Push-pull Strategies Research Articles

Scientific approach in justification of monitoring and bioremediation of natural reservoirs in the suburban area

The relevance of the study is explained by the need to form a scientific approach to monitoring and bioremediation of pond reservoirs located in suburban areas. Further climate change, population growth, and excessive water intake lead to a decrease of restoration functions of water bodies and an increase of the HAB (Harmful Algal Bloom) effect. Suburban areas combine features of rural and urban lifestyles. At these territories, pond fish farming is intensively developed, and a space-time continuum with Push-pull strategies is being formed. The fishery complex of the Russian South is on the rise. It constantly requires applying of innovations. The essence of the research hypothesis was to define economic motivators for the development of pond fish farming in a suburban area, and to substantiate scientific approach to monitoring and bioremediation of water bodies. The represented materials reveal the tools for the development and using of automated devices and smart technologies in biosphere monitoring. Also the materials describe the tools for promotion of environmentally friendly technologies (bioremediation in the pond business). It is shown that such key requirements as mobility, efficiency, and using of green technologies, including bioremediation, become more and more significant for the development of pond fish farming in suburban areas. =

The Influence of Ring Roads on Traffic Characteristics in Urban Cities

Constructing ring roads is a traditional approach to alleviating traffic congestion in urban areas and enhancing road capacity. However, this solution is frequently inefficient in the long run. This study investigates different strategies for managing traffic congestion in urban areas and evaluates their efficacy. The text examines three situations where various methods were employed to address traffic congestion issues. These strategies are categorized into three distinct categories. The initial concept encompasses substantial engineering interventions, such as the establishment of ring roads, the creation of new roadways, and the enlargement of preexisting roads. Many cities are implementing push-and-pull strategies to optimize existing capacities and promote environmentally friendly transportation alternatives, thereby reducing car usage. These strategies include promoting public transportation, cycling, and walking, as well as modifying urban land use patterns to minimize the need for people to travel. These methods are successful in delivering long-lasting transportation solutions. Nevertheless, more than push-pull strategies are needed to adequately address traffic congestion, necessitating extensive engineering interventions to expand road capacity, particularly in cases of severe traffic in urban areas. The integration of these methods is categorized as the third principle. The utilization of ring roads also gives rise to numerous novel challenges, particularly in metropolitan areas. The predominant issue lies in the unregulated expansion of houses (urban sprawl) and inadequate public transportation. The problems identified of significant magnitude include Interconnectivity between different regions, the point where ring roads intersect, accessibility to housing, settlement amenities, and social challenges. The study determined that the third concept to tackle traffic congestion could be the most efficient approach for constructing ring roads in urban areas. To address the difficulties involved in the construction and development of circular roads, it would be beneficial to establish an organization that facilitates coordination among all stakeholders involved in the development of ring roads right from the outset. Urban Planning Directorates at the governorate level are responsible for carrying out this work in urban cities. In addition, rigorous enforcement of laws is also crucial for achieving desired goal.

How Effective Are Push-Pull Semiochemicals as Deterrents for Bark Beetles? A Global Meta-Analysis of Thirty Years of Research.

Bark beetles (Coleoptera: Curculionidae: Scolytinae) are among the most damaging tree pests globally. Rising temperatures, drought, fire, storms, cyclones, and poor forest management cause stress and loss of vigour in trees, and these conditions favour bark beetle outbreaks. While research has been conducted on push-pull strategies to deter bark beetles, using attractive and deterrent semiochemicals, the potential of this strategy to reduce bark beetle populations, particularly in the genera Dendroctonus and Ips, remains uncertain. Here, we conducted a global meta-analysis of 52 research articles to quantify the effects of semiochemical treatments on managing different species of Dendroctonus and Ips for forest protection. Based on this analysis, we found that push-pull semiochemicals can significantly reduce Dendroctonus and Ips populations measured by a reduction in the attraction to lure/trap catches, tree mortality, and attacks on trees. The overall efficacy of the push-pull semiochemical treatment shows a 66% reduction for Ips compared to control and a 54% reduction compared to control for Dendroctonus, while, at the species level, there was a 69% reduction for Dendroctonus ponderosae (Hopkins) and a 94% reduction in Ips perturbatus (Eichhoff), and a 93% reduction in Ips latidens (LeConte). Interestingly, among different treatment sources, the efficacy of conspecific semiochemicals in combination with heterospecific semiochemicals and non-host volatiles showed a 92% reduction in Dendroctonus spp., and conspecific semiochemicals in combination with non-host volatiles showed a 77% significant reduction in Ips spp., while the efficacy of heterospecific semiochemicals in reducing Ips population was about 69%, and 20% in Dendroctonus. Among different ecological regions, the use of a push-pull strategy showed a 70% reduction in Dendroctonus in central-west North America, and Ips showed a 75% reduction in southwest North America. Our results demonstrate that semiochemical-based push-pull techniques have the potential to reduce Dendroctonus and Ips bark beetle populations. Furthermore, based on our analysis, the efficacy of such eco-friendly interventions could be further improved and provide a good tool for forest managers to control these pests, at least under some circumstances.

Olfactory behavioral responses of two Drosophila species and their pupal parasitoid to volatiles from bananas.

Behavior-based manipulation is an essential part of Drosophila integrated pest management (IPM). Effective compounds are useful for improving the efficiency of baits and the development of attract-and-kill or push-pull strategies to manage Drosophila populations. Here, we investigated the olfactory behavior of two Drosophila species, as well as their pupal parasitoid, to volatiles from bananas, for the identification of effective compounds to control fly populations. The results showed that overripe bananas were most attractive to both flies, with a higher attraction index (AI) in Drosophila melanogaster than in Drosophila suzukii. The profiles of volatile organic compounds (VOCs) from bananas with three different ripening stages were compared, and six VOCs were selected for behavioral tests. D. suzukii showed significantly different responses to isoamyl alcohol with D. melanogaster. The effects of ethyl butyrate and ethyl isovalerate on the two flies were dose-dependent, with lower concentrations acting as repellent and higher concentrations acting as attractant. Isoamyl acetate, isoamyl butyrate and isoamyl isovalerate (0.005-0.05% v/v) were attractive to both flies. The parasitoid wasp Pachycrepoidus vindemmiae was repelled by isoamyl alcohol and ethyl butyrate, and attracted by ethyl isovalerate, but showed no significant response to isoamyl acetate, isoamyl butyrate and isoamyl isovalerate at the tested concentration. This study indicated that the behavioral response of Drosophila to the odor of chemical compounds is dose-dependent. Isoamyl alcohol and isoamyl acetate at certain concentrations could be used as repellents, whereas ethyl isovalerate as an attractant in control strategy design for D. suzukii. © 2023 Society of Chemical Industry.

6 Evaluating the Impacts of Starvation on Permethrin Resistant and Susceptible Horn Flies (Diptera: Muscidae)

Abstract The objective of the current study is to evaluate the impact of induced starvation on horn fly susceptibility to permethrin and general reproduction using filter paper and manure bioassays, respectively. Incorporating push-pull systems for horn fly control has recently gained much attention for use in managing this pest. However, the consequences of temporary starvation associated with the relocation of horn flies from one host to another have yet to be fully explored. Susceptible (SS) and permethrin resistant (PR) horn flies were randomly allocated to one of four treatment groups: 1- blood fed, 2- partially starved (4hr), 3- moderately starved (8hr), and 4- severely starved (12hr). Permethrin resistant flies were 1,227 times more (P < 0.05) tolerant to permethrin in comparison to SS flies. Furthermore, SS blood fed flies were 1.18, 1.89, and 3.12 times more tolerant to permethrin than SS flies starved for 4, 8, and 12 hours, respectively. Egg hatching rates decreased (P < 0.04) for 8hr and 12hr starved flies in comparison to blood fed flies. Larval development, as measured through manure bioassays was lower (P = 0.02) in severely starved flies in comparison to blood fed flies. Pupae sizes were unaffected (P = 0.58) by starvation and fly strain. These results indicate that susceptibility to permethrin increases as time without a blood meal increases and furthermore, offspring success is reduced specifically through egg viability. Findings from this work will help further expand current integrated pest management options for animal producers by increasing our understanding and implementation of push-pull strategies in animal production systems.

Protecting forest edges using trap logs – Limited effects of associated push-pull strategies targeting Ips typographus

Bark beetles can cause epidemic outbreaks and kill millions of cubic meters of economical and ecologically important forests around the world. It is well known what attracts and what repels different species of bark beetle, and these chemical cues can be used to protect trees and catch the beetles without using pesticides. Applying this knowledge, we investigated the use of push–pull strategies with trap logs along susceptible edges of a Swedish boreal spruce forest. The repellents (push) used were non-host volatiles (NHV) attached to tree trunks at the forest edge, and the attractants (pull) was a commercial aggregation pheromone attached to trap logs. The aim was to test whether the Ips typographus catch could be significantly increased by combining a push–pull system with traditional trap logs, thereby providing additional protection. The experiment was performed over two years and included the main flight period of I. typographus. The study sites were clear-cuts that had been harvested the preceding winter, and sun-exposed forest edges of mature spruce were targeted for protection. A full factorial setup was used comprising two treatments (repellent and attractant) and a control. Seven replicates of the trap logs were used, three during the first year and four during the second. The number of established I. typographus maternal galleries per square meter of log surface was used as the response variable. The trap logs captured large numbers of I. typographus, at an average density of 353 and 169 maternal galleries per m2 during year 1 and year 2, respectively, over all treatments. Based on the catch data, with a sufficient number of trap logs, the risk of tree mortality at forest edges may be reduced and we recommend its general use. However, we did not see any significant effect of either the repellent or the attractant on the density of maternal galleries. Hence, we cannot recommend the addition of chemical cues to improve the efficiency of trap logs. Although trap logs are efficient in capturing bark beetles and hence may protect forest edges, it does not imply that they can provide protection on a larger scale. In line with other studies, we hence recommend that forest management to target nature-based solutions that strengthen the resilience of forest stands, by using mixed forest stands and resistant plant species, and nurture habitats for natural predators of I. typographus.

Three chemosensory proteins from the sweet potato weevil, Cylas formicarius, are involved in the perception of host plant volatiles.

Chemosensory proteins (CSPs) play important roles in chemical communication, but their precise physiological functions are still unclear. Cylas formicarius is the most serious pest attacking sweet potato around the world. At present, there is no effective way to control this pest. Our results showed that CforCSP1, 5 and 6 genes were highly expressed in the antennae of both sexes of C. formicarius. In addition, results from a fluorescence competitive binding assay showed that the CforCSP1, 5 and 6 proteins had high binding affinities for 17 plant volatiles including eight host plant volatiles. This indicated that the three proteins may be involved in the detection of host plant volatiles. Furthermore, results from four-arm olfactometer bioassays showed that there was a significant tendency for C. formicarius to be attracted to eucalyptol, β-carotene, benzaldehyde, vanillin and phenethyl alcohol, while it was repelled by β-ionone. Finally, the levels of expression of the three CforCSPs in C. formicarius were successfully inhibited by RNA interference (RNAi). Behavioral experiments showed that CforCSP1, 5 and 6-deficient C. formicarius were partly anosmic to β-cyclocitral, benzaldehyde, octyl aldehyde, and β-ionone and exhibited a reduced ability to locate the host plant volatiles β-carotene and vanillin. Our data suggest that CforCSP1, 5 and 6 likely are involved in the chemical communication between C. formicarius and host plant volatiles, which may play pivotal roles in oviposition and feeding site preferences. More importantly, these results could provide information for the development of monitoring and push-pull strategies for the control of C. formicarius. © 2021 Society of Chemical Industry.

Push-pull effect on the charge transport characteristics in V-shaped organic semiconductor materials

With the goal to tune charge transport and electronic properties of 4,6-di(thiophen-2-yl)pyrimidine (DTP) structure, seven novel V-shaped organic semiconductor compounds were designed by nitrogen doping, oligocenes π-bridge incorporations and push-pull strategy. Primarily, 4,6-bis-thiazol-2-yl-pyrimidine (1) was designed by nitrogen atoms doping in DTP. Then push-pull system named 1DA was designed by substituting –N(CH3)2 at R1 and R2, while –CF3 at R3 and R4 positions of 1. Moreover, various semiconducting materials (2DA-6DA) with tuned properties were designed from 1DA by fusing benzene, naphthalene, anthracene, tetracene and pentacene at both ends. The density functional theory (DFT) and time-dependent DFT were adopted for optimizing the ground and excited state structures, correspondingly. We investigated frontier molecular orbitals, photo-stability, electron injection, electron affinity (EA), ionization energies (IE) and reorganization energies. The push-pull and π-bridge elongation strategies ominously raise EA while diminish IE values, which may lead to decrease the electron and hole injection obstruction. Besides, donors–acceptors and oligocenes at both ends meaningfully drop the electron reorganization energy values as compared to normally used n-type material, i.e., tris(8-hydroxyquinolinato)aluminium (mer-Alq3). These results revealed that newly designed materials 4DA-6DA would be proficient to be used in n-type semiconductor devices.

Design Rules for Transparent Push-Pull Electron Acceptors: A Case Study on Perylenediimide Derivatives.

Transparent photovoltaics are receiving increased attention for their wide range of applicability, but there have been few attempts to systematically tune organic materials to achieve transparency. In this Letter, we study the influence of simple structural modifications on the photoabsorption spectrum of the nonfullerene electron acceptor perylenediimide. Motivated by push-pull design strategies, we explore the effects of applying electron-donating functional groups with varying strengths using three design motifs. We demonstrate that relative Mulliken electronegativity, which can be easily computed using an optimally tuned screened range-separated hybrid functional, is a useful metric for finding suitable donor groups. We also demonstrate that donor groups that include a conjugated spacer are crucial to obtaining a planar molecule with uniform conjugation and low-energy charge-transfer excitations. These simple design rules can be used to design near-infrared absorbing transparent electron acceptors based on perylenediimide and other promising molecular platforms.

Evaluating Behavioral Responses of Selected Stink Bugs (Hemiptera: Pentatomidae) to Spinosad

Southern green stink bug, Nezara viridula (L.) and redbanded stink bug, Piezodorus guildinii (Westwood) are two of the most important seed sucking pests affecting Louisiana soybean production and rice stink bug, Oebalus pugnax (F.) is an important late season pest in Louisiana rice. Exploration of chemicals that exhibit attraction or repellent activities toward major stink bug species would be beneficial in developing push-pull strategies. Spinosad is a commercially available natural insecticide that may have arrestant, attractant, or phagostimulant properties against stink bugs. To test this, a series of laboratory experiments were conducted to investigate the tactile, olfactory, and feeding responses of these stink bugs toward two commercial spinosad products (Entrust and Tracer) and technical grade spinosad. In tactile assays, female and male redbanded stink bug were arrested by Entrust, Tracer, and technical grade spinosad, whereas only rice stink bug and southern green stink bug males were arrested by Entrust. Y-tube assays revealed no attraction to any of the products by either male or female rice stink bug, redbanded stink bug, or southern green stink bug. In paired (treated or untreated soybean seed) feeding preference experiments, southern green stink bug showed no preference for any treatment, whereas redbanded stink bug fed more on Entrust- and Tracer-treated seed. From these results, spinosad appears to have an arrestant and phagostimulant effect on redbanded stink bug in the laboratory.

An odorant receptor from Anopheles gambiae that demonstrates enantioselectivity to the plant volatile, linalool.

Insects express chemical receptors within sensory neurons that are activated by specific cues in the environment, thereby influencing the acquisition of critical resources. A significant gap in our current understanding of insect chemical ecology is defining the molecular mechanisms that underlie sensitivity to plant-emitted volatiles. Linalool is a commonly-occurring monoterpene that has various effects on insect behavior, either acting as an attractant or a repellent, and existing in nature as one of two possible stereoisomers, (R)-(–)-linalool and (S)-(+)-linalool. In this study, we have used a cell-based functional assay to identify linalool and structurally-related compounds as ligands of Odorant receptor 29, a labellum-expressed receptor in the malaria vector mosquito, Anopheles gambiae (AgamOr29). While (R)-(–)-linalool activates AgamOr29, a mixture of the (R) and (S) stereoisomers activates the receptor with higher potency, implying enantiomeric selectivity. Orthologs of Or29 are present in the genomes of Anophelines within the Cellia subgenus. The conservation of this receptor across Anopheline lineages suggests that this ecologically important compound might serve as an attraction cue for nectar-seeking mosquitoes. Moreover, the characterization of a mosquito terpene receptor could serve as a foundation for future ligand-receptor studies of plant volatiles and for the discovery of compounds that can be integrated into push-pull vector control strategies.

Commercially Available Essential Oil Formulas as Repellents Against the Stored-Product Pest Alphitobius diaperinus.

The main aim of the presented paper is to assess the potential repellent effect of selected essential oils (EOs) against the lesser mealworm (Alphitobius diaperinus), which can cause economic losses in storage and in the poultry industry. Due to the development of pesticide resistance in A. diaperinus populations, as well as an attempt to limit extensive use of potentially harmful pesticides in food-related industries, there is a strong need for the development of alternative methods of dealing with A. diaperinus infestations. Because of their cost-effectiveness, availability and low vertebrate toxicity, EOs are promising agents in pest management. In the presented paper four off-the-shelf EOs: mint, vanilla, lemon and citronella (and mixtures of them) were tested as potential repellents. Moreover, a novel preference assay, providing an extended analysis of the preference and the locomotor response, was used. The most effective EOs were: citronella and lemon. EOs mixtures were generally more repellent than individual EOs, with the lemon and vanilla 1:1 mixture acting as the strongest repellent. A few of the tested EOs caused significant alterations to the locomotor activity, although no direct relation was observed. In conclusion, EOs can be potentially used as repellent agents in A. diaperinus management. Additionally, data on the locomotor activity may lead to designing better push-pull strategies in pest management.

松瘿小卷蛾及其寄生蜂对落叶松挥发物的嗅觉行为反应

PDF HTML阅读 XML下载 导出引用 引用提醒 松瘿小卷蛾及其寄生蜂对落叶松挥发物的嗅觉行为反应 DOI: 10.5846/stxb201901090080 作者: 作者单位: 东北林业大学林学院,东北林业大学林学院,大兴安岭森保站,东北林业大学林学院,东北林业大学林学院 作者简介: 通讯作者: 中图分类号: 基金项目: 中央高校基本科研业务费专项资金（2572019CP11）；黑龙江省重点科技攻关项目（GA09B203-5） Olfactory responses of Cydia zebeana adults and their parasitic wasps to larch volatiles Author: Affiliation: College of Forestry,Northeast Forestry University,Harbin,College of Forestry,Northeast Forestry University,Harbin,Forest Protection Station of Greater Khingan Range,Jiagedaqi,College of Forestry,Northeast Forestry University,Harbin,College of Forestry,Northeast Forestry University,Harbin Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为确定松瘿小卷蛾（Cydia zebeana）对寄主的定位习性，以及探讨对其的综合防治方法，通过Y型管嗅觉仪行为选择实验，分析松瘿小卷蛾及其两种寄生性天敌小卷蛾革腹茧蜂（Ascogaster olethreuti）和卷蛾长体茧蜂（Macrocentrus sp.）对寄主兴安落叶松（Larix gmelinii）的9种不同浓度挥发物的行为反应。结果表明，对雌蛾产生引诱作用的挥发物为3-蒈烯、水芹烯，产生驱避作用的挥发物为月桂烯、罗勒烯、莰烯；（R）-α-蒎烯表现为低浓度引诱高浓度驱避。对雄蛾产生引诱作用的挥发物为（S）-β-蒎烯，产生驱避作用的挥发物为月桂烯、3-蒈烯、（S）-α-蒎烯、莰烯。对小卷蛾革腹茧蜂有引诱作用的挥发物为（S）-β-蒎烯、（S）-α-蒎烯、叶醇，产生驱避作用的挥发物为罗勒烯、莰烯、水芹烯；对卷蛾长体茧蜂有引诱作用的挥发物为（S）-β-蒎烯、（S）-α-蒎烯、（R）-α-蒎烯、叶醇，产生驱避作用的挥发物为罗勒烯、水芹烯。说明在利用推拉策略防控松瘿小卷蛾时，月桂烯、叶醇和（S）-α-蒎烯可用于保护目标林，驱避害虫吸引天敌；水芹烯可以结合化学防治施用于饵木林，诱杀害虫而驱避寄生蜂。 Abstract:In order to determine the olfactory-behavioral mechanisms underlying the host-finding of Cydia zebeana and to explore environmentally sound IPM control methods, the behavioral responses of C. zebeana adults (virgin females and males) and its two parasitic wasps, Ascogaster olethreuti and Macrocentrus sp. to different concentrations of nine larch volatiles (Larix gmelinii, both bark and needle volatiles) were tested in the laboratory using Y-tube olfactomter. The results showed that females of C. zebeana were significantly attracted to (+)-3-carene and (R)-(-)-α-phellandrene, and were strongly repelled by myrcene, ocimene, and camphene. (R)-α-pinene was attractive at low concentrations, but repellent at high concentrations. In contrast, C. zebeana males were attracted to (S)-β-pinene, and repelled by myrcene, (+)-3-carene, (S)-α-pinene and camphene. A. olethreuti adults were attracted to (S)-β-pinene, (S)-α-pinene and phytol, while they were repelled by ocimene, camphene, and (R)-(-)-α-phellandrene. Macrocentrus sp. were attracted to (S)-β-pinene, (S)-α-pinene, phytol and (R)-α-pinene. They were also repelled by ocimene and (R)-(-)-α-phellandrene. As a part of push-pull control strategies against C. zebeana, myrcene, phytol, and (S)-α-pinene can be applied to the target forests to repel the moths, and to attract their parasitoid wasps, whereas (R)-(-)-α-phellandrene can be applied to the bait trees in combination with insecticide sprays to attract the moths and to repel parasitoid wasps. 参考文献 相似文献 引证文献

Control of Cockroaches (Blattaria) in Sewers: A Practical Approach Systematic Review.

Periplaneta americana (L.) (Blattaria: Blattidae), the American cockroach, is the most important invasive urban pest of sewer environments colonizing there with high significance of human public health and household allergens need to be controlled. Therefore this practical approach systematic review perform internationally to highlight and provide a detailed P. americana control in sewers. Of the 474 papers, 129 papers were selected to become this practical approach systematic review study of cockroach control in sewers. To control the American cockroaches, many studies have been conducted in various fields describing from an angle. The results were classified and discussed in getting cockroaches from sewers into buildings and their elimination, insecticide susceptibility, application of dust, bait and Inesfly paint insecticide formulations, biocontrol, and futuristic action categories. A recommending manner to achieve a successful P. americana cockroach control in sewers is using a combination of Integrated Pest Management (IPM) strategies resulted in significant reductions of cockroach infestations and asthma health outcomes. Use of P. americana breeding thelytoky, push-pull strategies and an automated sewer robot, and integrating health into the future buildings may be new approaches of P. americana control strategies.

71 Physical and chemical house entry barriers to enhance odour-baited trapping for malaria control

Background: Odour-baited mosquito trapping is a promising new malaria intervention that lures, traps and kills mosquitoes. However, mosquitoes still bypass the trapping system and enter easily accessible African households through the open eaves. In this study, house screening and a spatial repellent were used as a physical and chemical house entry barrier to determine whether these interventions can protect people from malaria mosquitoes by decreasing mosquito house entry and simultaneously increasing odourbaited trapping efficacy. Methods: In an experimental greenhouse in Kenya, two semi-field experiments were conducted. In the first experiment, three physical house adjustment interventions were tested against using no intervention: house screening (block); odour-baited trapping (pull) and both interventions (block-pull). In the second experiment, three chemical interventions were tested against using no intervention: a cotton band around the eaves impregnated with the spatial mosquito repellant Delta-undecalactone (push); odourbaited trapping (pull) and both interventions (push-pull). The effects of interventions were evaluated by comparing mean trap catches of the odour-baited trap outside, and mean mosquito house entry. Results: In the first experiment (block-pull), the chance of a mosquito getting caught by an odour-baited trap more than doubled (OR=2.163) when complementing odour-baited trapping with house screening (P<0,001). All interventions significantly reduced mosquito house entry (p<0,001), with the strongest protective effect for the combined intervention of house screening and odour-baited trapping (OR=0.10). The interventions of the second experiment did not have a significant effect on odour-baited trap catches (p=0.584), nor mosquito house entry (p>0.172). Discussion: This study shows that house screening could be a valuable addition to odourbaited mosquito trapping for malaria control and confirmed the strong effect of house screening on mosquito house entry. In contrast to other studies, a chemical barrier of Delta-undecalactone did not improve the protection against malaria mosquitoes. However, push-pull strategies might still be a viable alternative to house screening, since the absence of an effect might have been caused by an interaction of the intervention with the experimental environment.

A herbivore-induced plant volatile interferes with host plant and mate location in moths through suppression of olfactory signalling pathways.

BackgroundPlants under herbivore attack release volatiles that attract natural enemies, and herbivores in turn avoid such plants. Whilst herbivore-induced plant volatile blends appeared to reduce the attractiveness of host plants to herbivores, the volatiles that are key in this process and particularly the way in which deterrence is coded in the olfactory system are largely unknown. Here we demonstrate that herbivore-induced cotton volatiles suppress orientation of the moth Spodoptera littoralis to host plants and mates.ResultsWe found that (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT), an induced volatile, is key in herbivore deterrence: DMNT suppressed plant odour- and pheromone-induced behaviours. We then dissected the neurophysiological basis of this interaction. DMNT-responding glomeruli were also activated by other plant compounds, suggesting that S. littoralis possesses no segregated olfactory circuit dedicated exclusively to DMNT. Instead, DMNT suppressed responses to the main pheromone component, (Z)-9-(E)-11-tetradecenyl acetate, and primarily to (Z)-3-hexenyl acetate, a host plant attractant.ConclusionOur study shows that olfactory sensory inhibition, which has previously been reported without reference to an animal’s ecology, can be at the core of coding of ecologically relevant odours. As DMNT attracts natural enemies and deters herbivores, it may be useful in the development or enhancement of push-pull strategies for sustainable agriculture.Electronic supplementary materialThe online version of this article (doi:10.1186/s12915-015-0188-3) contains supplementary material, which is available to authorized users.

Evaluation of a Push-Pull Approach for Aedes aegypti (L.) Using a Novel Dispensing System for Spatial Repellents in the Laboratory and in a Semi-Field Environment.

The increase in insecticide resistant mosquito populations necessitates the exploration of novel vector control intervention measures. Push-pull strategies for insect control have been successful when used in integrated crop pest management. Through the combinatory use of deterring and attracting stimuli, the abundance of insect pests can be changed in a given area. A push-pull strategy might also significantly reduce human-vector contacts and augment existing mosquito control strategies, e.g. through the combination of an attractive trapping system and a potent spatial repellent. Our approach includes the BG-Sentinel (BGS) trap in combination with catnip oil (Nepeta cataria), a known spatial repellent for Aedes aegypti. To impart a deterrent effect on mosquitoes at a distance, a homogenous and continuous dispersal of volatile repellent compounds is crucial. We have developed a repellent dispensing system that is easy to use and provides a homogenous dispersal of repellent in an air curtain. The use of five 9 V fans and custom-made repellent sachets containing 10% catnip essential oil created a repellent loaded air curtain that provided coverage of an area of 2 m2 (1.2 x 1.65 m). Air was sampled at four different heights in the curtain and analysed via thermal desorption (TD) and consecutive gas chromatography—mass spectrometry (GC-MS). Nepetalactone, the main constituent of the oil, was detected in air at a concentration range of 80 to 100 μg/m3 and the amounts were comparable at all four sampling positions. When a human volunteer was sitting behind the repellent curtain and a BGS trap was installed in front of the curtain in laboratory push-pull trials, Ae. aegypti landing collections decreased significantly by 50% compared to repellent-free controls. However, in a semi-field environment, comparable protective effects could not be achieved and further research on suitable repellent concentrations for outdoor implementation will be required.

Improvement of a synthetic lure for Anopheles gambiae using compounds produced by human skin microbiota

BackgroundAnopheles gambiae sensu stricto is considered to be highly anthropophilic and volatiles of human origin provide essential cues during its host-seeking behaviour. A synthetic blend of three human-derived volatiles, ammonia, lactic acid and tetradecanoic acid, attracts A. gambiae. In addition, volatiles produced by human skin bacteria are attractive to this mosquito species. The purpose of the current study was to test the effect of ten compounds present in the headspace of human bacteria on the host-seeking process of A. gambiae. The effect of each of the ten compounds on the attractiveness of a basic blend of ammonia, lactic and tetradecanoic acid to A. gambiae was examined.MethodsThe host-seeking response of A. gambiae was evaluated in a laboratory set-up using a dual-port olfactometer and in a semi-field facility in Kenya using MM-X traps. Odorants were released from LDPE sachets and placed inside the olfactometer as well as in the MM-X traps. Carbon dioxide was added in the semi-field experiments, provided from pressurized cylinders or fermenting yeast.ResultsThe olfactometer and semi-field set-up allowed for high-throughput testing of the compounds in blends and in multiple concentrations. Compounds with an attractive or inhibitory effect were identified in both bioassays. 3-Methyl-1-butanol was the best attractant in both set-ups and increased the attractiveness of the basic blend up to three times. 2-Phenylethanol reduced the attractiveness of the basic blend in both bioassays by more than 50%.ConclusionsIdentification of volatiles released by human skin bacteria led to the discovery of compounds that have an impact on the host-seeking behaviour of A. gambiae. 3-Methyl-1-butanol may be used to increase mosquito trap catches, whereas 2-phenylethanol has potential as a spatial repellent. These two compounds could be applied in push-pull strategies to reduce mosquito numbers in malaria endemic areas.

Reverse Logistics and Push-Pull Manufacturing Systems: The Case of Electronic Products

Research on the determinants of reverse logistics has so far largely been focussed on product characteristics. We argue in this exploratory article that these explanations are not sufficient as various reverse logistics strategies can be observed for similar products. We suggest to complement them by suggesting a more general model which takes into account push-pull manufacturing strategies. We illustrate the model with three case studies and suggest future avenues for empirical research based on our framework.

Push-pull strategies for vector control

In many disease vectors, olfaction is the principal modality with which food sources (plants and vertebrates) and oviposition sites are being identified [1]. Chemical cues emanating from these sources are detected from a distance, often inducing a behavioural response that leads the arthropod vector to the source. At close range, other sensual modalities such as vision, heat and moisture may affect this behaviour as well. Arthropods can identify these chemical cues from a long distance, in some cases over 100m or further. The most common odorant cue is carbon dioxide (CO2), which is recognised by most blood feeding arthropods. Other chemical odorants are more group- or even species-specific, for example tsetse flies respond to CO2 and blend of 1-octen-3-ol, 4-Methylphenol and 3-n-Propylphenol [2], malaria mosquitoes to ammonia, lactic acid and tetradecanoic acid [3] and yellow fever mosquitoes to ammonia, lactic acid and caproic acid [4]. Pathogens of human and animal disease make use of these odorants by hitchhiking with the vectors, to be passed on from one host to the next. The vertebrate hosts, therefore, produce chemicals that favour the transmission of infectious disease. While many animals produce odorants that are perceived as attractive by the arthropods, some odorants cause repellent effects, pushing the arthropods away from the source and thus protecting the animals against insect bites and potential disease transmission. Recent advances in chemical ecology have led to the development of technologies where pest insects, including disease vectors, can be manipulated by a skilful combination of attractants and repellents that lead the vectors to traps or killing devices. This push-pull strategy [5] has already caused significant reductions of transmission of trypanosomiasis, and it is considered as a control method targeting other vector-borne disease complexes. Exploitation of behavioural characteristics of the vectors hence leads to reduced disease transmission and, in some cases, even disease elimination. The presentation will discuss the state-of-the-art of this behavioural technology for vector-borne disease control, and provide an outlook for future prospects.