| 1. |
- Ahearn, Thomas U., et al.
(författare)
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Common variants in breast cancer risk loci predispose to distinct tumor subtypes
- 2022
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Ingår i: Breast Cancer Research. - : Springer Nature. - 1465-5411 .- 1465-542X. ; 24:1
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundGenome-wide association studies (GWAS) have identified multiple common breast cancer susceptibility variants. Many of these variants have differential associations by estrogen receptor (ER) status, but how these variants relate with other tumor features and intrinsic molecular subtypes is unclear.MethodsAmong 106,571 invasive breast cancer cases and 95,762 controls of European ancestry with data on 173 breast cancer variants identified in previous GWAS, we used novel two-stage polytomous logistic regression models to evaluate variants in relation to multiple tumor features (ER, progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2) and grade) adjusting for each other, and to intrinsic-like subtypes.ResultsEighty-five of 173 variants were associated with at least one tumor feature (false discovery rate < 5%), most commonly ER and grade, followed by PR and HER2. Models for intrinsic-like subtypes found nearly all of these variants (83 of 85) associated at p < 0.05 with risk for at least one luminal-like subtype, and approximately half (41 of 85) of the variants were associated with risk of at least one non-luminal subtype, including 32 variants associated with triple-negative (TN) disease. Ten variants were associated with risk of all subtypes in different magnitude. Five variants were associated with risk of luminal A-like and TN subtypes in opposite directions.ConclusionThis report demonstrates a high level of complexity in the etiology heterogeneity of breast cancer susceptibility variants and can inform investigations of subtype-specific risk prediction.
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| 2. |
- Kapoor, Pooja Middha, et al.
(författare)
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Combined associations of a polygenic risk score and classical risk factors with breast cancer risk
- 2021
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Ingår i: Journal of the National Cancer Institute. - : Oxford University Press (OUP). - 0027-8874 .- 1460-2105. ; 113:3, s. 329-337
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Tidskriftsartikel (refereegranskat)abstract
- We evaluated the joint associations between a new 313-variant PRS (PRS313) and questionnaire-based breast cancer risk factors for women of European ancestry, using 72 284 cases and 80 354 controls from the Breast Cancer Association Consortium. Interactions were evaluated using standard logistic regression and a newly developed case-only method for breast cancer risk overall and by estrogen receptor status. After accounting for multiple testing, we did not find evidence that per-standard deviation PRS313 odds ratio differed across strata defined by individual risk factors. Goodness-of-fit tests did not reject the assumption of a multiplicative model between PRS313 and each risk factor. Variation in projected absolute lifetime risk of breast cancer associated with classical risk factors was greater for women with higher genetic risk (PRS313 and family history) and, on average, 17.5% higher in the highest vs lowest deciles of genetic risk. These findings have implications for risk prevention for women at increased risk of breast cancer.
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| 3. |
- Middha, Pooja K., et al.
(författare)
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A genome-wide gene-environment interaction study of breast cancer risk for women of European ancestry
- 2023
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Ingår i: Breast Cancer Research. - : BioMed Central (BMC). - 1465-5411 .- 1465-542X. ; 25:1
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Tidskriftsartikel (refereegranskat)abstract
- Background Genome-wide studies of gene-environment interactions (GxE) may identify variants associated with disease risk in conjunction with lifestyle/environmental exposures. We conducted a genome-wide GxE analysis of similar to 7.6 million common variants and seven lifestyle/environmental risk factors for breast cancer risk overall and for estrogen receptor positive (ER +) breast cancer. Methods Analyses were conducted using 72,285 breast cancer cases and 80,354 controls of European ancestry from the Breast Cancer Association Consortium. Gene-environment interactions were evaluated using standard unconditional logistic regression models and likelihood ratio tests for breast cancer risk overall and for ER + breast cancer. Bayesian False Discovery Probability was employed to assess the noteworthiness of each SNP-risk factor pairs. Results Assuming a 1 x 10(-5) prior probability of a true association for each SNP-risk factor pairs and a Bayesian False Discovery Probability < 15%, we identified two independent SNP-risk factor pairs: rs80018847(9p13)-LINGO2 and adult height in association with overall breast cancer risk (ORint = 0.94, 95% CI 0.92-0.96), and rs4770552(13q12)-SPATA13 and age at menarche for ER + breast cancer risk (ORint = 0.91, 95% CI 0.88-0.94). Conclusions Overall, the contribution of GxE interactions to the heritability of breast cancer is very small. At the population level, multiplicative GxE interactions do not make an important contribution to risk prediction in breast cancer.
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| 4. |
- Stenberg, Johan A, et al.
(författare)
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When is it biological control? A framework of definitions, mechanisms, and classifications
- 2021
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Ingår i: Journal of Pest Science. - : Springer Science and Business Media LLC. - 1612-4758 .- 1612-4766. ; 94, s. 665-676
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Forskningsöversikt (refereegranskat)abstract
- Biological control, or biocontrol, is the exploitation of living agents (incl. viruses) to combat pestilential organisms (incl. pathogens, pests, and weeds) for diverse purposes to provide human benefits. Thus, during the last century the practices and concepts involved have evolved in separate streams associated with distinct scientific and taxonomic disciplines. In parallel developments, there have been increasing references to biological control in industrial contexts and legislation, resulting in conceptual and terminological disintegration. The aim of this paper is to provide a global conceptual and terminological platform that facilitates future development of the field. We review use of previously suggested terms in key fields (e.g., phytopathology, entomology, and weed science), eliminate redundant terminology, identify three principles that should underpin the concept, and then present a new framework for biological control, rooted in seminal publications. The three principles establish that (1) only living agents can mediate biological control, (2) biological control always targets a pest, directly or indirectly, and (3) all biocontrol methods can be classified in four main categories depending on whether resident agents are utilized, with or without targeted human intervention (conservation biological control and natural biological control, respectively) or agents are added for permanent or temporary establishment (classical biological control and augmentative biological control, respectively). Correct identification of what is, and is not, biological control can help efforts to understand and optimize biological pest control for human and environmental benefits. The new conceptual framework may contribute to more uniform and appropriate regulatory approaches to biological control, and more efficient authorization and application of biocontrol products.
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| 5. |
- Alsanius, Beatrix, et al.
(författare)
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The power of light from a non-phototrophic perspective: a phyllosphere dilemma
- 2024
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Ingår i: Frontiers in Photobiology. - 2813-8228. ; 2
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Tidskriftsartikel (refereegranskat)abstract
- Plants and crop stands are considered holobionts, colonized by both autotrophic and by non-phototrophic heterotrophic microbiota. The dilemma in the exisiting body of studies is that the focus is primarily directed towards environmental specificties relevant for phototrophic organisms (predominantly plants), but does not take into account non-phototrophs. By definition, non-phototrophic heterotrophic bacteria do not use light as an energy source. Light energy and wavelength are rather used as a signal that can provoke shifts in both their metabolism and microbial lifestyle. Reaction and recovery time can vary between organisms and is dependent on the organism’s physiological stage. The length of the lighting event affects the energy an organism is exposed to. We argue that to obtain a deeper and more distinct understanding of light exposure (irradiance, exposure length), quantity (light intensity), and quality (wavelength/spectral distribution, bandwidth at full-width half-maximum) related mechanisms on non-phototrophic bacteria in the phyllosphere, the light environment needs to be further strictly characterized. This includes information on the actual energy hitting planktonic or sessile non-phototrophic bacteria resident on and inside plants aboveground. Mapping the light environment in ecosystems aids in unraveling light-phyllosphere interactions and strengthens their transdisciplinary character. This issue is fundamental in order to revisit and repeat others’ experimental approaches and findings but also to be able to translate findings into further action.
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| 6. |
- Andreadis, Stefanos, et al.
(författare)
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Survey of arthropod assemblages responding to live yeasts in an organic apple orchard
- 2015
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Ingår i: Frontiers in Ecology and Evolution. - : Frontiers Media SA. - 2296-701X. ; 3
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Tidskriftsartikel (refereegranskat)abstract
- Associations between yeasts and insect herbivores are widespread, and these interkingdom interactions play a crucial role in yeast and insect ecology and evolution. We report a survey of insect attraction to live yeast from a community ecology perspective. In the summer of 2013 we screened live yeast cultures of Metschnikowia pulcherrima, M. andauensis, M. hawaiiensis, M. lopburiensis, and Cryptococcus tephrensis in an organic apple orchard. More than 3000 arthropods from 3 classes, 15 orders, and 93 species were trapped; ca. 79% of the trapped specimens were dipterans, of which 43% were hoverflies (Syrphidae), followed by Sarcophagidae, Phoridae, Lauxaniidae, Cecidomyidae, Drosophilidae, and Chironomidae. Traps baited with M. pulcherrima, M. andauensis, and C. tephrensis captured typically 2.4 times more specimens than control traps; traps baited with M. pulcherrima, M. hawaiiensis, M. andauensis, M. lopburiensis, and C. tephrensis were more species-rich than unbaited control traps. We conclude that traps baited with live yeasts of the genera Metschnikowia and Cryprococcus are effective attractants and therefore of potential value for pest control. Yeast-based monitoring or attract-and-kill techniques could target pest insects or enhance the assemblage of beneficial insects. Manipulation of insect behavior through live yeast cultures should be further explored for the development of novel plant protection techniques.
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| 7. |
- Becher, Paul, et al.
(författare)
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A Conserved Dedicated Olfactory Circuit for Detecting Harmful Microbes in Drosophila
- 2012
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Ingår i: Cell. - : Elsevier BV. - 0092-8674 .- 1097-4172. ; 151, s. 1345-1357
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Tidskriftsartikel (refereegranskat)abstract
- Flies, like all animals, need to find suitable and safe food. Because the principal food source for Drosophila melanogaster is yeast growing on fermenting fruit, flies need to distinguish fruit with safe yeast from yeast covered with toxic microbes. We identify a functionally segregated olfactory circuit in flies that is activated exclusively by geosmin. This microbial odorant constitutes an ecologically relevant stimulus that alerts flies to the presence of harmful microbes. Geosmin activates only a single class of sensory neurons expressing the olfactory receptor Or56a. These neurons target the DA2 glomerulus and connect to projection neurons that respond exclusively to geosmin. Activation of DA2 is sufficient and necessary for aversion, overrides input from other olfactory pathways, and inhibits positive chemotaxis, oviposition, and feeding. The geosmin detection system is a conserved feature in the genus Drosophila that provides flies with a sensitive, specific means of identifying unsuitable feeding and breeding sites.
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| 8. |
- Becher, Paul
(författare)
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Current knowledge of interactions between Drosophila suzukii and microbes, and their potential utility for pest management
- 2016
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Ingår i: Journal of Pest Science. - : Springer Science and Business Media LLC. - 1612-4758 .- 1612-4766. ; 89, s. 621-630
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Forskningsöversikt (refereegranskat)abstract
- Insects exhibit complex symbiotic interactions with microorganisms, which provide an opportunity for developing novel pest management strategies. Closely related to Drosophila melanogaster, which is commonly used as a model to explore insect-microbe interactions, Drosophila suzukii is an important invasive insect pest of fruit crops in the Americas and Europe. We provide an overview of Drosophila-microbe interactions and review current research with D. suzukii. Recent studies revealed yeast and bacterial species associated with D. suzukii flies, fly guts and infested fruit. The ecological importance of these insect-microbe interactions is under investigation. Microbes have a strong impact on insect physiology and D. suzukii responds both positively and aversively to microbial volatiles. We highlight potential pest management strategies that take advantage of D. suzukii-microbe ecology, including improved monitoring as well as management using behavioural manipulation, phagostimulants and biotechnology.
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| 9. |
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| 10. |
- Becher, Paul
(författare)
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Functional transcriptome analyses of Drosophila suzukii antennae reveal mating-dependent olfaction plasticity in females
- 2019
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Ingår i: Insect Biochemistry and Molecular Biology. - : Elsevier BV. - 0965-1748 .- 1879-0240. ; 105, s. 51-59
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Tidskriftsartikel (refereegranskat)abstract
- Insect olfaction modulates basal behaviors and it is often influenced by the physiological condition of each individual such as the reproductive state. Olfactory plasticity can be achieved by modifications at both peripheral and central nervous system levels. Here we performed a genome-wide transcriptomic analysis of the main olfactory organ, the antenna, to investigate how gene expression varies with female mating status in Drosophila suzukii, a destructive and invasive soft fruit pest. We observed a wide mating-induced up-regulation of chemosensory-related genes in females, especially odorant receptor (Or) genes. We then used a candidate gene approach to define the comprehensive dataset of antenna-expressed chemosensory receptors and binding proteins, which showed many similarities with Drosophila melanogaster. Candidate gene approach was also used to finely quantify differential expression at Or isoform level, suggesting post-mating transcriptional modulation of genes involved in the peripheral olfactory system. We identified 27 up-regulated Or transcripts encoded by 25 genes, seven of them were duplications specific to D. suzukii lineage. Post-mating olfactory modulation was further supported by electroantennogram recordings that showed a differential response according to mating status to one out of eight odors tested (isoamyl-acetate). Our study characterizes the transcriptional mechanisms driven by mating in D. suzukii female antennae. Understanding the role of genes differentially expressed in virgin or mated females will be crucial to better understand host finding and the crop-damaging oviposition behavior of this species.
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| 11. |
- Becher, Paul G., et al.
(författare)
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Chemical signaling and insect attraction is a conserved trait in yeasts
- 2018
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Ingår i: Ecology and Evolution. - : Wiley. - 2045-7758. ; , s. 2962-2974
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Tidskriftsartikel (refereegranskat)abstract
- Yeast volatiles attract insects, which apparently is of mutual benefit, for both yeasts and insects. However, it is unknown whether biosynthesis of metabolites that attract insects is a basic and general trait, or if it is specific for yeasts that live in close association with insects. Our goal was to study chemical insect attractants produced by yeasts that span more than 250 million years of evolutionary history and vastly differ in their metabolism and lifestyle. We bioassayed attraction of the vinegar fly Drosophila melanogaster to odors of phylogenetically and ecologically distinct yeasts grown under controlled conditions. Baker's yeast Saccharomyces cerevisiae, the insect-associated species Candida californica, Pichia kluyveri and Metschnikowia andauensis, wine yeast Dekkera bruxellensis, milk yeast Kluyveromyces lactis, the vertebrate pathogens Candida albicans and Candida glabrata, and oleophilic Yarrowia lipolytica were screened for fly attraction in a wind tunnel. Yeast headspace was chemically analyzed, and co-occurrence of insect attractants in yeasts and flowering plants was investigated through a database search. In yeasts with known genomes, we investigated the occurrence of genes involved in the synthesis of key aroma compounds. Flies were attracted to all nine yeasts studied. The behavioral response to baker's yeast was independent of its growth stage. In addition to Drosophila, we tested the basal hexapod Folsomia candida (Collembola) in a Y-tube assay to the most ancient yeast, Y. lipolytica, which proved that early yeast signals also function on clades older than neopteran insects. Behavioral and chemical data and a search for selected genes of volatile metabolites underline that biosynthesis of chemical signals is found throughout the yeast clade and has been conserved during the evolution of yeast lifestyles. Literature and database reviews corroborate that yeast signals mediate mutualistic interactions between insects and yeasts. Moreover, volatiles emitted by yeasts are commonly found also in flowers and attract many insect species. The collective evidence suggests that the release of volatile signals by yeasts is a widespread and phylogenetically ancient trait, and that insect-yeast communication evolved prior to the emergence of flowering plants. Co-occurrence of the same attractant signals in yeast and flowers suggests that yeast-insect communication may have contributed to the evolution of insect-mediated pollination in flowers.
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| 12. |
- Becher, Paul G., et al.
(författare)
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Developmentally regulated volatiles geosmin and 2-methylisoborneol attract a soil arthropod to Streptomyces bacteria promoting spore dispersal
- 2020
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Ingår i: Nature Microbiology. - : Springer Science and Business Media LLC. - 2058-5276.
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Tidskriftsartikel (refereegranskat)abstract
- Volatile compounds emitted by bacteria are often sensed by other organisms as odours, but their ecological roles are poorly understood1,2. Well-known examples are the soil-smelling terpenoids geosmin and 2-methylisoborneol (2-MIB)3,4, which humans and various animals sense at extremely low concentrations5,6. The conservation of geosmin biosynthesis genes among virtually all species of Streptomyces bacteria (and genes for the biosynthesis of 2-MIB in about 50%)7,8, suggests that the volatiles provide a selective advantage for these soil microbes. We show, in the present study, that these volatiles mediate interactions of apparent mutual benefit between streptomycetes and springtails (Collembola). In field experiments, springtails were attracted to odours emitted by Streptomyces colonies. Geosmin and 2-MIB in these odours induce electrophysiological responses in the antennae of the model springtail Folsomia candida, which is also attracted to both compounds. Moreover, the genes for geosmin and 2-MIB synthases are under the direct control of sporulation-specific transcription factors, constraining emission of the odorants to sporulating colonies. F. candida feeds on the Streptomyces colonies and disseminates spores both via faecal pellets and through adherence to its hydrophobic cuticle. The results indicate that geosmin and 2-MIB production is an integral part of the sporulation process, completing the Streptomyces life cycle by facilitating dispersal of spores by soil arthropods.
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| 13. |
- Becher, Paul, et al.
(författare)
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Infection of Drosophila suzukii with the obligate insect-pathogenic fungus Entomophthora muscae
- 2018
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Ingår i: Journal of Pest Science. - : Springer Science and Business Media LLC. - 1612-4758 .- 1612-4766. ; 91, s. 781-787
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Tidskriftsartikel (refereegranskat)abstract
- Physiological constraints restrict specialist pathogens from infecting new hosts. From an applied perspective, a narrow host range makes specialist pathogens interesting for targeting specific pest insects since they have minimal direct effects on non-target species. Entomopathogenic fungi of the genus Entomophthora are dipteran-specific but have not been investigated for their ability to infect the spotted wing drosophila (SWD; Drosophila suzukii) a fruit-damaging pest invasive to Europe and America. Our main goal was to study whether SWD is in the physiological host range of the entomophthoralean species E. muscae. We investigated pathogenicity and virulence of E. muscae towards its main natural host, the housefly Musca domestica, and towards SWD. We found that E. muscae readily infected and significantly reduced survival of SWD by 27.3% with the majority of flies dying 4-8 days post-exposure. In comparison with SWD, infection of the natural host M. domestica resulted in an even higher mortality of 62.9% and larger conidial spores of E. muscae, reflecting the physiological constraints of the pathogen in the atypical host. We demonstrated that pathogens of the E. muscae species complex that typically have a narrow natural host range of one or few dipteran species are able to infect SWD, and we described a new method for in vivo transmission and infection of an entomophthoralean fungus to SWD.
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| 14. |
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| 15. |
- Becher, Paul
(författare)
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Microbiota-mediated competition between Drosophila species
- 2023
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Ingår i: Microbiome. - 2049-2618. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Background The influence of microbiota in ecological interactions, and in particular competition, is poorly known. We studied competition between two insect species, the invasive pest Drosophila suzukii and the model Drosophila melanogaster, whose larval ecological niches overlap in ripe, but not rotten, fruit.Results We discovered D. suzukii females prevent costly interspecific larval competition by avoiding oviposition on substrates previously visited by D. melanogaster. More precisely, D. melanogaster association with gut bacteria of the genus Lactobacillus triggered D. suzukii avoidance. However, D. suzukii avoidance behavior is condition-dependent, and D. suzukii females that themselves carry D. melanogaster bacteria stop avoiding sites visited by D. melanogaster. The adaptive significance of avoiding cues from the competitor's microbiota was revealed by experimentally reproducing in-fruit larval competition: reduced survival of D. suzukii larvae only occurred if the competitor had its normal microbiota.Conclusions This study establishes microbiotas as potent mediators of interspecific competition and reveals a central role for context-dependent behaviors under bacterial influence.
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| 16. |
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| 17. |
- Becher, Paul, et al.
(författare)
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The Scent of the Fly
- 2018
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Ingår i: Journal of Chemical Ecology. - : Springer Science and Business Media LLC. - 0098-0331 .- 1573-1561. ; 44:5, s. 431-435
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Tidskriftsartikel (refereegranskat)abstract
- (Z)-4-undecenal (Z4-11Al) is the volatile pheromone produced by females of the vinegar fly Drosophila melanogaster. Female flies emit Z4-11Al for species-specific communication and mate-finding. A sensory panel finds that synthetic Z4-11Al has a characteristic flavour, which can be perceived even at the small amounts produced by a single female fly. Since only females produce Z4-11Al, and not males, we can reliably distinguish between single D. melanogaster males and females, according to their scent. Females release Z4-11Al at 2.4 ng/h and we readily sense 1 ng synthetic Z4-11Al in a glass of wine (0.03 nmol/L), while a tenfold concentration is perceived as a loud off-flavour. This corroborates the observation that a glass of wine is spoilt by a single D. melanogaster fly falling into it, which we here show is caused by Z4-11Al. The biological role of Z4-11Al or structurally related aldehydes in humans and the basis for this semiochemical convergence remains yet unclear.
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| 18. |
- Becher, Paul, et al.
(författare)
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Yeast, not fruit volatiles mediate Drosophila melanogaster attraction, oviposition and development
- 2012
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Ingår i: Functional Ecology. - : Wiley. - 1365-2435 .- 0269-8463. ; 26:4, s. 822-828
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Tidskriftsartikel (refereegranskat)abstract
- 1.In nature, the fruit fly Drosophila melanogaster is attracted to fermenting fruit. Micro-organisms like Saccharomyces yeasts growing on fruit occupy a commonly overlooked trophic level between fruit and insects. Although the dietary quality of yeast is well established for D.melanogaster, the individual contribution of fruit and yeast on host finding and reproductive success has not been established. 2.Here, we show that baker's yeast Saccharomyces cerevisiae on its own is sufficient for fruit fly attraction, oviposition and larval development. In contrast, attraction and oviposition were significantly lower if non-fermented grape juice or growth media were used, and yeast-free grapes did not support larval development either. 3.Despite a strong preference for fermented substrates, moderate attraction to and oviposition on unfermented fruit might be adaptive in view of the fly's capacity to vector yeast. 4.Signals emitted by fruit were only of secondary importance because fermenting yeast without fruit induced the same fly behaviour as yeast fermenting on fruit. We identified a synthetic mimic of yeast odour, comprising ethanol, acetic acid, acetoin, 2-phenyl ethanol and 3-methyl-1-butanol, which was as attractive for the fly as fermenting grape juice or fermenting yeast minimal medium. 5.Yeast odours represent the critical signal to establish the flyfruityeast relationship. The traditional plantherbivore niche concept needs to be updated, to accommodate for the role of micro-organisms in insectplant interactions.
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| 19. |
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| 20. |
- Bengtsson, Marie, et al.
(författare)
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Flying the Fly: Long-range Flight Behavior of Drosophila melanogaster to Attractive Odors
- 2010
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Ingår i: Journal of Chemical Ecology. - : Springer Science and Business Media LLC. - 0098-0331 .- 1573-1561. ; 36, s. 599-607
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Tidskriftsartikel (refereegranskat)abstract
- The fruit fly, Drosophila melanogaster Meigen (Diptera: Drosophilidae), is a model for how animals sense, discriminate, and respond to chemical signals. However, with D. melanogaster our knowledge of the behavioral activity of olfactory receptor ligands has relied largely on close-range attraction, rather than on long-range orientation behavior. We developed a flight assay to relate chemosensory perception to behavior. Headspace volatiles from vinegar attracted 62% of assayed flies during a 15-min experimental period. Flies responded irrespective of age, sex, and mating state, provided they had been starved. To identify behaviorally relevant chemicals from vinegar, we compared the responses to vinegar and synthetic chemicals. Stimuli were applied by a piezoelectric sprayer at known and constant release rates. Re-vaporized methanol extracts of Super Q-trapped vinegar volatiles attracted as many flies as vinegar. The main volatile component of vinegar, acetic acid, elicited significant attraction as a single compound. Two other vinegar volatiles, 2-phenyl ethanol and acetoin, produced a synergistic effect when added to acetic acid. Geosmin, a microbiological off-flavor, diminished attraction to vinegar. This wind tunnel assay based on a conspicuous and unambiguous behavioral response provides the necessary resolution for the investigation of physiologically and ecologically relevant odors and will become an essential tool for the functional analysis of the D. melanogaster olfactory system
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| 21. |
- Bergman, Åke, et al.
(författare)
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Science and policy on endocrine disrupters must not be mixed : a reply to a "common sense" intervention by toxicology journal editors
- 2013
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Ingår i: Environmental Health. - : BioMed Central (BMC). - 1476-069X. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- The "common sense" intervention by toxicology journal editors regarding proposed European Union endocrine disrupter regulations ignores scientific evidence and well-established principles of chemical risk assessment. In this commentary, endocrine disrupter experts express their concerns about a recently published, and is in our considered opinion inaccurate and factually incorrect, editorial that has appeared in several journals in toxicology. Some of the shortcomings of the editorial are discussed in detail. We call for a better founded scientific debate which may help to overcome a polarisation of views detrimental to reaching a consensus about scientific foundations for endocrine disrupter regulation in the EU.
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| 22. |
- Bohman, Björn, et al.
(författare)
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Pathogenic fungus uses volatiles to entice male flies into fatal matings with infected female cadavers
- 2022
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Ingår i: ISME Journal. - : Springer Science and Business Media LLC. - 1751-7362 .- 1751-7370. ; 16, s. 2388-2397
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Tidskriftsartikel (refereegranskat)abstract
- To ensure dispersal, many parasites and pathogens behaviourally manipulate infected hosts. Other pathogens and certain insect-pollinated flowers use sexual mimicry and release deceptive mating signals. However, it is unusual for pathogens to rely on both behavioural host manipulation and sexual mimicry. Here, we show that the host-specific and behaviourally manipulating pathogenic fungus, Entomophthora muscae, generates a chemical blend of volatile sesquiterpenes and alters the profile of natural host cuticular hydrocarbons in infected female housefly (Musca domestica) cadavers. Healthy male houseflies respond to the fungal compounds and are enticed into mating with female cadavers. This is advantageous for the fungus as close proximity between host individuals leads to an increased probability of infection. The fungus exploits the willingness of male flies to mate and benefits from altering the behaviour of uninfected male host flies. The altered cuticular hydrocarbons and emitted volatiles thus underlie the evolution of an extended phenotypic trait.
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| 23. |
- Borrero, Felipe, et al.
(författare)
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Flight attraction of Spodoptera littoralis (Lepidoptera, Noctuidae) to cotton headspace and synthetic volatile blends.
- 2015
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Ingår i: Frontiers in Ecology and Evolution. - : Frontiers Media SA. - 2296-701X. ; 3
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Tidskriftsartikel (refereegranskat)abstract
- The insect olfactory system discriminates odor signals of different biological relevance, which drive innate behavior. Identification of stimuli that trigger upwind flight attraction toward host plants is a current challenge, and is essential in developing new, sustainable plant protection methods, and for furthering our understanding of plant-insect interactions. Using behavioral, analytical and electrophysiological studies, we here show that both females and males of the Egyptian cotton leafworm,Spodoptera littoralis(Lepidoptera, Noctuidae), use blends of volatile compounds to locate their host plant, cotton,Gossypium hirsutum(Malvales, Malvaceae). FemaleS. littoraliswere engaged in upwind orientation flight in a wind tunnel when headspace collected from cotton plants was delivered through a piezoelectric sprayer. Although males took off toward cotton headspace significantly fewer males than females flew upwind toward the sprayed headspace. Subsequent assays with antennally active synthetic compounds revealed that a blend of nonanal, (Z)-3 hexenyl acetate, (E)-β-ocimene, and (R)-(+)-limonene was as attractive as cotton headspace to females and more attractive to males. Two compounds, 4,8-dimethyl-1,3(E),7-nonatriene (DMNT) and (R)-(−)-linalool, both known plant defense compounds may have reduced the flight attraction of both females and males; more moths were attracted to blends without these two compounds, however, other compounds such as benzaldehyde may also be behavioral antagonists. Our findings provide a platform for further investigations on host plant signals mediating innate behavior, and for the development of novel insect plant protection strategies againstS. littoralis.
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| 24. |
- Borrero, Felipe, et al.
(författare)
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The female sex pheromone (Z)-4-undecenal mediates flight attraction and courtship in Drosophila melanogaster
- 2022
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Ingår i: Journal of insect physiology. - : Elsevier BV. - 0022-1910 .- 1879-1611. ; 137
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Tidskriftsartikel (refereegranskat)abstract
- Specific mate communication and recognition underlies reproduction and hence speciation. Our study provides new insights in Drosophila melanogaster premating olfactory communication. Mate communication evolves during adaptation to ecological niches and makes use of social signals and habitat cues. Female-produced, species-specific volatile pheromone (Z)-4-undecenal (Z4-11Al) and male pheromone (Z)-11-octadecenyl acetate (cVA) interact with food odour in a sex-specific manner. Furthermore, Z4-11Al, which mediates upwind flight attraction in both sexes, also elicits courtship in experienced males. Two isoforms of the olfactory receptor Or69a are co-expressed in the same olfactory sensory neurons. Z4-11Al is perceived via Or69aB, while the food odorant (R)-linalool is a main ligand for the other variant, Or69aA. However, only Z4-11Al mediates courtship in experienced males, not (R)-linalool. Behavioural discrimination is reflected by calcium imaging of the antennal lobe, showing distinct glomerular activation patterns by these two compounds. Male sex pheromone cVA is known to affect male and female courtship at close range, but does not elicit upwind flight attraction as a single compound, in contrast to Z4-11Al. A blend of the food odour vinegar and cVA attracted females, while a blend of vinegar and female pheromone Z4-11Al attracted males, instead. Sex-specific upwind flight attraction to blends of food volatiles and male and female pheromone, respectively, adds a new element to Drosophila olfactory premating communication and is an unambiguous paradigm for identifying the behaviourally active components, towards a more complete concept of food-pheromone odour objects.
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| 25. |
- Carrasco, David, et al.
(författare)
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With or without you: Effects of the concurrent range expansion of an herbivore and its natural enemy on native species interactions
- 2018
-
Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 24, s. 631-643
-
Tidskriftsartikel (refereegranskat)abstract
- Global climatic changes may lead to the arrival of multiple range-expanding species from different trophic levels into new habitats, either simultaneously or in quick succession, potentially causing the introduction of manifold novel interactions into native food webs. Unraveling the complex biotic interactions between native and range-expanding species is critical to understand the impact of climate change on community ecology, but experimental evidence is lacking. In a series of laboratory experiments that simulated direct and indirect species interactions, we investigated the effects of the concurrent arrival of a range-expanding insect herbivore in Europe, Spodoptera littoralis, and its associated parasitoid Microplitis rufiventris, on the native herbivore Mamestra brassicae, and its associated parasitoid Microplitis mediator, when co-occurring on a native plant, Brassica rapa. Overall, direct interactions between the herbivores were beneficial for the exotic herbivore (higher pupal weight than the native herbivore), and negative for the native herbivore (higher mortality than the exotic herbivore). At the third trophic level, both parasitoids were unable to parasitize the herbivore they did not coexist with, but the presence of the exotic parasitoid still negatively affected the native herbivore (increased mortality) and the native parasitoid (decreased parasitism rate), through failed parasitism attempts and interference effects. Our results suggest different interaction scenarios depending on whether S. littoralis and its parasitoid arrive to the native tritrophic system separately or concurrently, as the negative effects associated with the presence of the parasitoid were dependent on the presence of the exotic herbivore. These findings illustrate the complexity and interconnectedness of multitrophic changes resulting from concurrent species arrival to new environments, and the need for integrating the ecological effects of such arrivals into the general theoretical framework of global invasion patterns driven by climatic change.
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| 26. |
- Chakraborty, Amrita, et al.
(författare)
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Yeast and fruit fly mutual niche construction and antagonism against mould
- 2022
-
Ingår i: Functional Ecology. - : Wiley. - 0269-8463 .- 1365-2435. ; 36:7, s. 1639-1654
-
Tidskriftsartikel (refereegranskat)abstract
- A goal in insect–microbe ecology is to understand the mechanisms regulating species associations and mutualistic interactions. The spotted wing drosophila Drosophila suzukii develops in ripening fruit, unlike other drosophilids that typically feed on overripe fruit, and is associated with the yeast Hanseniaspora uvarum. We hypothesized that D. suzukii and H. uvarum engage in niche construction leading to a mutualistic relation, facilitating the exploitation of fruit and berries as larval substrate. We show that H. uvarum proliferates on both ripe and on unripe raspberries, mediates attraction of D. suzukii larvae and adult flies, enhances egg-laying in mated females and is a sufficient food substrate to support larval development. Moreover, H. uvarum suppresses the antagonistic grey mould, Botrytis cinerea in collaboration with D. suzukii larvae, and produces less ethanol than baker's yeast. H. uvarum thus creates favourable conditions for D. suzukii larval development, which is susceptible to ethanol and grey mould. D. suzukii, on the other hand, vectors H. uvarum to suitable substrates such as raspberries, where larval feeding activity enhances growth of H. uvarum. Larval feeding also helps to suppress B. cinerea, which otherwise outcompetes H. uvarum on raspberry, in the absence of fly larvae. In conclusion, H. uvarum enhances D. suzukii larval development on unripe berries, and D. suzukii promotes H. uvarum dispersal and growth on berries. Yeast and fly modify their shared habitat in reciprocal niche construction and mutual interaction. Read the free Plain Language Summary for this article on the Journal blog.
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| 27. |
- Darlison, Julia, et al.
(författare)
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Leaf mineral content govern microbial community structure in the phyllosphere of spinach (Spinacia oleracea) and rocket (Diplotaxis tenuifolia)
- 2019
-
Ingår i: Science of the Total Environment. - : Elsevier BV. - 1879-1026 .- 0048-9697. ; 675, s. 501-512
-
Tidskriftsartikel (refereegranskat)abstract
- The plant microbiome is an important factor for plant health and productivity. While the impact of nitrogen (N) availability for plant growth and development is well established, its influence on the microbial phyllosphere community structure is unknown. We hypothesize that nitrogen impacts the growth and abundance of several microorganisms on the leaf surface. The bacterial and fungal communities of baby leaf spinach (Spinacia oleracea), and rocket (Diplotaxis tenuifolia) were investigated in a field trial for two years in a commercial setting. Nitrogen fertilizer was tested in four doses (basic nitrogen, basic + suboptimal, basic + commercial, basic + excess) with six replicates in each. Culture-independent (Illumina sequencing) and culture-dependent (viable count and identification of bacterial isolates) community studies were combined with monitoring of plant physiology and site weather conditions. This study found that alpha diversity of bacterial communities decreased in response to increasing nitrogen fertilizer dose, whereas viable counts showed no differences. Correspondingly, fungal communities of the spinach phyllosphere showed a decreasing pattern, whereas the decreasing diversity of fungal communities of rocket was not significant. Plant species and effects of annual variations on microbiome structure were observed for bacterial and fungal communities on both spinach and rocket. This study provides novel insights on the impact of nitrogen fertilizer regime on a nutrient scarce habitat, the phyllosphere.
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| 28. |
- Dekker, Teun, et al.
(författare)
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Loss of Drosophila pheromone reverses its role in sexual communication in Drosophila suzukii
- 2015
-
Ingår i: Proceedings of the Royal Society B: Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 282
-
Tidskriftsartikel (refereegranskat)abstract
- The Drosophila pheromone cis-11-octadecenyl acetate (cVA) is used as pheromone throughout the melanogaster group and fulfils a primary role in sexual and social behaviours. Here, we found that Drosophila suzukii, an invasive pest that oviposits in undamaged ripe fruit, does not produce cVA. In fact, its production site, the ejaculatory bulb, is atrophied. Despite loss of cVA production, its receptor, Or67d, and cognate sensillum, T1, which are essential in cVA-mediated behaviours, were fully functional. However, T1 expression was dramatically reduced in D. suzukii, and the corresponding antennal lobe glomerulus, DA1, minute. Behavioural responses to cVA depend on the input balance of Or67d neurons (driving cVA-mediated behaviours) and Or65a neurons (inhibiting cVA-mediated behaviours). Accordingly, the shifted input balance in D. suzukii has reversed cVA's role in sexual behaviour: perfuming D. suzukii males with Drosophila melanogaster equivalents of cVA strongly reduced mating rates. cVA has thus evolved from a generic sex pheromone to a heterospecific signal that disrupts mating in D. suzukii, a saltational shift, mediated through offsetting the input balance that is highly conserved in congeneric species. This study underlines that dramatic changes in a species' sensory preference can result from rather 'simple' numerical shifts in underlying neural circuits.
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| 29. |
- Dixon-Suen, Suzanne C, et al.
(författare)
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Physical activity, sedentary time and breast cancer risk : a Mendelian randomisation study
- 2022
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Ingår i: British Journal of Sports Medicine. - : BMJ Publishing Group Ltd. - 0306-3674 .- 1473-0480. ; 56:20, s. 1157-1170
-
Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: Physical inactivity and sedentary behaviour are associated with higher breast cancer risk in observational studies, but ascribing causality is difficult. Mendelian randomisation (MR) assesses causality by simulating randomised trial groups using genotype. We assessed whether lifelong physical activity or sedentary time, assessed using genotype, may be causally associated with breast cancer risk overall, pre/post-menopause, and by case-groups defined by tumour characteristics.METHODS: We performed two-sample inverse-variance-weighted MR using individual-level Breast Cancer Association Consortium case-control data from 130 957 European-ancestry women (69 838 invasive cases), and published UK Biobank data (n=91 105-377 234). Genetic instruments were single nucleotide polymorphisms (SNPs) associated in UK Biobank with wrist-worn accelerometer-measured overall physical activity (nsnps=5) or sedentary time (nsnps=6), or accelerometer-measured (nsnps=1) or self-reported (nsnps=5) vigorous physical activity.RESULTS: Greater genetically-predicted overall activity was associated with lower breast cancer overall risk (OR=0.59; 95% confidence interval (CI) 0.42 to 0.83 per-standard deviation (SD;~8 milligravities acceleration)) and for most case-groups. Genetically-predicted vigorous activity was associated with lower risk of pre/perimenopausal breast cancer (OR=0.62; 95% CI 0.45 to 0.87,≥3 vs. 0 self-reported days/week), with consistent estimates for most case-groups. Greater genetically-predicted sedentary time was associated with higher hormone-receptor-negative tumour risk (OR=1.77; 95% CI 1.07 to 2.92 per-SD (~7% time spent sedentary)), with elevated estimates for most case-groups. Results were robust to sensitivity analyses examining pleiotropy (including weighted-median-MR, MR-Egger).CONCLUSION: Our study provides strong evidence that greater overall physical activity, greater vigorous activity, and lower sedentary time are likely to reduce breast cancer risk. More widespread adoption of active lifestyles may reduce the burden from the most common cancer in women.
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| 30. |
- Erdei, Anna, et al.
(författare)
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Insect chemical ecology: chemically mediated interactions and novel applications in agriculture
- 2020
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Ingår i: Arthropod-Plant Interactions. - : Springer Science and Business Media LLC. - 1872-8855 .- 1872-8847. ; 14, s. 671-684
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Tidskriftsartikel (refereegranskat)abstract
- Insect chemical ecology (ICE) evolved as a discipline concerned with plant-insect interactions, and also with a strong focus on intraspecific pheromone-mediated communication. Progress in this field has rendered a more complete picture of how insects exploit chemical information in their surroundings in order to survive and navigate their world successfully. Simultaneously, this progress has prompted new research questions about the evolution of insect chemosensation and related ecological adaptations, molecular mechanisms that mediate commonly observed behaviors, and the consequences of chemically mediated interactions in different ecosystems. Themed meetings, workshops, and summer schools are ideal platforms for discussing scientific advancements as well as identifying gaps and challenges within the discipline. From the 11th to the 22nd of June 2018, the 11th annual PhD course in ICE was held at the Swedish University of Agricultural Sciences (SLU) Alnarp, Sweden. The course was made up of 35 student participants from 22 nationalities (Fig. 1a) as well as 32 lecturers. Lectures and laboratory demonstrations were supported by literature seminars, and four broad research areas were covered: (1) multitrophic interactions and plant defenses, (2) chemical communication focusing on odor sensing, processing, and behavior, (3) disease vectors, and (4) applied aspects of basic ICE research in agriculture. This particular article contains a summary and brief synthesis of these main emergent themes and discussions from the ICE 2018 course. In addition, we also provide suggestions on teaching the next generation of ICE scientists, especially during unprecedented global situations.
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| 31. |
- Farnier, Kevin, et al.
(författare)
-
Novel bioassay demonstrates attraction of the white potato cyst nematode Globodera pallida (Stone) to non-volatile and volatile host plant cues
- 2012
-
Ingår i: Journal of Chemical Ecology. - : Springer. - 0098-0331 .- 1573-1561. ; 38:6, s. 795-801
-
Tidskriftsartikel (refereegranskat)abstract
- Potato cyst nematodes (PCNs) are a major pest of solanaceous crops such as potatoes, tomatoes, and eggplants and have been widely studied over the last 30 years, with the majority of earlier studies focusing on the identification of natural hatching factors. As a novel approach, we focused instead on chemicals involved in nematode orientation towards its host plant. A new dual choice sand bioassay was designed to study nematode responses to potato root exudates (PRE). This bioassay, conducted together with a traditional hatching bioassay, showed that biologically active compounds that induce both hatching and attraction of PCNs can be collected by water extraction of incised potato roots. Furthermore, our results demonstrated that PCN also were attracted by potato root volatiles. Further work is needed to fully understand how PCNs use host plant chemical cues to orientate towards hosts. Nevertheless, the simple attraction assay used in this study provides an important tool for the identification of host-emitted attractants.
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| 32. |
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| 33. |
- Frey, T., et al.
(författare)
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The human odorant receptor OR10A6 is tuned to the pheromone of the commensal fruit fly Drosophila melanogaster
- 2022
-
Ingår i: iScience. - : Elsevier BV. - 2589-0042. ; 25:11
-
Tidskriftsartikel (refereegranskat)abstract
- All living things speak chemistry. The challenge is to reveal the vocabulary, the odorants that enable communication across phylogenies and to translate them to physiological, behavioral, and ecological function. Olfactory receptors (ORs) interface animals with airborne odorants. Expression in heterologous cells makes it possible to interrogate single ORs and to identify cognate ligands. The cosmopolitan, anthropophilic strain of the vinegar fly Drosophila melanogaster depends on human resources and housing for survival. Curiously, humans sense the pheromone (Z)-4-undecenal (Z4-11Al) released by single fly females. A screening of all human ORs shows that the most highly expressed OR10A6 is tuned to Z4-11Al. Females of an ancestral African fly strain release a blend of Z4-11Al and Z4-9Al that produces a different aroma, which is how we distinguish these fly strains by nose. That flies and humans sense Z4-11Al via dedicated ORs shows how convergent evolution shapes communication channels between vertebrate and invertebrate animals.
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| 34. |
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| 35. |
- Jung, Audrey Y, et al.
(författare)
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Distinct reproductive risk profiles for intrinsic-like breast cancer subtypes : pooled analysis of population-based studies
- 2022
-
Ingår i: Journal of the National Cancer Institute. - : Oxford University Press. - 0027-8874 .- 1460-2105. ; 114:12, s. 1706-1719
-
Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Reproductive factors have been shown to be differentially associated with risk of estrogen receptor (ER) positive and ER-negative breast cancer. However, their associations with intrinsic-like subtypes are less clear.METHODS: Analyses included up to 23,353 cases, and 71,072 controls pooled from 31 population-based case-control or cohort studies in the Breast Cancer Association Consortium across 16 countries on 4 continents. Polytomous logistic regression was used to estimate the association between reproductive factors and risk of breast cancer by intrinsic-like subtypes (luminal A-like, luminal B-like, luminal B-HER2-like, HER2-enriched-like, and triple-negative) and by invasiveness. All statistical tests were 2-sided.RESULTS: Compared to nulliparous women, parous women had a lower risk of luminal A-like, luminal B-like, luminal B-HER2-like and HER2-enriched-like disease. This association was apparent only after approximately 10 years since last birth and became stronger with increasing time (odds ratio [OR] = 0.59, 95% confidence interval [CI] = 0.49 to 0.71; and OR = 0.36, 95% CI = 0.28 to 0.46; for multiparous women with luminal A-like tumors 20-<25 years after last birth and 45-<50 years after last birth, respectively). In contrast, parous women had a higher risk of triple-negative breast cancer right after their last birth (for multiparous women: OR = 3.12, 95%CI = 2.02 to 4.83) that was attenuated with time but persisted for decades (OR = 1.03, 95%CI = 0.79 to 1.34, for multiparous women 25 to < 30 years after last birth). Older age at first birth (P-heterogeneity<.001 for triple-negative compared to luminal-A like) and breastfeeding (P-heterogeneity<.001 for triple-negative compared to luminal-A like) were associated with lower risk of triple-negative but not with other disease subtypes. Younger age at menarche was associated with higher risk of all subtypes; older age at menopause was associated with higher risk of luminal A-like but not triple-negative breast cancer. Associations for in situ tumors were similar to luminal A-like.CONCLUSION: This large and comprehensive study demonstrates a distinct reproductive risk factor profile for triple-negative breast cancer compared to other subtypes, with implications for the understanding of disease etiology and risk prediction.
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| 36. |
- Kautto, Arja H, et al.
(författare)
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Pestivirus and alphaherpesvirus infections in Swedish reindeer (Rangifer tarandus tarandus L.)
- 2012
-
Ingår i: Veterinary Microbiology. - : Elsevier. - 0378-1135 .- 1873-2542. ; 156:1-2, s. 64-71
-
Tidskriftsartikel (refereegranskat)abstract
- Herding semi-domesticated reindeer has economic and social value for Sami people in the northern territories of Fennoscandia. However, with the intensification of reindeer husbandry, interspecies transmission of pathogens between reindeer and domestic animals may become a problem, especially for countries such as Sweden, Norway, and Finland where pestivirus and alphaherpesvirus have been eradicated in domestic ruminants. This study, which included 1158 Swedish reindeer, showed relatively high prevalence of antibodies against bovine viral diarrhoea virus (BVDV) (32%) and bovine herpesvirus-1 (BoHV-1) (53%). Adult animals were more often seropositive for BVDV and BoHV-1 (50% and 78%, respectively) than were calves (18 and 11%, respectively). While the seroprevalence of alphaherpesvirus was similar in different herding districts, pestivirus seropositivity was highest in the South and diminished towards the North of the Swedish reindeer herding area. High correlation of the seropositivity against both pathogens at both individual and herd levels may indicate possible mutual synergetic effects and may be explained by the immunosuppressive nature of the viruses. While alphaherpesvirus seroprevalence was probably related to putative cervid herpesvirus 2 (CvHV-2), the pestivirus infecting reindeer remains undefined. The virus neutralisation test of reindeer sera using different pestivirus strains, revealed higher titres against Border disease virus strains like 137/4 (BDV-1) and Reindeer-1 (BDV-2) than against BVDV-1. However, the virus was not identified by real time RT-PCR in any of the samples (n=276) from seronegative reindeers. The study showed that pestivirus and alphaherpesvirus infections are endemic in the Swedish reindeer population.
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| 37. |
- Kleman, Isabella, et al.
(författare)
-
Hanseniaspora uvarum Attracts Drosophila suzukii (Diptera: Drosophilidae) With High Specificity
- 2022
-
Ingår i: Journal of Economic Entomology. - : Oxford University Press (OUP). - 0022-0493 .- 1938-291X. ; 115, s. 999-1007
-
Tidskriftsartikel (refereegranskat)abstract
- Since the early phase of the intercontinental dispersal of Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), fermentation baits have been used for monitoring. Self-made lures and commercial products are often based on wine and vinegar. From an ecological perspective, the formulation of these baits is expected to target especially vinegar flies associated with overripe fruit, such as Drosophila melanogaster (Meigen) (Diptera: Drosophilidae). Hanseniaspora uvarum (Niehaus) (Ascomycota: Saccharomyceta) is a yeast closely associated with D. suzukii and fruit, and furthermore attractive to the flies. Based on this relation, H. uvarum might represent a suitable substrate for the development of lures that are more specific than vinegar and wine. In the field, we therefore, compared H. uvarum to a commercial bait that was based on vinegar and wine with respect to the number of trapped D. suzukii relative to other drosophilids and arthropods. Trap captures were higher with the commercial bait but specificity for D. suzukii was greater with H. uvarum. Moreover, H. uvarum headspace extracts, as well as a synthetic blend of H. uvarum volatiles, were assayed for attraction of D suzukii in a wind tunnel and in the field. Headspace extracts and the synthetic blend induced strong upwind flight in the wind tunnel and confirmed attraction to H. uvarum volatiles. Furthermore, baited with H. uvarum headspace extract and a drowning solution of aqueous acetic acid and ethanol, 74% of field captured arthropods were D. suzukii. Our findings suggest that synthetic yeast headspace formulations might advance the development of more selective monitoring traps with reduced by-catch.
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| 38. |
- Kleman, Isabella, et al.
(författare)
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Jästbaserat lockbete för prognos och bekämpning av Drosophila suzukii
- 2022
-
Ingår i: LTV-fakultetens faktablad.
-
Annan publikation (populärvet., debatt m.m.)abstract
- Den invasiva fruktflugan Drosophila suzukii är en allvarlig skadegörare på mjukskaliga frukter och bär. Bekämpningen av flugan är komplicerad och kräver en kombination av förebyggande och direkta åtgärder. Övervakning är ett nyckelelement i bekämpningen av D. suzukii, men traditionell fällfångst ger problem i form av stor bifångst av fel sorts insekter. Baserat på den mutualistiska relation som finns mellan D. suzukii och jästsvampen Hanseniaspora uvarum undersökte vi möjligheten att använda denna jästart för att utveckla lockbeten för flugan.
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| 39. |
- Kleman, Isabella, et al.
(författare)
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Simple quality prediction measurements for stored onions
- 2023
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Ingår i: Acta Horticulturae. - 0567-7572 .- 2406-6168. ; , s. 183-186
-
Konferensbidrag (refereegranskat)abstract
- Onion (Allium cepa) is an important crop that is cultivated and consumed all over the world. It is the second most produced horticultural vegetable crop (after tomato) based on weight. In order to be available year-round in Sweden, onions must be stored for several months during the cold part of the year, when no fresh onions can be harvested. However, dormancy break resulting in early sprouting is a common quality problem during storage. Before visible sprouting, changes in the bulb chemical composition takes place, including relocation of oligosaccharides and breakdown of larger sugar molecules into smaller units that are then used as energy during the sprouting process. In this project we used a hand-held reflectometer to measure levels of mono- and disaccharides and calcium in onion bulbs that had been stored for different time periods in order to evaluate the usefulness of the method for quality control. Measured contents of glucose and calcium changed significantly during storage while sucrose content remained relatively unchanged.
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| 40. |
- Kromann, Sophie, et al.
(författare)
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Concurrent modulation of neuronal and behavioural olfactory responses to sex and host plant cues in a male moth
- 2015
-
Ingår i: Proceedings of the Royal Society B: Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 282
-
Tidskriftsartikel (refereegranskat)abstract
- Mating has profound effects on animal physiology and behaviour, not only in females but also in males, which we show here for olfactory responses. In cotton leafworm moths, Spodoptera littoralis, odour-mediated attraction to sex pheromone and plant volatiles are modulated after mating, producing a behavioural response that matches the physiological condition of the male insect. Unmated males are attracted by upwind flight to sex pheromone released by calling females, as well as to volatiles of lilac flowers and green leaves of the host plant cotton, signalling adult food and mating sites, respectively. Mating temporarily abolishes male attraction to females and host plant odour, but does not diminish attraction to flowers. This behavioural modulation is correlated with a response modulation in the olfactory system, as shown by electro-physiological recordings from antennae and by functional imaging of the antennal lobe, using natural odours and synthetic compounds. An effect of mating on the olfactory responses to pheromone and cotton plant volatiles but not to lilac flowers indicates the presence of functionally independent neural circuits within the olfactory system. Our results indicate that these circuits interconnect and weigh perception of social and habitat odour signals to generate appropriate behavioural responses according to mating state.
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| 41. |
- Kwadha, Charles, et al.
(författare)
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Detection of the spotted wing drosophila, Drosophila suzukii, in continental sub-Saharan Africa
- 2021
-
Ingår i: Journal of Pest Science. - : Springer Science and Business Media LLC. - 1612-4758 .- 1612-4766. ; 94, s. 251-259
-
Tidskriftsartikel (refereegranskat)abstract
- The spotted wing drosophila, Drosophila suzukii Matsumura, is an insect pest of soft-skinned fruit, native to Eastern Asia. Since 2008, a world-wide dispersal of D. suzukii is seen, characterized by the establishment of the pest in many Asian, American and European countries. While the potential for invasion of continental Africa by D. suzukii has been predicted, its presence has only been shown for Morocco in Northern Africa. Knowledge about a possible establishment in other parts of the continent is needed as a basis for pest management. In 2019, we carried out a first survey in three counties in Kenya to monitor for the presence of D. suzukii using traps baited with a blend of apple cider vinegar and red wine. A total of 389 D. suzukii flies were captured in a fruit farm at Nakuru county, with more female flies being trapped than males. We confirmed the morphological identification of D. suzukii using DNA barcoding. In 2020, we performed a follow-up survey at 14 locations in six counties to delimit the distribution of D. suzukii in the main berry growing zones in Kenya. The survey indicated that so far D. suzukii is restricted to Nakuru county where it was initially detected. This is the first study to provide empirical evidence of D. suzukii in continental sub-Saharan Africa, confirming that the pest is expanding its geographic range intercontinentally. Given the high dispersal potential of D. suzukii, a concerted effort to develop management strategies is a necessity for containment of the pest.
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| 42. |
- Lebreton, Sebastien, et al.
(författare)
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A Drosophila female pheromone elicits species-specific long-range attraction via an olfactory channel with dual specificity for sex and food
- 2017
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Ingår i: BMC Biology. - : Springer Science and Business Media LLC. - 1741-7007. ; 15:1
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Mate finding and recognition in animals evolves during niche adaptation and involves social signals and habitat cues. Drosophila melanogaster and related species are known to be attracted to fermenting fruit for feeding and egg-laying, which poses the question of whether species-specific fly odours contribute to long-range premating communication. Results: We have discovered an olfactory channel in D. melanogaster with a dual affinity to sex and food odorants. Female flies release a pheromone, (Z)-4-undecenal (Z4-11Al), that elicits flight attraction in both sexes. Its biosynthetic precursor is the cuticular hydrocarbon (Z,Z)-7,11-heptacosadiene (7,11-HD), which is known to afford reproductive isolation between the sibling species D. melanogaster and D. simulans during courtship. Twin olfactory receptors, Or69aB and Or69aA, are tuned to Z4-11Al and food odorants, respectively. They are co-expressed in the same olfactory sensory neurons, and feed into a neural circuit mediating species-specific, long-range communication; however, the close relative D. simulans, which shares food resources with D. melanogaster, does not respond to Z4-11Al. Conclusion: The Or69aA and Or69aB isoforms have adopted dual olfactory traits. The underlying gene yields a collaboration between natural and sexual selection, which has the potential to drive speciation.
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| 43. |
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| 44. |
- Lebreton, Sebastien, et al.
(författare)
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Dietary glucose regulates yeast consumption in adult Drosophila males
- 2014
-
Ingår i: Frontiers in Physiology. - : Frontiers Media SA. - 1664-042X. ; 5
-
Tidskriftsartikel (refereegranskat)abstract
- The adjustment of feeding behavior in response to hunger and satiety contributes to homeostatic regulation in animals. The fruit fly Drosophila melanogaster feeds on yeasts growing on overripe fruit, providing nutrients required for adult survival, reproduction and larval growth. Here, we present data on how the nutritional value of food affects subsequent yeast consumption in Drosophila adult males. After a period of starvation, flies showed intensive yeast consumption. In comparison, flies stopped feeding after having access to a nutritive cornmeal diet. Interestingly, dietary glucose was equally efficient as the complex cornmeal diet. In contrast, flies fed with sucralose, a non-metabolizable sweetener, behaved as if they were starved. The adipokinetic hormone and insulin-like peptides regulate metabolic processes in insects. We did not find any effect of the adipokinetic hormone pathway on this modulation. Instead, the insulin pathway was involved in these changes. Flies lacking the insulin receptor (InR) did not respond to nutrient deprivation by increasing yeast consumption. Together these results show the importance of insulin in the regulation of yeast consumption in response to starvation in adult D. melanogaster males.
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| 45. |
- Lebreton, Sebastien, et al.
(författare)
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Feeding regulates sex pheromone attraction and courtship in Drosophila females
- 2015
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- In Drosophila melanogaster, gender-specific behavioural responses to the male-produced sex pheromone cis-vaccenyl acetate (cVA) rely on sexually dimorphic, third-order neural circuits. We show that nutritional state in female flies modulates cVA perception in first-order olfactory neurons. Starvation increases, and feeding reduces attraction to food odour, in both sexes. Adding cVA to food odour, however, maintains attraction in fed females, while it has no effect in males. Upregulation of sensitivity and behavioural responsiveness to cVA in fed females is paralleled by a strong increase in receptivity to male courtship. Functional imaging of the antennal lobe (AL), the olfactory centre in the insect brain, shows that olfactory input to DA1 and VM2 glomeruli is also modulated by starvation. Knocking down insulin receptors in neurons converging onto the DA1 glomerulus suggests that insulin-signalling partly controls pheromone perception in the AL, and adjusts cVA attraction according to nutritional state and sexual receptivity in Drosophila females.
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| 46. |
- Lebreton, Sebastien, et al.
(författare)
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Love makes smell blind: mating suppresses pheromone attraction in Drosophila females via Or65a olfactory neurons
- 2014
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 4, s. 1-6
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Tidskriftsartikel (refereegranskat)abstract
- In Drosophila, the male sex pheromone cis-vaccenyl acetate (cVA) elicits aggregation and courtship, through the odorant receptor Or67d. Long-lasting exposure to cVA suppresses male courtship, via a second channel, Or65a. In females, the role of Or65a has not been studied. We show that, shortly after mating, Drosophila females are no longer attracted to cVA and that activation of olfactory sensory neurons (OSNs) expressing Or65a generates this behavioral switch: when silencing Or65a, mated females remain responsive to cVA. Neurons expressing Or67d converge into the DA1 glomerulus in the antennal lobe, where they synapse onto projection neurons (PNs), that connect to higher neural circuits generating the attraction response to cVA. Functional imaging of these PNs shows that the DA1 glomerulus is inhibited by simultaneous activation of Or65a OSNs, which leads to a suppression of the attraction response to cVA. The behavioral role of postmating cVA exposure is substantiated by the observation that matings with starved males, which produce less cVA, do not alter the female response. Moreover, exposure to synthetic cVA abolishes attraction and decreases sexual receptivity in unmated females. Taken together, Or65a mediates an aversive effect of cVA and may accordingly regulate remating, through concurrent behavioral modulation in males and females.
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| 47. |
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| 48. |
- Mansourian, Suzan, et al.
(författare)
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Wild African Drosophila melanogaster are seasonal specialists on marula fruits
- 2018
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Ingår i: Current Biology. - 1879-0445. ; 28:24, s. 3-3968
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Tidskriftsartikel (refereegranskat)abstract
- Although the vinegar fly Drosophila melanogaster isarguably the most studied organism on the planet,fundamental aspects of this species’ natural ecologyhave remained enigmatic [1]. We have here investigateda wild population of D. melanogaster from amopane forest in Zimbabwe. We find that these fliesare closely associated with marula fruit (Sclerocaryabirrea) and propose that this seasonally abundantand predominantly Southern African fruit is a keyancestral host of D. melanogaster. Moreover, whenfruiting, marula is nearly exclusively used byD. melanogaster, suggesting that these forest-dwellingD. melanogaster are seasonal specialists, in asimilar manner to, e.g., Drosophila erecta on screwpine cones [2]. We further demonstrate that themain chemicals released by marula activate odorantreceptors that mediate species-specific host choice(Or22a) [3, 4] and oviposition site selection (Or19a)[5]. The Or22a-expressing neurons—ab3A—respondstrongly to the marula ester ethyl isovalerate, a volatilerarely encountered in high amounts in other fruit.We also show that Or22a differs among African populationssampled from a wide range of habitats, inline with a function associated with host fruit usage.Flies from Southern Africa, most of which carry adistinct allele at the Or22a/Or22b locus, have ab3Aneurons that are more sensitive to ethyl isovaleratethan, e.g., European flies. Finally, we discuss thepossibility that marula, which is also a culturallyand nutritionally important resource to humans,may have helped the transition to commensalism inD. melanogaster.
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| 49. |
- Mori, Boyd, et al.
(författare)
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Enhanced yeast feeding following mating facilitates control of the invasive fruit pest Drosophila suzukii
- 2017
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Ingår i: Journal of Applied Ecology. - : Wiley. - 0021-8901 .- 1365-2664. ; 54, s. 170-177
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Tidskriftsartikel (refereegranskat)abstract
- The highly invasive spotted wing Drosophila Drosophila suzukii is a key pest of soft fruit and berries in Europe and North America, and development of control techniques is an urgent research challenge. Drosophila suzukii is widely associated with the yeast Hanseniaspora uvarum. Yeasts are symbionts of drosophilid flies and communicate with insects through volatile metabolites for spore dispersal. Accordingly, yeasts and behaviour-modifying chemicals produced by yeasts are prospective tools for environmentally sound insect management. We first bioassayed flight attraction, feeding and oviposition of D.suzukii females in response to H.uvarum yeast and blueberries, which are a preferred host fruit. We then investigated the combined effect of yeast and insecticide on adult female oviposition behaviour and mortality towards the development of a yeast-based control method. Following mating, attraction of female flies to blueberry and yeast odour cues was strongly enhanced. Yeast feeding significantly increased in mated females, while yeast did not increase oviposition on blueberries. This observation suggests that mated flies become attracted to yeast for feeding and to fruit for egg laying. A combined feeding-oviposition assay demonstrated different roles and interference between yeast and fruit stimuli: during the day after mating, females laid fewer eggs when yeast was available. The post-mating yeast-feeding response is an opportunity for the development of an attract-and-kill technique for population control of D.suzukii. Exposing flies to a blend of yeast and insecticide reduced oviposition and greatly enhanced adult fly mortality compared with an insecticide treatment alone.Synthesis and applications. Mated females are the key life stage for Drosophila suzukii population control. Egg-laying females perforate fruit skin and fungal infestations ensue, even when eggs and larvae are killed off by insecticide sprays. Behaviour-modifying chemicals, including yeast metabolites, enable environmentally safe insect management via manipulation of olfactory-mediated reproductive behaviour. Our results highlight that yeast and yeast semiochemicals hold potential for D.suzukii management and that response modulation to olfactory stimuli following mating is a vital element for the development of D.suzukii control methods. Yeast feeding is enhanced in mated D.suzukii females, and this change in post-mating behaviour can be exploited by an attract-and-kill strategy, combining a fly-associated yeast with an insecticide. Furthermore, using the D.suzukii yeast mutualist, H.uvarum, may reduce non-target effects and increase species specificity, which further contributes to the development of an efficient and safe control method.
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| 50. |
- Rehermann Del Rio, Guillermo, et al.
(författare)
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Behavioral manipulation of Drosophila suzukii for pest control: high attraction to yeast enhances insecticide efficacy when applied on leaves
- 2022
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Ingår i: Pest Management Science. - : Wiley. - 1526-498X .- 1526-4998. ; 78, s. 896-904
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND The invasive pest, Drosophila suzukii attacks fresh soft-skinned fruit. Broad-spectrum insecticides are implemented for control but there is a need to reduce environmental risks and insecticide residues on fruits. Hanseniaspora uvarum is a yeast frequently found on ripe fruits and associated with D. suzukii. We aim to exploit the ecological association and attraction of D. suzukii to H. uvarum by developing an attract-and-kill strategy, with spray-application on canopy but not fruit. We therefore investigated D. suzukii attraction, egg-laying and mortality when exposed to insecticidal yeast-based formulations. RESULTS Hanseniaspora uvarum strongly attracted D. suzukii when applied on leaves of grapevine, Vitis vinifera. Notably, this attractiveness was competitive to ripe grape berries that were susceptible to D. suzukii infestation. Moreover, adding H. uvarum enhanced the efficacy of insecticidal formulations against D. suzukii. Flies exposed to leaves treated with yeast-insecticide formulations showed higher mortality and laid a lower number of eggs compared to flies exposed to insecticide alone. In a wind tunnel, all treatments containing H. uvarum alone or in combination with insecticides, caused similar upwind flight and landing at the odor source, which provides evidence that the addition of insecticide did not reduce D. suzukii attraction to yeast. CONCLUSION Hanseniaspora uvarum can be used to manipulate the behavior of D. suzukii by attracting flies to insecticide formulations. Yeast attraction is competitive to grape berries and improves insecticide effectiveness, suggesting that sprays covering canopy only, could reduce residues on fruit without compromising management efficacy.
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