from natural populations of four aphid species (A. pisum [n = 74], Amphorophora rubi [n = 109], Aphis sarothamni [n = 42], and Microlophium carnosum [n = 101]) from a single geographical location revealed Buchnera and up to three taxa of accessory bacteria, but no other bacterial taxa, in each aphid. The prevalence of accessory bacterial taxa varied significantly among aphid species but not with the sampling month (between June and August 2000). These results indicate that the accessory bacterial taxa are distributed across multiple aphid species, although with variable prevalence, and that laboratory culture does not generally result in a shift in the bacterial community in aphids. Both the transmission patterns of the accessory bacteria between individual aphids and their impact on aphid fitness are suggested to influence the prevalence of accessory bacterial taxa in natural aphid populations.

• Costs of resistance in insect-parasite and insect-parasitoid interactions.

  Authors: A R Kraaijeveld, J Ferrari, H C J Godfray

  Parasitology. 02/2002; 125 Suppl:S71-82.

  Most, if not all, organisms face attack by natural enemies and will be selected to evolve some form of defence. Resistance may have costs as well as its obvious benefits. These costs may beMost, if not all, organisms face attack by natural enemies and will be selected to evolve some form of defence. Resistance may have costs as well as its obvious benefits. These costs may be associated with actual defence or with the maintenance of the defensive machinery irrespective of whether a challenge occurs. In this paper, the evidence for costs of resistance in insect-parasite and insect-parasitoid systems is reviewed, with emphasis on two host-parasitoid systems, based on Drosophila melanogaster and pea aphids as hosts. Data from true insect-parasite systems mainly concern the costs of actual defence; evidence for the costs of standing defences is mostly circumstantial. In pea aphids, the costs of standing defences have so far proved elusive. Resistance amongst clones is not correlated with life-time fecundity, whether measured on good or poor quality plants. Successful defence by a D. melanogaster larva results in a reduction in adult size and fecundity and an increased susceptibility to pupal parasitoids. Costs of standing defences are a reduction in larval competitive ability though these costs only become important when food is limited. It is concluded that costs of resistance can play a pivotal role in the evolutionary and population dynamic interactions between hosts and their parasites.

• The form of host density-dependence and the likelihood of host–pathogen cycles in forest-insect systems

  Authors: W.-C. Liu, M.B. Bonsall, H.C.J. Godfray

  Theoretical Population Biology.

  Forest-insect systems frequently show cyclic dynamics which has been of considerable interest to both experimental and theoretical ecologists. One important issue has been the manner in whichForest-insect systems frequently show cyclic dynamics which has been of considerable interest to both experimental and theoretical ecologists. One important issue has been the manner in which density-dependence acting on the host population through resource competition influences the likelihood of population cycles. Existing models make contradictory predictions. Here, we explore two models that allow different forms of density-dependence to be examined. We find that host density-dependence can influence the persistence of the host–pathogen interaction, the likelihood of population cycles and the stability of the host–pathogen interaction. In particular, over-compensatory density-dependence is likely to lead to host–pathogen cycles while under-compensatory density-dependence can promote stability. We discuss these differences with reference to the different forms of intraspecific competition and recent developments in insect population ecology.