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Identification and application of bacterial volatiles to attract a generalist aphid parasitoid: from laboratory to greenhouse assays
Get PDFThis is the peer reviewed version of the following article: [Goelen, T., Vuts, J., Sobhy, I. S., Wäckers, F., Caulfield, J. C., Birkett, M. A., Rediers, H., Jacquemyn, H., & Lievens, B. (2021). Identification and application of bacterial volatiles to attract a generalist aphid parasitoid: from laboratory to greenhouse assays. Pest Management Science, 77(2), 930–938], which has been published in final form at [https://doi.org/10.1002/ps.6102]. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited.BACKGROUND: Recent studies have shown that microorganisms emit volatile compounds that affect insect behaviour. However, it remains largely unclear whether microbes can be exploited as a source of attractants to improve biological control of insect pests. In this study, we used a combination of coupled gas chromatography-electroantennography (GC-EAG) and Y-tube olfactometer bioassays to identify attractive compounds in the volatile extracts of three bacterial strains that are associated with the habitat of the generalist aphid parasitoid Aphidius colemani, and to create mixtures of synthetic compounds to find attractive blends for A. colemani. Subsequently, the most attractive blend was evaluated in two-choice cage experiments under greenhouse conditions.
RESULTS: GC-EAG analysis revealed 20 compounds that were linked to behaviourally attractive bacterial strains. A mixture of two EAG-active compounds, styrene and benzaldehyde applied at a respective dose of 1 μg and 10 ng, was more attractive than the single compounds or the culture medium of the bacteria in Y-tube olfactometer bioassays. Application of this synthetic mixture under greenhouse conditions resulted in significant attraction of the parasitoids, and outperformed application of the bacterial culture medium.
CONCLUSION: Compounds isolated from bacterial blends were capable of attracting parasitoids both in laboratory and greenhouse assays, indicating that microbial cultures are an effective source of insect attractants. This opens new opportunities to attract and retain natural enemies of pest species and to enhance biological pest control.The authors would like to thank the Flemish Fund for Scientific Research (FWO; 1S15116316N) and Flanders Innovation & Entrepreneurship (VLAIO; HBC.2018/2022) for financial support. Further, the authors are grateful to Dries Belmans and Francine van Neerbos for help with the experiments, and Sofie Bossaert for help with the figures
Sweet scents: Nectar specialist yeasts enhance nectar attraction of a generalist aphid parasitoid without affecting survival
Get PDFCopyright © 2018 Sobhy, Baets, Goelen, Herrera-Malaver, Bosmans, Van den Ende, Verstrepen, Wäckers, Jacquemyn and Lievens.Floral nectar is commonly inhabited by microorganisms, mostly yeasts and bacteria, which can have a strong impact on nectar chemistry and scent. Yet, little is known about the effects of nectar microbes on the behavior and survival of insects belonging to the third trophic level such as parasitoids. Here, we used five nectar-inhabiting yeast species to test the hypothesis that yeast species that almost solely occur in nectar, and therefore substantially rely on floral visitors for dispersal, produce volatile compounds that enhance insect attraction without compromising insect life history parameters, such as survival. Experiments were performed using two nectar specialist yeasts (Metschnikowia gruessii and M. reukaufii) and three generalist species (Aureobasidium pullulans, Hanseniaspora uvarum, and Sporobolomyces roseus). Saccharomyces cerevisiae was included as a reference yeast. We compared olfactory responses of the generalist aphid parasitoid Aphidius ervi (Haliday) (Hymenoptera: Braconidae) when exposed to these microorganisms inoculated in synthetic nectar. Nectar-inhabiting yeasts had a significant impact on nectar chemistry and produced distinct volatile blends, some of which were attractive, while others were neutral or repellent. Among the different yeast species tested, the nectar specialists M. gruessii and M. reukaufii were the only species that produced a highly attractive nectar to parasitoid females, which simultaneously had no adverse effects on longevity and survival of adults. By contrast, parasitoids that fed on nectars fermented with the reference strain, A. pullulans, H. uvarum or S. roseus showed shortest longevity and lowest survival. Additionally, nectars fermented by A. pullulans or S. roseus were consumed significantly less, suggesting a lack of important nutrients or undesirable changes in the nectar chemical profiles. Altogether our results indicate that nectar-inhabiting yeasts play an important, but so far largely overlooked, role in plant-insect interactions by modulating the chemical composition of nectar, and may have important ecological consequences for plant pollination and biological control of herbivorous insects.This work was supported by a KU Leuven Specialization Research Grant for Researchers from the South to ISS (No. 0086389) and a KU Leuven C3 project (IOF-C32/15/020)
Oral secretions affect HIPVs induced by generalist (Mythimna loreyi) and specialist (Parnara guttata) herbivores in rice
No full textThis article is not available on ChesterRep.Plants synthesize variable mixtures of herbivore-induced plant volatiles (HIPVs) as part of their evolutionary conserved defense. To elucidate the impact of chewing herbivores with different level of adaptation on HIPV profiles in rice, we measured HIPVs released from rice seedlings challenged by either the generalist herbivore Mythimna loreyi (MYL) or the specialist Parnara guttata (PAG). Both herbivores markedly elicited the emission of HIPVs, mainly on the second and third days after attack compared to control plants. In addition, side-by-side HIPV comparisons using MYL and PAG caterpillars revealed that generalist feeding induced comparably more HIPVs relative to specialist, particularly on day two as highlighted by multivariate analysis (PLS-DA) of emitted HIPVs, and further confirmed in mimicked herbivory experiments. Here, mechanically wounded plants treated with water (WW) released more VOCs than untreated controls, and on top of this, oral secretions (OS) from both herbivores showed differential effects on volatile emissions from the wounded plants. Similar to actual herbivory, MYL OS promoted higher amounts of HIPVs relative to PAG OS, thus supporting disparate induction of rice indirect defenses in response to generalist and specialist herbivores, which could be due to the differential composition of their OS. (196 words).We thank Yuko Hojo for valuable help with insect rearing and maintenance. I. S. Sobhy was supported by the Japan Society for the Promotion of Science (JSPS) postdoctoral fellowship for foreigner researcher P13379. I. S. Sobhy gratefully acknowledges the permission of Suez Canal University, Ismailia, Egypt to undertake his postdoctoral fellowship. This work was supported in part by Grants-in-Aid for Scientific Research No. 24570026
Insect oral secretions suppress wound-induced responses in Arabidopsis
Get PDF© 2011 The Author(s).The induction of plant defences and their subsequent suppression by insects is thought to be an important factor in the evolutionary arms race between plants and herbivores. Although insect oral secretions (OS) contain elicitors that trigger plant immunity, little is known about the suppressors of plant defences. The Arabidopsis thaliana transcriptome was analysed in response to wounding and OS treatment. The expression of several wound-inducible genes was suppressed after the application of OS from two lepidopteran herbivores, Pieris brassicae and Spodoptera littoralis. This inhibition was correlated with enhanced S. littoralis larval growth, pointing to an effective role of insect OS in suppressing plant defences. Two genes, an ERF/AP2 transcription factor and a proteinase inhibitor, were then studied in more detail. OS-induced suppression lasted for at least 48 h, was independent of the jasmonate or salicylate pathways, and was not due to known elicitors. Interestingly, insect OS attenuated leaf water loss, suggesting that insects have evolved mechanisms to interfere with the induction of water-stress-related defences.Unfunde
IoT embedded software manipulation
No full textThe Internet of Things (IoT) has raised cybersecurity and privacy issues, notably about altering embedded software. This poster investigates the feasibility of using Read-Only Memory (ROM) at a low level to modify IoT devices while remaining undetectable to users and security systems. The study explores the vulnerabilities in embedded code and firmware, which are frequently proprietary and inaccessible, making them challenging to safeguard efficiently. The methodology uses a black-box forensic technique to acquire software, identify functions, and create test cases to assess potential alterations. The findings aim to contribute to a better understanding of IoT security concerns, emphasising the importance of upgraded firmware protection methods. This research highlights the challenges of detecting low-level attacks on IoT devices and provides insights into improving embedded system security.Unfunde
L1 scheme for semilinear stochastic subdiffusion with integrated fractional Gaussian noise
Get PDF© 2025 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).This paper considers a numerical method for solving the stochastic semilinear subdiffusion equation which is driven by integrated fractional Gaussian noise and the Hurst parameter H∈(1/2,1). The finite element method is employed for spatial discretization, while the L1 scheme and Lubich’s first-order convolution quadrature formula are used to approximate the Caputo time-fractional derivative of order α∈(0,1) and the Riemann–Liouville time-fractional integral of order γ∈(0,1), respectively. Using the semigroup approach, we establish the temporal and spatial regularity of the mild solution to the problem. The fully discrete solution is expressed as a convolution of a piecewise constant function with the inverse Laplace transform of a resolvent-related function. Based on the Laplace transform method and resolvent estimates, we prove that the proposed numerical scheme has the optimal convergence order O(τmin{H+α+γ−1−ε,α}),ε>0. Numerical experiments are presented to validate these theoretical convergence orders and demonstrate the effectiveness of this method.This work was supported by the Shanxi Provincial Natural Science Foundation under grants No. 202103021224317 and 2022RC11
Medium (un)specificity as material agency – the productive indeterminacy of matter/material (Russian Translation)
No full textThis is a Russian translation of my journal article ‘Medium (Un)specificity as Material Agency-The Productive Indeterminacy of Matter/Material’ which was originally published by Taylor & Francis in Textile: Cloth and Culture on 22/03/2018, available online: https://www.tandfonline.com/doi/full/10.1080/14759756.2018.1432133
In April 2023 I was contacted by Liudmila Aliabieva the Russian editor of Fashion Theory: The Journal of Dress Body and Culture with a request to translate the above article. Published since 2006 (4 issues a year) the Russian journal of Fashion Theory is a partner with the English-language Fashion Theory and has an agreement with its publisher Taylor and Francis to translate papers from its journals on Fashion Theory, Fashion Practice, and Textile Culture. Fashion Theory: The Journal of Dress Body and Culture is the only journal in Russia with an academic approach to fashion and is unique in treating fashion as a cultural phenomenon. It is published by an independent non-state publisher that adopts a strong humanist position and believes in the importance of international cultural and academic exchange. My article is in a section of the journal entitled ‘Focus’. Whilst my own discipline is fine art rather than fashion, the article developed out of a paper presented at 'The Matter of Material' conference convened by Lesley Millar Professor of Textile Culture at the University for the Creative Arts. Hosted by Turner Contemporary in Margate in April 2017, the conference brought together academic researchers, makers, and curators to discuss the role of textiles in contemporary art practice. The conference was a parallel event to 'Entangled: Threads & Making' (28 Jan - 7 May 2017), a major exhibition of sculpture, installation, tapestry, textiles which included artists from different generations and cultures who challenge established categories of craft, design, and fine art, and who share a fascination with the handmade and the processes of making itself.In this article, I consider some of the debates brought to the fore by the proliferation of recent textile focused exhibitions; namely the tension between a continued allegiance to medium specific conventions and the richness, hybridity and heterogeneity afforded by the post-medium condition of contemporary art. Through a new body of sculptural and installational practice I propose a constellatory opening up of textile in which the medium specific can be (re)mapped in a fluid and fragmentary way. Drawing particular reference from Adorno’s conception of the constellation and mimetic comportment, this model of practice involves a mode of behaviour that actively opens up to alterity and returns authority to the affective indeterminacy of the sensuously bound experiential encounter. This is manifest through a range of practice strategies - “thingness”, “staged (dis)contiguity”, and the play between “sensuous immediacy and corporeal containment” - which mobilise a precarious relationship between processes of attachment and detachment. Acknowledging the critical currency afforded to textile through feminist and poststructuralist critique, the work moves away from “a rhetoric of negative opposition” and predetermined discursive frameworks, returning authority to the aesthetic impulse, privileging the ambiguous resonances of an abstract sculptural language over more overt strategies of representation.Unfunde
The value of experiments in futures and foresight science as illustrated by the case of scenario planning
Get PDF© 2022 The Authors. Futures & Foresight Science published by John Wiley & Sons Ltd.An already pressing need to evidence the effectiveness of futures and foresight tools has been further amplified by the coronavirus pandemic, which highlighted more mainstream tools' difficulty with uncertainty. In light of this, the recent discussion in this journal on providing futures and foresight science with a stronger scientific basis is welcome. In this discussion critical realism has been proffered as a useful philosophical foundation and experiments a useful method for improving this field's scientific basis. Yet, experiments seek to isolate specific causal effects through closure (i.e., by controlling for all extraneous factors) and this may cause it to jar with critical realism's emphasis on uncertainty and openness. We therefore extend the recent discussion on improving the scientific basis of futures and foresight science by doing three things. First, we elaborate on critical realism and why the experimental method may jar with it. Second, we explain why the distinction between a conceptual and a direct replication can help overcome this jarring, meaning experiments can still be a valuable research tool for a futures and foresight science underpinned by critical realism. Third, we consider the appropriate unit of analysis for experiments on futures and foresight tools. In so doing, we situate the recent discussion on improving the scientific basis of futures and foresight science within the much longer running one on improving the scientific basis of business, management and strategy research more broadly. We use the case of scenario planning to illustrate our argument in relation to futures and foresight science.This research was undertaken as part of a project titled ‘The effect of scenario planning on individuals' perceptions of uncertain futures’, which was funded by the SAMS/BAM Research and Capacity Building Grant Scheme. It was thus jointly funded by the Society for the Advancement of Management Studies (SAMS) and the British Academy of Management (BAM)
A reassessment of the Galli and the Archigalli of Magna Mater, their differences and their citizen status in Rome
Get PDFThis article has been published in a revised form in The Classical Quarterly [http://doi.org/10.1017/S0009838825100736]. This version is published under a Creative Commons CC-BY-NC-ND licence. No commercial re-distribution or re-use allowed. Derivative works cannot be distributed. © copyright holder.Academics have regularly debated the question of how the Galli, priests of Magna Mater/Cybele, fit into the Roman social milieu. Several have argued that membership of the Galli was restricted to foreign citizens only (citing Domitian’s legislation) whilst others have argued that the chief priests—the Archigalli—were Roman citizens, while the ‘lower’ Galli were non-citizens, thus separating both within the Cybele cult. These views remain prevalent in modern discussions on the cult, and have not undergone significant scrutiny or analysis. By assessing these views and the existing material and literary evidence for the Galli, this article argues that the Archigalli and Galli were indistinct in terms of behaviour and affiliation. Moreover, this article uses archaeological and literary evidence to suggest that the Galli most likely included Roman citizens among their members, contrasting with the prevailing view of them as foreign residents in Rome.N/
Iterated ultrapowers for the masses
Get PDF© The Author(s) 2017. This article is an open access publication.We present a novel, perspicuous framework for building iterated ultrapowers. Furthermore, our framework naturally lends itself to the construction of a certain type of order indiscernibles, here dubbed tight indiscernibles, which are shown to provide smooth proofs of several results in general model theory.Unfunde
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