The effect of diet composition on the diversity of active gut bacteria and on the growth of Spodoptera exigua (Lepidoptera: Noctuidae)

Gut microbiota plays a functional role in nutrition among several insects. However, the situation is unclear in Lepidoptera. Field studies suggest the microbiome may not be stable and is determined by diet, while in the laboratory, Lepidoptera are routinely reared on diet containing antibiotics with unknown effects on microbial communities. Furthermore, molecular approaches for the characterization of lepidopteran microbiomes rarely describe the metabolically active gut bacteria. The aim of this study was to evaluate how diet and antibiotics affect Spodoptera exigua (Hübner) growth and the diversity and activity of the gut bacteria community. We assessed how alfalfa and wheat germ-based diets affected larval growth, in the presence and absence of streptomycin. Alfalfa diet improved larval growth, pupal mass, and survival, but antibiotic was only beneficial in the wheat germ diet. We observed diet-driven changes in the gut bacterial communities. In the active community, the alfalfa colony was dominated by Enterococcus and Rhodococcus whereas in the wheat germ colony, only Enterococcus was present. In contrast, spore-forming Bacilli species were very common members of the DNA community. In both cases, streptomycin had a selective effect on the relative abundance of the taxa present. Our study highlights the importance of characterizing both the diversity and activity of the gut microbiota community. DNA-derived communities may include environmental DNA, spores, or non-viable bacteria, while RNA-derived communities are more likely to give an accurate representation of the diversity of active members that are potentially directly involved in the metabolic processes of the host.

Manipulating multi-level selection in a fungal entomopathogen reveals social conflicts and a method for improving biocontrol traits

Changes in parasite virulence are commonly expected to lead to trade-offs in other life history traits that can affect fitness. Understanding these trade-offs is particularly important if we want to manipulate the virulence of microbial biological control agents. Theoretically, selection across different spatial scales, i.e. between- and within-hosts, shapes these trade-offs. However, trade-offs are also dependent on parasite biology. Despite their applied importance the evolution of virulence in fungal parasites is poorly understood: virulence can be unstable in culture and commonly fails to increase in simple passage experiments. We hypothesized that manipulating selection intensity at different scales would reveal virulence trade-offs in a fungal pathogen of aphids, Akanthomyces muscarius. Starting with a genetically diverse stock we selected for speed of kill, parasite yield or infectivity by manipulating competition within and between hosts and between-populations of hosts over 7 rounds of infection. We characterized ancestral and evolved lineages by whole genome sequencing and by measuring virulence, growth rate, sporulation and fitness. While several lineages showed increases in virulence, we saw none of the trade-offs commonly found in obligately-killing parasites. Phenotypically similar lineages within treatments often shared multiple single-nucleotide variants, indicating strong convergent evolution. The most dramatic phenotypic changes were in timing of sporulation and spore production in vitro. We found that early sporulation led to reduced competitive fitness but could increase yield of spores on media, a trade-off characteristic of social conflict. Notably, the selection regime with strongest between-population competition and lowest genetic diversity produced the most consistent shift to early sporulation, as predicted by social evolution theory. Multi-level selection therefore revealed social interactions novel to fungi and showed that these biocontrol agents have the genomic flexibility to improve multiple traits-virulence and spore production-that are often in conflict in other parasites.

Achievement of Target Gain Larger than Unity in an Inertial Fusion Experiment

On December 5, 2022, an indirect drive fusion implosion on the National Ignition Facility (NIF) achieved a target gain G_{target} of 1.5. This is the first laboratory demonstration of exceeding "scientific breakeven" (or G_{target}>1) where 2.05 MJ of 351 nm laser light produced 3.1 MJ of total fusion yield, a result which significantly exceeds the Lawson criterion for fusion ignition as reported in a previous NIF implosion [H. Abu-Shawareb et al. (Indirect Drive ICF Collaboration), Phys. Rev. Lett. 129, 075001 (2022)PRLTAO0031-900710.1103/PhysRevLett.129.075001]. This achievement is the culmination of more than five decades of research and gives proof that laboratory fusion, based on fundamental physics principles, is possible. This Letter reports on the target, laser, design, and experimental advancements that led to this result.

Competition and co-association, but not phosphorous availability, shape the benefits of phosphate-solubilizing root bacteria for maize (Zea mays)

Predicting the conditions under which rhizobacteria benefit plant growth remains challenging. Here we tested the hypothesis that benefits from inoculation with phosphate-solubilizing rhizobacteria will depend upon two environmental conditions: phosphate availability and competition between bacteria. We used maize-associated rhizobacteria with varying phosphate solubilization ability in experiments in soil, sterilized soil and gnotobiotic microcosms under conditions of varying orthophosphate availability, while we manipulated the intensity of competition by varying the number of isolates in plant inocula. Growth promotion by microbes did not depend on phosphate availability but was affected by interactions between inoculants: the beneficial effects of one Serratia isolate were only detectable when plants were inoculated with a single strain and the beneficial effects of a competition-sensitive Rhizobium was only detectable in sterilized soil or in microcosms inoculated with single strains. Moreover, microcosm experiments suggested that facilitation of a parasitic isolate, not competitive interactions between bacteria, prevented plants from gaining benefits from a potential mutualist. Competition and facilitation affected colonization of plants in microcosms but growth promotion by Serratia was more affected by inoculation treatment than culturable densities on roots. Experimental manipulation of seed inocula can reveal whether plant growth stimulation is robust with respect to competition, as well as the ecological strategies of different rhizobacteria. From an applied perspective, phosphate solubilization may not provide the mechanism for bacterial growth promotion but may indicate mutualistic potential due to phylogenetic associations. Importantly, benefits to plants are vulnerable to interactions between rhizobacteria and may not persist in mixed inoculations.

Group Selection as a Basis for Screening Mutagenized Libraries of Public Goods (Bacillus thuringiensis Cry Toxins)

The pesticidal toxins of Bacillus thuringiensis (Bt) supply the active proteins for genetically modified insect-resistant crops. There is therefore keen interest in finding new toxins, or improving known toxins, in order to increase the mortality of various targets. The production and screening of large libraries of mutagenized toxins are among the means of identifying improved toxins. Since Cry toxins are public goods, and do not confer advantages to producers in competition, conventional directed evolution approaches cannot be used here. Instead, thousands of individual mutants have to be sequenced and assayed individually, a costly and time-consuming process. In this study, we tested a group selection-based approach that could be used to screen an uncharacterized pool of Cry toxin mutants. This involved selecting for infectivity between subpopulations of Bt clones within metapopulations of infected insects in three rounds of passage. We also tested whether additional mutagenesis from exposure to ethyl methanesulfonate could increase infectivity or supply additional Cry toxin diversity during passage. Sequencing of pools of mutants at the end of selection showed that we could effectively screen out Cry toxin variants that had reduced toxicity with our group selection approach. The addition of extra mutagenesis during passage decreased the efficiency of selection for infectivity and did not produce any additional novel toxin diversity. Toxins with loss-of-function mutations tend to dominate mutagenized libraries, and so a process for screening out these mutants without time-consuming sequencing and characterization steps could be beneficial when applied to larger libraries. IMPORTANCE Insecticidal toxins from the bacterium Bacillus thuringiensis are widely exploited in genetically modified plants. This application creates a demand for novel insecticidal toxins that can be used to better manage resistant pests or control new or recalcitrant target species. An important means of producing novel toxins is via high-throughput mutagenesis and screening of existing toxins, a lengthy and resource-intensive process. This study describes the development and testing of an efficient means of screening a test library of mutagenized insecticidal toxins. Here, we showed that it is possible to screen out loss-of-function mutations with low infectivity within a pool without the need to characterize and sequence each mutant individually. This has the potential to improve the efficiency of processes used to identify novel proteins.

Decolonizing drug-resistant E. coli with phage and probiotics: breaking the frequency-dependent dominance of residents

Widespread antibiotic resistance in commensal bacteria creates a persistent challenge for human health. Resident drug-resistant microbes can prevent clinical interventions, colonize wounds post-surgery, pass resistance traits to pathogens or move to more harmful niches following routine interventions such as catheterization. Accelerating the removal of resistant bacteria or actively decolonizing particular lineages from hosts could therefore have a number of long-term benefits. However, removing resident bacteria via competition with probiotics, for example, poses a number of ecological challenges. Resident microbes are likely to have physiological and numerical advantages and competition based on bacteriocins or other secreted antagonists is expected to give advantages to the dominant partner, via positive frequency dependence. Since a narrow range of Escherichia coli genotypes (primarily those belonging to the clonal group ST131) cause a significant proportion of multidrug-resistant infections, this group presents a promising target for decolonization with bacteriophage, as narrow-host-range viral predation could lead to selective removal of particular genotypes. In this study we tested how a combination of an ST131-specific phage and competition from the well-known probiotic E. coli Nissle strain could displace E. coli ST131 under aerobic and anaerobic growth conditions in vitro. We showed that the addition of phage was able to break the frequency-dependent advantage of a numerically dominant ST131 isolate. Moreover, the addition of competing E. coli Nissle could improve the ability of phage to suppress ST131 by two orders of magnitude. Low-cost phage resistance evolved readily in these experiments and was not inhibited by the presence of a probiotic competitor. Nevertheless, combinations of phage and probiotic produced stable long-term suppression of ST131 over multiple transfers and under both aerobic and anaerobic growth conditions. Combinations of phage and probiotic therefore have real potential for accelerating the removal of drug-resistant commensal targets.

De novo genome assembly of Akanthomyces muscarius, a biocontrol agent of insect agricultural pests

The entomopathogenic fungus Akanthomyces muscarius is commonly used in agriculture to manage insect pests. Besides its use as a commercially important biological control agent, it also presents a potential model for studying host-pathogen interactions and the evolution of virulence in a laboratory setting. Here, we describe the first high-quality genome sequence for A. muscarius. We used long- and short-read sequencing to assemble a sequence of 36.1 Mb with an N₅₀ of 4.9 Mb. Genome annotation predicted 12347 genes, with 96.6 % completeness based on the core Hypocrealen gene set. The high-quality assembly and annotation of A. muscarius presented in this study provides an essential tool for future research on this commercially important species.

Selecting for infectivity across metapopulations can increase virulence in the social microbe Bacillus thuringiensis

Passage experiments that sequentially infect hosts with parasites have long been used to manipulate virulence. However, for many invertebrate pathogens, passage has been applied naively without a full theoretical understanding of how best to select for increased virulence and this has led to very mixed results. Understanding the evolution of virulence is complex because selection on parasites occurs across multiple spatial scales with potentially different conflicts operating on parasites with different life histories. For example, in social microbes, strong selection on replication rate within hosts can lead to cheating and loss of virulence, because investment in public goods virulence reduces replication rate. In this study, we tested how varying mutation supply and selection for infectivity or pathogen yield (population size in hosts) affected the evolution of virulence against resistant hosts in the specialist insect pathogen Bacillus thuringiensis, aiming to optimize methods for strain improvement against a difficult to kill insect target. We show that selection for infectivity using competition between subpopulations in a metapopulation prevents social cheating, acts to retain key virulence plasmids, and facilitates increased virulence. Increased virulence was associated with reduced efficiency of sporulation, and possible loss of function in putative regulatory genes but not with altered expression of the primary virulence factors. Selection in a metapopulation provides a broadly applicable tool for improving the efficacy of biocontrol agents. Moreover, a structured host population can facilitate artificial selection on infectivity, while selection on life-history traits such as faster replication or larger population sizes can reduce virulence in social microbes.

E-cigarette addiction and harm perception: Does initiation flavor choice matter?

Introduction

The 21^st century was marked by a dramatic increase in adolescent e-cigarette use in the United States (US). The popularity of non-traditional flavor types, including fruit and pastry, is thought to contribute toward growing product use nationally, leading to a variety of federal and state regulations limiting the use of non-traditional flavors in the US. The relationship between flavor type and increased adolescent use suggests a possible link between flavor use and addiction and harm perception. This study assessed if the flavor type used when initiating e-cigarette use predicted addiction and harm perceptions.

Methods

The study utilized data from the multi-wave youth Population Assessment of Tobacco Health Study. It explored the impact initiating e-cigarette use with traditional versus non-traditional flavor types among cigarette users on the outcome variables: e-cigarette addiction and harm perception. Both e-cigarette addiction and harm perception were measured using self-report, Likert scale questionnaires. Descriptive statistics characterized the study variables and linear regression analyses performed to test whether flavor initiation type is associated with addiction and harm perception.

Results

The study sample consisted of 1,043 youth (weighted N = 1,873,617) aged 12 to 17 years who reported at least one instance of e-cigarette use. After adjusting for age, age of onset, sex, race and annual household income there was no statistically significant difference in addiction levels between those initiating with traditional versus non-traditional flavors (p = 0.294). Similarly, traditional versus non-traditional flavor initiation did not show a statistically significant difference in adolescent e-cigarette harm perceptions (p = 0.601).

Conclusions

Traditionally flavored e-cigarette initiation produces similar risk for addiction and harm perceptions as non-traditionally flavored initiation. These findings suggest that banning non-traditional flavors alone may be ineffective in curbing e-cigarette addiction and harm perception. Additional research is needed to better understand which e-cigarette product characteristics and behaviors may be associated with greater addiction and reduced harm perceptions.

Lawson Criterion for Ignition Exceeded in an Inertial Fusion Experiment

For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as a proof of principle of various fusion concepts. Following the Lawson criterion, an ignited plasma is one where the fusion heating power is high enough to overcome all the physical processes that cool the fusion plasma, creating a positive thermodynamic feedback loop with rapidly increasing temperature. In inertially confined fusion, ignition is a state where the fusion plasma can begin "burn propagation" into surrounding cold fuel, enabling the possibility of high energy gain. While "scientific breakeven" (i.e., unity target gain) has not yet been achieved (here target gain is 0.72, 1.37 MJ of fusion for 1.92 MJ of laser energy), this Letter reports the first controlled fusion experiment, using laser indirect drive, on the National Ignition Facility to produce capsule gain (here 5.8) and reach ignition by nine different formulations of the Lawson criterion.

Signatures of selection in core and accessory genomes indicate different ecological drivers of diversification among Bacillus cereus clades

Bacterial clades are often ecologically distinct, despite extensive horizontal gene transfer (HGT). How selection works on different parts of bacterial pan‐genomes to drive and maintain the emergence of clades is unclear. Focusing on the three largest clades in the diverse and well‐studied Bacillus cereus sensu lato group, we identified clade‐specific core genes (present in all clade members) and then used clade‐specific allelic diversity to identify genes under purifying and diversifying selection. Clade‐specific accessory genes (present in a subset of strains within a clade) were characterized as being under selection using presence/absence in specific clades. Gene ontology analyses of genes under selection revealed that different gene functions were enriched in different clades. Furthermore, some gene functions were enriched only amongst clade‐specific core or accessory genomes. Genes under purifying selection were often clade‐specific, while genes under diversifying selection showed signs of frequent HGT. These patterns are consistent with different selection pressures acting on both the core and the accessory genomes of different clades and can lead to ecological divergence in both cases. Examining variation in allelic diversity allows us to uncover genes under clade‐specific selection, allowing ready identification of strains and their ecological niche.

The association of adolescent e-cigarette harm perception to advertising exposure and marketing type

BACKGROUND

Despite controversy over their possible health consequences, manufacturers of e-cigarettes employ a variety of marketing media to increase their popularity among adolescents. This study analyzed the relationship between adolescent e-cigarette harm perception and five types of e-cigarette advertising exposures: social media, radio, billboard, newspaper, and television.

METHODS

This study used data from Wave 4.5 of the Population Assessment of Tobacco and Health Study (PATH). PATH collects demographic data and interview individuals about issues pertaining to tobacco use, health outcomes, attitudes, and behaviors. This study applied factor analysis to three individual PATH harm perception items to develop a composite harm perception score. Using linear regression, the study explored the relationship of harm perception and participant responses to their recalled viewing of five different types (i.e., newspaper, radio, billboard, television and social media) of advertisements within the past 30 days. A second analysis explored if adjusting for exposure to anti-tobacco messaging and environmental factors such as family approval mitigated the association of harm perception and advertisement types.

RESULTS

The study sample consisted of 12,570 (weighted N = 23,993,149) individuals aged 12 to 17 years old. Unadjusted past 30-day exposure to newspaper, radio, billboard, and social media advertising all correlated with a reduced harm perception, but only the associations for newspaper and social media were statistically significant (p<0.05). After adjusting for environmental support factors, exposure to warning labels, and anti-tobacco advertisements, the analysis yielded statistically significant associations between increased e-cigarette harm perception and exposure to radio, billboard, and television advertisements (p<0.05). Adjusting for covariates also reduced the association of marketing and harm perception for all forms of media.

CONCLUSION

E-cigarette advertising influences adolescent perceptions of harm in e-cigarette use, particularly for social media and newspaper advertisements. This association weakens when adjusted for covariates such as environmental support and exposure to anti-tobacco marketing. These findings provide evidence for policy makers to continue anti-tobacco marketing and incorporate environmentally supportive strategies such as holistic, family-centered educational approaches to reduce e-cigarette use among adolescents.

Passage and the evolution of virulence in invertebrate pathogens: Fundamental and applied perspectives

Understanding the ecological and genetic factors that determine the evolution of virulence has broad value for invertebrate pathology. In addition to helping us understand the fundamental biology of our study organisms this body of theory has important applications in microbial biocontrol. Experimental tests of virulence theory are often carried out in invertebrate models and yet theory rarely informs applied passage experiments that aim to increase or maintain virulence. This review summarizes recent progress in this field with a focus on work most relevant to biological control: the virulence of invertebrate pathogens that are 'obligate killers' and which require cadavers for the production of infectious propagules. We discuss recent theory and fundamental and applied experimental evolution with bacteria, fungi, baculoviruses and nematodes. While passage experiments using baculoviruses have a long history of producing isolates with increased virulence, studies with other pathogens have not been so successful. Recent passage experiments that have applied evolution of virulence frameworks based on cooperation (kin selection) have produced novel methods and promising mutants with increased killing power. Evolution of virulence theory can provide plausible explanations for the varied results of passage experiments as well as a predictive framework for improving artificial selection.

Controlling insecticide resistant clones of the aphid, Myzus persicae, using the entomopathogenic fungus Akanthomyces muscarius: fitness cost of resistance under pathogen challenge

BACKGROUND

Biological control is a cornerstone of integrated pest management and could also play a key role in managing the evolution of insecticide resistance. Ecological theory predicts that the fitness cost of insecticide resistance can be increased under exposure to invertebrate natural enemies or pathogens, and can therefore increase the value of integrating biological control into pest management. In this study of the peach potato aphid, Myzus persicae, we aimed to identify whether insecticide resistance affected fitness and vulnerability of different aphid clones to the entomopathogenic fungus Akanthomyces muscarius.

RESULTS

Insecticide resistant clones were found to be slightly less susceptible to the pathogen than susceptible clones. However, this pattern could also be explained by the influence of length of laboratory culture, which was longer in susceptible clones and was positively correlated with susceptibility to fungi. Furthermore, resistance status did not affect aphid development time or intrinsic rate of increase of aphids. Finally, in a cage trial the application of fungus did not increase the competitive fitness of insecticide resistant clone 'O'.

CONCLUSION

We found no fitness cost in reproductive rate or pathogen susceptibility associated with chemical resistance in M. persicae. In contrast, some susceptible clones, particularly those subject to decades of laboratory rearing, showed enhanced susceptibility to a fungal pathogen, but not reduced reproductive fitness, an observation consistent with down-regulation of costly immune functions in culture. Overall, fungal pathogen control is compatible with insecticides and should not increase the selection pressure for resistance of M. persicae to chemical insecticides.

Function is a better predictor of plant rhizosphere community membership than 16S phylogeny

Rhizobacterial communities are important for plant health but we still have limited understanding of how they are constructed or how they can be manipulated. High-throughput 16S rRNA sequencing provides good information on taxonomic composition but remains an unreliable proxy for phenotypes. In this study, we tested the hypothesis that experimentally observed functional traits would be better predictors of community membership than phylogenetic origin. To test this hypothesis, we sampled communities on four plant species grown in two soil types and characterized 593 bacterial isolates in terms of antibiotic susceptibility, carbon metabolism, resource use and plant growth-promoting traits. In support of our hypothesis we found that three of the four plant species had phylogenetically diverse, but functionally constrained communities. Notably, communities did not grow best on complex media mimicking their host of origin but were distinguished by variation in overall growth characteristics (copiotrophy/oligotrophy) and antibiotic susceptibility. These data, combined with variation in phylogenetic structure, suggest that different classes of traits (antagonistic competition or resource-based) are more important in different communities. This culture-based approach supports and complements the findings of a previous high-throughput 16S rRNA analysis of this experiment and provides functional insights into the patterns observed with culture-independent methods.

Managing ecosystems in a sea of uncertainty: invasive species management and assisted colonizations

Managing ecosystems in the face of complex species interactions, and the associated uncertainty, presents a considerable ecological challenge. Altering those interactions via actions such as invasive species management or conservation translocations can result in unintended consequences, supporting the need to be able to make more informed decisions in the face of this uncertainty. We demonstrate the utility of ecosystem models to reduce uncertainty and inform future ecosystem management. We use Phillip Island, Australia, as a case study to investigate the impacts of two invasive species management options and consider whether a critically endangered mammal is likely to establish a population in the presence of invasive species. Qualitative models are used to determine the effects of apex predator removal (feral cats) and invasive prey removal (rabbits, rats, and mice). We extend this approach using Ensemble Ecosystem Models to consider how suppression, rather than eradication influences the species community; and consider whether an introduction of the critically endangered eastern barred bandicoot is likely to be successful in the presence of invasive species. Our analysis revealed the potential for unintended outcomes associated with feral cat control operations, with rats and rabbits expected to increase in abundance. A strategy based on managing prey species appeared to have the most ecosystem-wide benefits, with rodent control showing more favorable responses than a rabbit control strategy. Eastern barred bandicoots were predicted to persist under all feral cat control levels (including no control). Managing ecosystems is a complex and imprecise process. However, qualitative modeling and ensemble ecosystem modeling address uncertainty and are capable of improving and optimizing management practices. Our analysis shows that the best conservation outcomes may not always be associated with the top-down control of apex predators, and land managers should think more broadly in relation to managing bottom-up processes as well. Challenges faced in continuing to conserve biodiversity mean new, bolder, conservation actions are needed. We suggest that endangered species are capable of surviving in the presence of feral cats, potentially opening the door for more conservation translocations.

Combating ecosystem collapse from the tropics to the Antarctic

Globally, collapse of ecosystems-potentially irreversible change to ecosystem structure, composition and function-imperils biodiversity, human health and well-being. We examine the current state and recent trajectories of 19 ecosystems, spanning 58° of latitude across 7.7 M km² , from Australia's coral reefs to terrestrial Antarctica. Pressures from global climate change and regional human impacts, occurring as chronic 'presses' and/or acute 'pulses', drive ecosystem collapse. Ecosystem responses to 5-17 pressures were categorised as four collapse profiles-abrupt, smooth, stepped and fluctuating. The manifestation of widespread ecosystem collapse is a stark warning of the necessity to take action. We present a three-step assessment and management framework (3As Pathway Awareness, Anticipation and Action) to aid strategic and effective mitigation to alleviate further degradation to help secure our future.

Ugandan stakeholder hopes and concerns about gene drive mosquitoes for malaria control: new directions for gene drive risk governance

Background

The African Union’s High-Level Panel on Emerging Technologies identified gene drive mosquitoes as a priority technology for malaria elimination. The first field trials are expected in 5–10 years in Uganda, Mali or Burkina Faso. In preparation, regional and international actors are developing risk governance guidelines which will delineate the framework for identifying and evaluating risks. Scientists and bioethicists have called for African stakeholder involvement in these developments, arguing the knowledge and perspectives of those people living in malaria-afflicted countries is currently missing. However, few African stakeholders have been involved to date, leaving a knowledge gap about the local social-cultural as well as ecological context in which gene drive mosquitoes will be tested and deployed. This study investigates and analyses Ugandan stakeholders’ hopes and concerns about gene drive mosquitoes for malaria control and explores the new directions needed for risk governance.

Methods

This qualitative study draws on 19 in-depth semi-structured interviews with Ugandan stakeholders in 2019. It explores their hopes for the technology and the risks they believed pertinent. Coding began at a workshop and continued through thematic analysis.

Results

Participants’ hopes and concerns for gene drive mosquitoes to address malaria fell into three themes: (1) ability of gene drive mosquitoes to prevent malaria infection; (2) impacts of gene drive testing and deployment; and, (3) governance. Stakeholder hopes fell almost exclusively into the first theme while concerns were spread across all three. The study demonstrates that local stakeholders are able and willing to contribute relevant and important knowledge to the development of risk frameworks.

Conclusions

International processes can provide high-level guidelines, but risk decision-making must be grounded in the local context if it is to be robust, meaningful and legitimate. Decisions about whether or not to release gene drive mosquitoes as part of a malaria control programme will need to consider the assessment of both the risks and the benefits of gene drive mosquitoes within a particular social, political, ecological, and technological context. Just as with risks, benefits—and importantly, the conditions that are necessary to realize them—must be identified and debated in Uganda and its neighbouring countries.

Decades of dietary data demonstrate regional food web structures in the Southern Ocean

Understanding regional-scale food web structure in the Southern Ocean is critical to informing fisheries management and assessments of climate change impacts on Southern Ocean ecosystems and ecosystem services. Historically, a large component of Southern Ocean ecosystem research has focused on Antarctic krill, which provide a short, highly efficient food chain, linking primary producers to higher trophic levels. Over the last 15 years, the presence of alternative energy pathways has been identified and hypotheses on their relative importance in different regions raised. Using the largest circumpolar dietary database ever compiled, we tested these hypotheses using an empirical circumpolar comparison of food webs across the four major regions/sectors of the Southern Ocean (defined as south of 40°S) within the austral summer period. We used network analyses and generalizations of taxonomic food web structure to confirm that while Antarctic krill are dominant as the mid-trophic level for the Atlantic and East Pacific food webs (including the Scotia Arc and Western Antarctic Peninsula), mesopelagic fish and other krill species are dominant contributors to predator diets in the Indian and West Pacific regions (East Antarctica and the Ross Sea). We also highlight how tracking data and habitat modeling for mobile top predators in the Southern Ocean show that these species integrate food webs over large regional scales. Our study provides a quantitative assessment, based on field observations, of the degree of regional differentiation in Southern Ocean food webs and the relative importance of alternative energy pathways between regions.

Divergence in environmental adaptation between terrestrial clades of the Bacillus cereus group

The Bacillus cereus group encompasses beneficial and harmful species in diverse niches and has a much debated taxonomy. Investigating whether selection has led to ecological divergence between phylogenetic clades can help understand the basis of speciation, and has implications for predicting biological safety across this group. Using three most terrestrial species in this group (B. cereus, Bacillus thuringiensis and Bacillus mycoides) we charactererized ecological specialization in terms of resource use, thermal adaptation and fitness in different environmental conditions and tested whether taxonomic species or phylogenetic clade best explained phenotypic variation. All isolates grew vigorously in protein rich media and insect cadavers, but exploitation of soil or plant derived nutrients was similarly weak for all. For B. thuringiensis and B. mycoides, clade and taxonomic species were important predictors of relative fitness in insect infections. Fully psychrotolerant isolates could outcompete B. thuringiensis in insects at low temperature, although psychrotolerance predicted growth in artificial media better than clade. In contrast to predictions, isolates in the Bacillus anthracis clade had sub-optimal growth at 37°C. The common ecological niche in these terrestrial B. cereus species is the ability to exploit protein rich resources such as cadavers. However, selection has led to different phylogenetic groups developing different strategies for accessing this resource. Thus, clades, as well as traditional taxonomic phenotypes, predict biologically important traits.

Tracking of marine predators to protect Southern Ocean ecosystems

Southern Ocean ecosystems are under pressure from resource exploitation and climate change^1,2. Mitigation requires the identification and protection of Areas of Ecological Significance (AESs), which have so far not been determined at the ocean-basin scale. Here, using assemblage-level tracking of marine predators, we identify AESs for this globally important region and assess current threats and protection levels. Integration of more than 4,000 tracks from 17 bird and mammal species reveals AESs around sub-Antarctic islands in the Atlantic and Indian Oceans and over the Antarctic continental shelf. Fishing pressure is disproportionately concentrated inside AESs, and climate change over the next century is predicted to impose pressure on these areas, particularly around the Antarctic continent. At present, 7.1% of the ocean south of 40°S is under formal protection, including 29% of the total AESs. The establishment and regular revision of networks of protection that encompass AESs are needed to provide long-term mitigation of growing pressures on Southern Ocean ecosystems.

The retrospective analysis of Antarctic tracking data project

The Retrospective Analysis of Antarctic Tracking Data (RAATD) is a Scientific Committee for Antarctic Research project led jointly by the Expert Groups on Birds and Marine Mammals and Antarctic Biodiversity Informatics, and endorsed by the Commission for the Conservation of Antarctic Marine Living Resources. RAATD consolidated tracking data for multiple species of Antarctic meso- and top-predators to identify Areas of Ecological Significance. These datasets and accompanying syntheses provide a greater understanding of fundamental ecosystem processes in the Southern Ocean, support modelling of predator distributions under future climate scenarios and create inputs that can be incorporated into decision making processes by management authorities. In this data paper, we present the compiled tracking data from research groups that have worked in the Antarctic since the 1990s. The data are publicly available through biodiversity.aq and the Ocean Biogeographic Information System. The archive includes tracking data from over 70 contributors across 12 national Antarctic programs, and includes data from 17 predator species, 4060 individual animals, and over 2.9 million observed locations.

Shifts along the parasite-mutualist continuum are opposed by fundamental trade-offs

Theory suggests that symbionts can readily evolve more parasitic or mutualistic strategies with respect to hosts. However, many symbionts have stable interactions with hosts that improve nutrient assimilation or confer protection from pathogens. We explored the potential for evolution of increased parasitism or decreased parasitism and mutualism in a natural gut symbiosis between larvae of Plutella xylostella and the microbe Enterobacter cloacae. We focused on interactions with the pathogen, Bacillus thuringiensis: selecting for parasitism in terms of facilitating pathogen infection, or increased mutualism in terms of host protection. Selection for parasitism led to symbionts increasing pathogen-induced mortality but reduced their competitive ability with pathogens and their in vitro growth rates. Symbionts did not evolve to confer protection from pathogens. However, several lineages evolved reduced parasitism, primarily in terms of moderating impacts on host growth, potentially because prudence pays dividends through increased host size. Overall, the evolution of increased parasitism was achievable but was opposed by trade-offs likely to reduce fitness. The evolution of protection may not have occurred because suppressing growth of B. thuringiensis in the gut might provide only weak protection or because evolution towards protective interactions was opposed by the loss of competitive fitness in symbionts.

Targeting antibiotic resistant bacteria with phage reduces bacterial density in an insect host

Phage therapy is attracting growing interest among clinicians as antibiotic resistance continues becoming harder to control. However, clinical trials and animal model studies on bacteriophage treatment are still scarce and results on the efficacy vary. Recent research suggests that using traditional antimicrobials in concert with phage could have desirable synergistic effects that hinder the evolution of resistance. Here, we present a novel insect gut model to study phage-antibiotic interaction in a system where antibiotic resistance initially exists in very low frequency and phage specifically targets the resistance bearing cells. We demonstrate that while phage therapy could not reduce the frequency of target bacteria in the population during positive selection by antibiotics, it alleviated the antibiotic induced blooming by lowering the overall load of resistant cells. The highly structured gut environment had pharmacokinetic effects on both phage and antibiotic dynamics compared with in vitro: antibiotics did not reduce the overall amount of bacteria, demonstrating a simple turnover of gut microbiota from non-resistant to resistant population with little cost. The results imply moderate potential for using phage as an aid to target antibiotic resistant gut infections, and question the usefulness of in vitro inferences.

Response of the Native Springtail Parisotoma insularis to Diesel Fuel-Contaminated Soils Under Field-Realistic Exposure Conditions at Subantarctic Macquarie Island

A number of sites contaminated by petroleum hydrocarbons from past fuel spills are currently undergoing remediation on subantarctic Macquarie Island (under the jurisdiction of Tasmania, Australia). To assess the environmental risks these spills pose, and to establish remediation targets and guideline values, toxicity data for a range of native biota are required. The availability of data for local biota is limited, especially for soil invertebrates, which are critical to soil health. To examine the response of naturally occurring soil invertebrate communities to fuel contamination, intact soil cores from a range of soil types were collected along an organic carbon (OC) gradient. Organic carbon was factored into the toxicity assessment due to its toxicity-modifying potential. Soil cores were spiked with Special Antarctic Blend diesel, to mimic a fresh fuel spill at the soil surface. Springtails were the most abundant taxa, with the community heavily dominated by the native species Parisotoma insularis. This species was sensitive to fuel contamination (EC20 48 mg/kg, CI 5-188), irrespective of soil organic content. This study is the first to derive critical effect concentrations (CECs) for a subantarctic springtail species and provides important data that will be incorporated into future derivation of site-specific soil quality guideline values for fuels for Macquarie Island soils and the broader subantarctic region. Integr Environ Assess Manag 2019;15:565-574. © 2019 SETAC.

Bacteria from natural populations transfer plasmids mostly towards their kin

Plasmids play a key role in microbial ecology and evolution, yet the determinants of plasmid transfer rates are poorly understood. Particularly, interactions between donor hosts and potential recipients are understudied. Here, we investigate the importance of genetic similarity between naturally co-occurring Escherichia coli isolates in plasmid transfer. We uncover extensive variability, spanning over five orders of magnitude, in the ability of isolates to donate and receive two different plasmids, R1 and RP4. Overall, transfer is strongly biased towards clone-mates, but not correlated to genetic distance when donors and recipients are not clone-mates. Transfer is limited by the presence of a functional restriction-modification system in recipients, suggesting sharing of strain-specific defence systems contributes to bias towards kin. Such restriction of transfer to kin sets the stage for longer-term coevolutionary interactions leading to mutualism between plasmids and bacterial hosts in natural communities.

HT-SuperSAGE of the gut tissue of a Vip3Aa-resistant Heliothis virescens (Lepidoptera: Noctuidae) strain provides insights into the basis of resistance

Multitoxin Bt-crops expressing insecticidal toxins with different modes of action, for example, Cry and Vip, are expected to improve resistance management in target pests. While Cry1A resistance has been relatively well characterized in some insect species, this is not the case for Vip3A, for which no mechanism of resistance has yet been identified. Here we applied HT-SuperSAGE to analyze the transcriptome of the gut tissue of tobacco budworm Heliothis virescens (F.) laboratory-selected for Vip3Aa resistance. From a total of 1 324 252 sequence reads, 5 895 126-bp tags were obtained representing 17 751 nonsingleton unique transcripts (UniTags) from genetically similar Vip3Aa-resistant (Vip-Sel) and susceptible control (Vip-Unsel) strains. Differential expression was significant (≥2.5 fold or ≤0.4; P < 0.05) for 1989 sequences (11.2% of total UniTags), where 420 represented overexpressed (OE) and 1569 underexpressed (UE) genes in Vip-Sel. BLASTN searches mapped 419 UniTags to H. virescens sequence contigs, of which, 416 (106 OE and 310 UE) were unambiguously annotated to proteins in NCBI nonredundant protein databases. Gene Ontology distributed 345 of annotated UniTags in 14 functional categories with metabolism (including serine-type hydrolases) and translation/ribosome biogenesis being the most prevalent. A UniTag homologous to a particular member of the REsponse to PAThogen (REPAT) family was found among most overexpressed, while UniTags related to the putative Vip3Aa-binding ribosomal protein S2 (RpS2) were underexpressed. qRT-PCR of a subset of UniTags validated the HT-SuperSAGE data. This study is the first providing lepidopteran gut transcriptome associated with Vip3Aa resistance and a foundation for future attempts to elucidate the resistance mechanism.

Five rules for resistance management in the antibiotic apocalypse, a road map for integrated microbial management

Resistance to new antimicrobials can become widespread within 2-3 years. Resistance problems are particularly acute for bacteria that can experience selection as both harmless commensals and pathogenic hospital-acquired infections. New drugs, although welcome, cannot tackle the antimicrobial resistance crisis alone: new drugs must be partnered with more sustainable patterns of use. However, the broader experience of resistance management in other disciplines, and the assumptions on which resistance rests, is not widely appreciated in clinical and microbiological disciplines. Improved awareness of the field of resistance management could improve clinical outcomes and help shape novel solutions. Here, the aim is to develop a pragmatic approach to developing a sustainable integrated means of using antimicrobials, based on an interdisciplinary synthesis of best practice, recent theory and recent clinical data. This synthesis emphasizes the importance of pre-emptive action and the value of reducing the supply of genetic novelty to bacteria under selection. The weight of resistance management experience also cautions against strategies that over-rely on the fitness costs of resistance or low doses. The potential (and pitfalls) of shorter courses, antibiotic combinations and antibiotic mixing or cycling are discussed in depth. Importantly, some of variability in the success of clinical trials of mixing approaches can be explained by the number and diversity of drugs in a trial, as well as whether trials encompass single wards or the wider transmission network that is a hospital. Consideration of the importance of data, and of the initially low frequency of resistance, leads to a number of additional recommendations. Overall, reduction in selection pressure, interference with the transmission of problematic genotypes and multidrug approaches (combinations, mixing or cycling) are all likely to be required for sustainability and the protection of forthcoming drugs.

Rhizobacterial Community Assembly Patterns Vary Between Crop Species

Currently our limited understanding of crop rhizosphere community assembly hinders attempts to manipulate it beneficially. Variation in root communities has been attributed to plant host effects, soil type, and plant condition, but it is hard to disentangle the relative importance of soil and host without experimental manipulation. To examine the effects of soil origin and host plant on root associated bacterial communities we experimentally manipulated four crop species in split-plot mesocosms and surveyed variation in bacterial diversity by Illumina amplicon sequencing. Overall, plant species had a greater impact than soil type on community composition. While plant species associated with different Operational Taxonomic Units (OTUs) in different soils, plants tended to recruit bacteria from similar, higher order, taxonomic groups in different soils. However, the effect of soil on root-associated communities varied between crop species: Onion had a relatively invariant bacterial community while other species (maize and pea) had a more variable community structure. Dynamic communities could result from environment specific recruitment, differential bacterial colonization or reflect broader symbiont host range; while invariant community assembly implies tighter evolutionary or ecological interactions between plants and root-associated bacteria. Irrespective of mechanism, it appears both communities and community assembly rules vary between crop species.

Aseptic Rearing and Infection with Gut Bacteria Improve the Fitness of Transgenic Diamondback Moth, Plutella xylostella

Mass insect rearing can have a range of applications, for example in biological control of pests. The competitive fitness of released insects is extremely important in a number of applications. Here, we investigated how to improve the fitness of a transgenic diamondback moth, which has shown variation in mating ability when reared in different insectaries. Specifically we tested whether infection with a gut bacteria, Enterobacter cloacae, and aseptic rearing of larvae could improve insect growth and male performance. All larvae were readily infected with E. cloacae. Under aseptic rearing, pupal weights were reduced and there was a marginal reduction in larval survival. However, aseptic rearing substantially improved the fitness of transgenic males. In addition, under aseptic rearing, inoculation with E. cloacae increased pupal weights and male fitness, increasing the proportion of transgenic progeny from 20% to 30% relative to uninfected insects. Aseptic conditions may improve the fitness of transgenic males by excluding microbial contaminants, while symbiont inoculation could further improve fitness by providing additional protection against infection, or by normalizing insect physiology. The simple innovation of incorporating antibiotic into diet, and inoculating insects with symbiotic bacteria that are resistant to that antibiotic, could provide a readily transferable tool for other insect rearing systems.

The application of self-limiting transgenic insects in managing resistance in experimental metapopulations

The mass release of transgenic insects carrying female lethal self-limiting genes can reduce pest insect populations. Substantial releases are also a novel resistance management tool, since wild type alleles conferring susceptibility to pesticides can dilute resistance alleles in target populations. However, a potential barrier is the need for large-scale area-wide releases. Here, we address whether localized releases of transgenic insects could provide an alternative means of population suppression and resistance management, without serious loss of efficacy.We used experimental mesocosms constituting insect metapopulations to explore the evolution of resistance to the Bacillus thuringiensis toxin Cry1Ac in a high-dose/refugia landscape in the insect Plutella xylostella. We ran two selection experiments, the first compared the efficacy of "everywhere" releases and negative controls to a spatially density-dependent or "whack-a-mole" strategy that concentrated release of transgenic insects in subpopulations with elevated resistance. The second experiment tested the relative efficacy of whack-a-mole and everywhere releases under spatially homogenous and heterogeneous selection pressure.The whack-a-mole releases were less effective than everywhere releases in terms of slowing the evolution of resistance, which, in the first experiment, largely prevented the evolution of resistance. In contrast to predictions, heterogeneous whack-a-mole releases were no more effective under heterogeneous selection pressure. Heterogeneous selection pressure did, however, reduce total insect population sizes.Whack-a-mole releases provided early population suppression, indistinguishable from homogeneous everywhere releases. However, insect population densities tracked the evolution of resistance in this system, as phenotypic resistance provides access to additional diet containing the toxin Cry1Ac. Thus, as resistance levels diverged between treatments, carrying capacities and population sizes increased under the whack-a-mole approach. Synthesis and applications. Spatially density-dependent releases of transgenic insects, particularly those targeting source populations at a landscape level, could suppress pest populations in the absence of blanket area-wide releases. The benefits of self-limiting transgenic insects were reduced in spatially localized releases, suggesting that they are not ideal for "spot" treatment of resistance problems. Nevertheless, spatially homogeneous or heterogeneous releases could be used to support other resistance management interventions.

Psychological Abuse among College Women in Dating Relationships

A questionnaire designed to measure psychological abuse and kindness was responded to by 90 college women involved in dating relationships. Analysis indicated that, while many relationships were low abuse/high kindness, a substantial number were characterized by high abuse/low kindness, high abuse/high kindness and low abuse/low kindness. An analysis of these different categories of dating relationships as well as explanations as to why young women should be in such negative relationships are included. The study also indicated significant differences between women's reports of feelings and behaviors. Finally, a comparison of past versus present relationships showed proportionately few significant differences in behaviors but many significant differences in feelings. The major finding, that some college women are in dating relationships characterized by psychological abuse, was explored, and comparisons to the literature on wife abuse and courtship violence were also included.

Crystal toxins and the volunteer's dilemma in bacteria

The growth and virulence of the bacteria Bacillus thuringiensis depend on the production of Cry toxins, which are used to perforate the gut of its host. Successful invasion of the host relies on producing a threshold amount of toxin, after which there is no benefit from producing more toxin. Consequently, the production of Cry toxin appears to be a different type of social problem compared with the public goods scenarios that bacteria usually encounter. We show that selection for toxin production is a volunteer's dilemma. We make specific predictions that (a) selection for toxin production depends upon an interplay between the number of bacterial cells that each host ingests and the genetic relatedness between those cells; (b) cheats that do not produce toxin gain an advantage when at low frequencies, and at high bacterial density, allowing them to be maintained in a population alongside toxin‐producing cells. More generally, our results emphasize the diversity of the social games that bacteria play.

Reproductive performance and diving behaviour share a common sea-ice concentration optimum in Adélie penguins (Pygoscelis adeliae)

The Southern Ocean is currently experiencing major environmental changes, including in sea-ice cover. Such changes strongly influence ecosystem structure and functioning and affect the survival and reproduction of predators such as seabirds. These effects are likely mediated by reduced availability of food resources. As such, seabirds are reliable eco-indicators of environmental conditions in the Antarctic region. Here, based on 9 years of sea-ice data, we found that the breeding success of Adélie penguins (Pygoscelis adeliae) reaches a peak at intermediate sea-ice cover (ca. 20%). We further examined the effects of sea-ice conditions on the foraging activity of penguins, measured at multiple scales from individual dives to foraging trips. Analysis of temporal organisation of dives, including fractal and bout analyses, revealed an increasingly consistent behaviour during years with extensive sea-ice cover. The relationship between several dive parameters and sea-ice cover in the foraging area appears to be quadratic. In years of low and high sea-ice cover, individuals adjusted their diving effort by generally diving deeper, more frequently and by resting at the surface between dives for shorter periods of time than in years with intermediate sea-ice cover. Our study therefore suggests that sea-ice cover is likely to affect the reproductive performance of Adélie penguins through its effects on foraging behaviour, as breeding success and most diving parameters share a common optimum. Some years, however, deviated from this general trend, suggesting that other factors (e.g. precipitation during the breeding season) might sometimes become preponderant over the sea-ice effects on breeding and foraging performance. Our study highlights the value of monitoring fitness parameters and individual behaviour concomitantly over the long-term to better characterize optimal environmental conditions and potential resilience of wildlife. Such an approach is crucial if we want to anticipate the effects of environmental change on Antarctic penguin populations.

Review: the energetic value of zooplankton and nekton species of the Southern Ocean

Understanding the energy flux through food webs is important for estimating the capacity of marine ecosystems to support stocks of living resources. The energy density of species involved in trophic energy transfer has been measured in a large number of small studies, scattered over a 40-year publication record. Here, we reviewed energy density records of Southern Ocean zooplankton, nekton and several benthic taxa, including previously unpublished data. Comparing measured taxa, energy densities were highest in myctophid fishes (ranging from 17.1 to 39.3 kJ g^-1 DW), intermediate in crustaceans (7.1 to 25.3 kJ g^-1 DW), squid (16.2 to 24.0 kJ g^-1 DW) and other fish families (14.8 to 29.9 kJ g^-1 DW), and lowest in jelly fish (10.8 to 18.0 kJ g^-1 DW), polychaetes (9.2 to 14.2 kJ g^-1 DW) and chaetognaths (5.0-11.7 kJ g^-1 DW). Data reveals differences in energy density within and between species related to size, age and other life cycle parameters. Important taxa in Antarctic food webs, such as copepods, squid and small euphausiids, remain under-sampled. The variability in energy density of Electrona antarctica was likely regional rather than seasonal, although for many species with limited data it remains difficult to disentangle regional and seasonal variability. Models are provided to estimate energy density more quickly using a species' physical parameters. It will become increasingly important to close knowledge gaps to improve the ability of bioenergetic and food web models to predict changes in the capacity of Antarctic ecosystems to support marine life.

Combining the high-dose/refuge strategy and self-limiting transgenic insects in resistance management-A test in experimental mesocosms

The high-dose/refuge strategy has been the primary approach for resistance management in transgenic crops engineered with Bacillus thuringiensis toxins. However, there are continuing pressures from growers to reduce the size of Bt toxin-free refugia, which typically suffer higher damage from pests. One complementary approach is to release male transgenic insects with a female-specific self-limiting gene. This technology can reduce population sizes and slow the evolution of resistance by introgressing susceptible genes through males. Theory predicts that it could be used to facilitate smaller refugia or reverse the evolution of resistance. In this study, we used experimental evolution with caged insect populations to investigate the compatibility of the self-limiting system and the high-dose/refuge strategy in mitigating the evolution of resistance in diamondback moth, Plutella xylostella. The benefits of the self-limiting system were clearer at smaller refuge size, particularly when refugia were inadequate to prevent the evolution of resistance. We found that transgenic males in caged mesocosms could suppress population size and delay resistance development with 10% refugia and 4%-15% initial resistance allele frequency. Fitness costs in hemizygous transgenic insects are particularly important for introgressing susceptible alleles into target populations. Fitness costs of the self-limiting gene in this study (P. xylostella OX4139 line L) were incompletely dominant, and reduced fecundity and male mating competitiveness. The experimental evolution approach used here illustrates some of the benefits and pitfalls of combining mass release of self-limiting insects and the high-dose/refuge strategy, but does indicate that they can be complementary.

Lineage-specific plasmid acquisition and the evolution of specialized pathogens in Bacillus thuringiensis and the Bacillus cereus group

Bacterial plasmids can vary from small selfish genetic elements to large autonomous replicons that constitute a significant proportion of total cellular DNA. By conferring novel function to the cell, plasmids may facilitate evolution but their mobility may be opposed by co-evolutionary relationships with chromosomes or encouraged via the infectious sharing of genes encoding public goods. Here, we explore these hypotheses through large-scale examination of the association between plasmids and chromosomal DNA in the phenotypically diverse Bacillus cereus group. This complex group is rich in plasmids, many of which encode essential virulence factors (Cry toxins) that are known public goods. We characterized population genomic structure, gene content and plasmid distribution to investigate the role of mobile elements in diversification. We analysed coding sequence within the core and accessory genome of 190 B. cereus group isolates, including 23 novel sequences and genes from 410 reference plasmid genomes. While cry genes were widely distributed, those with invertebrate toxicity were predominantly associated with one sequence cluster (clade 2) and phenotypically defined Bacillus thuringiensis. Cry toxin plasmids in clade 2 showed evidence of recent horizontal transfer and variable gene content, a pattern of plasmid segregation consistent with transfer during infectious cooperation. Nevertheless, comparison between clades suggests that co-evolutionary interactions may drive association between plasmids and chromosomes and limit wider transfer of key virulence traits. Proliferation of successful plasmid and chromosome combinations is a feature of specialized pathogens with characteristic niches (Bacillus anthracis, B. thuringiensis) and has occurred multiple times in the B. cereus group.

Subterranean infestation by Holotrichia parallela larvae is associated with changes in the peanut (Arachis hypogaea L.) rhizosphere microbiome

Rhizosphere microorganisms contribute to the health and development of crops and these beneficial microbes are recruited to the root-zone when plants experience biotic/abiotic stress. The subterranean pests Holotrichia parallela cause severe crop loss in peanut (Arachis hypogaea L.) fields. Hypothesizing that infestation by H. parallela larva may influence the composition of rhizosphere microbial communities, deep sequencing of V3 and V4 hypervariable regions of 16S rRNA gene was used to characterize the rhizosphere bacteria of infested and uninfested peanuts. A total of 2,673,656 reads were generated and an average of 2558 OTUs were obtained for each sample. Comparisons of rhizosphere bacterial community structure of peanuts with those infested by H. parallela larva revealed that the relative abundance of Proteobacteria and Bacteroidetes increased, while that of Actinobacteria decreased in the rhizosphere with infestation. A significant shift in bacterial communities was observed within 24 h after infestation by principal coordinate analysis. For the 332 genera identified in 24 h treatment, infestation of white grubs led to the significant changes of abundance of 67 genera. An increase in the Pseudomonas genus of infested-samples for 24 h was verified by real-time qPCR. Our results indicate H. parallela larvae infestation can quickly leads to the change of peanut rhizosphere microbiome and enrichment of specific bacterial species. But the effects were not persistent. This study provides the insight into the function of rhizosphere microbiome in the interaction between subterranean pests and crops.

An appeal for a more evidence based approach to biopesticide safety in the EU

EFSA responded to our perspective article on the safe use of the insect pathogen Bacillus thrurigiensis (Bt). In doing so they admitted that there is no direct evidence to suggest that B. thuringiensis can cause diarrhoea. They nevertheless continue to repeat the assertion that Bt cannot be distinguished from Bacillus cereus, even though nearly all Bt strains, and certainly all biopesticide strains, can be distinguished from B. cereus using multi-locus sequencing typing. EFSA also continue to repeat the unsupported and speculative hypothesis that Bt strains could be capable of causing cryptic infections in humans. This hypothesis is very much against the weight of all available safety and epidemiological data. Moreover, genotyping schemes of B. cereus group clinical infections also show that biopesticide strains have never been associated with human infections. Our position that Bt biopesticides and Bt isolates from the clade dominated by invertebrate pathogens are incapable of causing infections in humans is well supported by the international community of scientists familiar with the data on the safety of Bt after more than four decades of extensive use in agriculture and forestry.

Moving beyond presence and absence when examining changes in species distributions

Species distributions are often simplified to binary representations of the ranges where they are present and absent. It is then common to look for changes in these ranges as indicators of the effects of climate change, the expansion or control of invasive species or the impact of human land-use changes. We argue that there are inherent problems with this approach, and more emphasis should be placed on species relative abundance rather than just presence. The sampling effort required to be confident of absence is often impractical to achieve, and estimates of species range changes based on survey data are therefore inherently sensitive to sampling intensity. Species niches estimated using presence-absence or presence-only models are broader than those for abundance and may exaggerate the viability of small marginal sink populations. We demonstrate that it is possible to transform models of predicted probability of presence to expected abundance if the sampling intensity is known. Using case studies of Antarctic mosses and temperate rain forest trees, we demonstrate additional insights into biotic change that can be gained using this method. While species becoming locally extinct or colonising new areas are extreme and obviously important impacts of global environmental change, changes in abundance could still signal important changes in biological systems and be an early warning indicator of larger future changes.

In defense of Bacillus thuringiensis, the safest and most successful microbial insecticide available to humanity - a response to EFSA

The Bacillus cereus group contains vertebrate pathogens such as B. anthracis and B. cereus and the invertebrate pathogen B. thuringiensis (Bt). Microbial biopesticides based on Bt are widely recognised as being among the safest and least environmentally damaging insecticidal products available. Nevertheless, a recent food-poisoning incident prompted a European Food Safety Authority review which argued that Bt poses a health risk equivalent to B. cereus, a causative agent of diarrhoea. However, a critical examination of available data, and this latest incident, provides no solid evidence that Bt causes diarrhoea. Although relatively high levels of B. cereus-like spores can occur in foods, genotyping demonstrates that these are predominantly naturally occurring strains rather than biopesticides. Moreover, MLST genotyping of >2000 isolates show that biopesticide genotypes have never been isolated from any clinical infection. MLST data demonstrate that B. cereus group is heterogeneous and formed of distinct clades with substantial differences in biology, ecology and host association. The group posing the greatest risk (the anthracis clade) is distantly related to the clade containing all biopesticides. These recent data support the long-held view that Bt and especially the strains used in Bt biopesticides are very safe for humans.

Estimation of total genetic effects for survival time in crossbred laying hens showing cannibalism, using pedigree or genomic information

Mortality of laying hens due to cannibalism is a major problem in the egg-laying industry. Survival depends on two genetic effects: the direct genetic effect of the individual itself (DGE) and the indirect genetic effects of its group mates (IGE). For hens housed in sire-family groups, DGE and IGE cannot be estimated using pedigree information, but the combined effect of DGE and IGE is estimated in the total breeding value (TBV). Genomic information provides information on actual genetic relationships between individuals and might be a tool to improve TBV accuracy. We investigated whether genomic information of the sire increased TBV accuracy compared with pedigree information, and we estimated genetic parameters for survival time. A sire model with pedigree information (BLUP) and a sire model with genomic information (ssGBLUP) were used. We used survival time records of 7290 crossbred offspring with intact beaks from four crosses. Cross-validation was used to compare the models. Using ssGBLUP did not improve TBV accuracy compared with BLUP which is probably due to the limited number of sires available per cross (~50). Genetic parameter estimates were similar for BLUP and ssGBLUP. For both BLUP and ssGBLUP, total heritable variance (T² ), expressed as a proportion of phenotypic variance, ranged from 0.03 ± 0.04 to 0.25 ± 0.09. Further research is needed on breeding value estimation for socially affected traits measured on individuals kept in single-family groups.

On site remediation of a fuel spill and soil reuse in Antarctica

The first large-scale remediation of fuel contamination in Antarctica treated 10000L of diesel dispersed in 1700t of soil, and demonstrated the efficacy of on-site bioremediation. The project progressed through initial site assessment and natural attenuation, passive groundwater management, then active remediation and the managed reuse of soil. Monitoring natural attenuation for the first 12years showed contaminant levels in surface soil remained elevated, averaging 5000mg/kg. By contrast, in five years of active remediation (excavation and biopile treatment) contaminant levels decreased by a factor of four. Chemical indicators showed hydrocarbon loss was apportioned to both biodegradation and evaporative processes. Hydrocarbon degradation rates were assessed against biopile soil temperatures, showing a phase of rapid degradation (first 100days above soil temperature threshold of 0°C) followed by slower degradation (beyond 100days above threshold). The biopiles operated successfully within constraints typical of harsh climates and remote sites, including limitations on resources, no external energy inputs and short field seasons. Non-native microorganisms (e.g. inoculations) and other organic materials (e.g. bulking agents) are prohibited in Antarctica making this cold region more challenging for remediation than the Arctic. Biopile operations included an initial fertiliser application, biannual mechanical turning of the soil and minimal leachate recirculation. The biopiles are a practical approach to remediate large quantities of contaminated soil in the Antarctic and already 370t have been reused in a building foundation. The findings presented demonstrate that bioremediation is a viable strategy for Antarctica and other cold regions. Operators can potentially use the modelled relationship between days above 0°C (threshold temperature) and the change in degradation rates to estimate how long it would take to remediate other sites using the biopile technology with similar soil and contaminant types.