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Takken W, Charlwood D, Lindsay SW. The behaviour of adult Anopheles gambiae, sub-Saharan Africa's principal malaria vector, and its relevance to malaria control: a review. Malar J 2024; 23:161. [PMID: 38783348 PMCID: PMC11112813 DOI: 10.1186/s12936-024-04982-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 05/11/2024] [Indexed: 05/25/2024] Open
Abstract
BACKGROUND Mosquitoes of the Anopheles gambiae complex are one of the major vectors of malaria in sub-Saharan Africa. Their ability to transmit this disease of major public health importance is dependent on their abundance, biting behaviour, susceptibility and their ability to survive long enough to transmit malaria parasites. A deeper understanding of this behaviour can be exploited for improving vector surveillance and malaria control. FINDINGS Adult mosquitoes emerge from aquatic habitats at dusk. After a 24 h teneral period, in which the cuticle hardens and the adult matures, they may disperse at random and search upwind for a mate or to feed. Mating generally takes place at dusk in swarms that form over species-specific 'markers'. Well-nourished females may mate before blood-feeding, but the reverse is true for poorly-nourished insects. Females are monogamous and only mate once whilst males, that only feed on nectar, swarm nightly and can potentially mate up to four times. Females are able to locate hosts by following their carbon dioxide and odour gradients. When in close proximity to the host, visual cues, temperature and relative humidity are also used. Most blood-feeding occurs at night, indoors, with mosquitoes entering houses mainly through gaps between the roof and the walls. With the exception of the first feed, females are gonotrophically concordant and a blood meal gives rise to a complete egg batch. Egg development takes two or three days depending on temperature. Gravid females leave their resting sites at dusk. They are attracted by water gradients and volatile chemicals that provide a suitable aquatic habitat in which to lay their eggs. CONCLUSION Whilst traditional interventions, using insecticides, target mosquitoes indoors, additional protection can be achieved using spatial repellents outdoors, attractant traps or house modifications to prevent mosquito entry. Future research on the variability of species-specific behaviour, movement of mosquitoes across the landscape, the importance of light and vision, reproductive barriers to gene flow, male mosquito behaviour and evolutionary changes in mosquito behaviour could lead to an improvement in malaria surveillance and better methods of control reducing the current over-reliance on the indoor application of insecticides.
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Affiliation(s)
- Willem Takken
- Laboratory of Entomology, Wageningen University & Research, PO Box 16, 6700 AA, Wageningen, The Netherlands.
| | - Derek Charlwood
- Global Health and Tropical Medicine, Instituto de Hygiene e Medicina Tropical, Lisbon, Portugal
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2
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Bezerra-Santos MA, Benelli G, Germinara GS, Volf P, Otranto D. Smelly interactions: host-borne volatile organic compounds triggering behavioural responses in mosquitoes, sand flies, and ticks. Parasit Vectors 2024; 17:227. [PMID: 38755646 PMCID: PMC11100076 DOI: 10.1186/s13071-024-06299-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Accepted: 04/23/2024] [Indexed: 05/18/2024] Open
Abstract
Volatile organic compounds (VOCs) are chemicals emitted as products of cell metabolism, which reflects the physiological and pathological conditions of any living organisms. These compounds play a key role as olfactory cues for arthropod vectors such as mosquitoes, sand flies, and ticks, which act in the transmission of pathogens to many animal species, including humans. Some VOCs may influence arthropod behaviour, e.g., host preference and oviposition site selection for gravid females. Furthermore, deadly vector-borne pathogens such as Plasmodium falciparum and Leishmania infantum are suggested to manipulate the VOCs profile of the host to make them more attractive to mosquitoes and sand fly vectors, respectively. Under the above circumstances, studies on these compounds have demonstrated their potential usefulness for investigating the behavioural response of mosquitoes, sand flies, and ticks toward their vertebrate hosts, as well as potential tools for diagnosis of vector-borne diseases (VBDs). Herein, we provide an account for scientific data available on VOCs to study the host seeking behaviour of arthropod vectors, and their usefulness as attractants, repellents, or tools for an early diagnosis of VBDs.
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Affiliation(s)
| | - Giovanni Benelli
- Department of Agriculture, Food and Environment, University of Pisa, Pisa, Italy
| | | | - Petr Volf
- Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Domenico Otranto
- Department of Veterinary Medicine, University of Bari, Bari, Italy.
- Department of Veterinary Clinical Sciences, City University of Hong Kong, Hong Kong, China.
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3
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Khan Z, Bohman B, Ignell R, Hill SR. Odour-mediated oviposition site selection in Aedes aegypti depends on aquatic stage and density. Parasit Vectors 2023; 16:264. [PMID: 37542293 PMCID: PMC10403918 DOI: 10.1186/s13071-023-05867-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 07/04/2023] [Indexed: 08/06/2023] Open
Abstract
BACKGROUND Olfaction plays an important role in the selection and assessment of oviposition sites by mosquitoes. Volatile organic compounds (VOCs) associated with potential breeding sites affect the behaviour of gravid mosquitoes, with VOCs from aquatic stages of conspecific mosquitoes influencing and regulating oviposition. The purpose of this study was to conduct a systematic analysis of the behavioural response of gravid Aedes aegypti to conspecific aquatic stage-conditioned water, to identify the associated bioactive VOCs and to determine how blends of these VOCs regulate oviposition site selection and stimulate egg-laying. METHODS Using a multi-choice olfactory oviposition assay, controlling for other sensory modalities, the responses of individual females to water conditioned with different densities of conspecific aquatic stages were assessed. The conditioned water samples from the most preferred density of each aquatic stage were subsequently compared to each other using the same oviposition assay and analysed using an analysis of variance (ANOVA) followed by a Tukey post-hoc test. Using combined gas chromatography and electroantennographic detection or mass spectrometry, bioactive VOCs from the preferred density of each aquatic stage were identified. Synthetic blends were prepared based on the identified ratios of bioactive VOCs in the aquatic stages, and then tested to determine the oviposition choice of Ae. aegypti in a dose-dependent manner, against a solvent control, using a dual-choice assay. This dataset was analysed using nominal logistic regression followed by an odds ratio comparison. RESULTS Gravid Ae. aegypti responded stage- and density-dependently to water conditioned with eggs, second- and fourth-instar larvae, and pupal exuviae, but not to water conditioned with pupae alone. Multi-choice assays demonstrated that gravid mosquitoes preferred to oviposit in water conditioned with fourth-instar larvae, over the other aquatic stage-conditioned water. Gravid Ae. aegypti were attracted, and generally stimulated, to oviposit in a dose-dependent manner to the individual identified synthetic odour blends for the different aquatic stages. CONCLUSIONS Intraspecific VOCs regulate oviposition site selection in Ae. aegypti in a stage- and density-dependent manner. We discuss the need for further studies to evaluate the identified synthetic blends to modulate the odour-mediated oviposition of Ae. aegypti under field conditions.
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Affiliation(s)
- Zaid Khan
- Disease Vector Group, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Box 190, 234 22, Lomma, Sweden
| | - Björn Bohman
- Disease Vector Group, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Box 190, 234 22, Lomma, Sweden
| | - Rickard Ignell
- Disease Vector Group, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Box 190, 234 22, Lomma, Sweden
| | - Sharon Rose Hill
- Disease Vector Group, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Box 190, 234 22, Lomma, Sweden.
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Hardy H, Harte SJ, Hopkins RJ, Mnyone L, Hawkes FM. The influence of manure-based organic fertilisers on the oviposition behaviour of Anopheles arabiensis. Acta Trop 2023:106954. [PMID: 37244404 DOI: 10.1016/j.actatropica.2023.106954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 05/23/2023] [Accepted: 05/24/2023] [Indexed: 05/29/2023]
Abstract
The rice agroecosystem provides suitable breeding habitat for many malaria vector species, and rice-adjacent communities are consequently exposed to a greater malaria transmission risk than non-rice-associated communities. As part of efforts to expand rice production in Africa, sustainable and climate-adapted practices such as the System of Rice Intensification (SRI) are being promoted. SRI encourages the use of organic fertilisers (OFs) such as cow and chicken dung, as opposed to inorganic industrially produced fertilisers, due to their lower resource cost, apparent benefit to the rice agroecosystem and as a means to reduce the greenhouse gas emissions associated with the production of industrial fertilisers. However, the impact of OFs on mosquito fauna is not well documented and may have knock-on consequences on malaria transmission risk. Here, we demonstrate, using dual choice egg count assays, that both cow and chicken dung modulate the oviposition behaviour of Anopheles arabiensis, a major malaria vector in Sub-Saharan Africa. A significantly reduced proportion of eggs were laid in water treated with either cow or chicken dung compared to untreated water, with higher dung concentrations resulting in further reduced proportions. When presented in competition, significantly fewer eggs were laid in water treated with chicken dung than with cow dung. Moreover, there was no evidence of egg retention in any experiment, including in no-choice experiments where only dung-containing dishes were available. These results suggest both cow and chicken dung may act as oviposition deterrents to malaria vector species and that the application of manure-based OFs in rice agriculture may modulate the oviposition behaviour of An. gambiae s.l. within agroecosystems. Quantification of the ammonia present in dung-infused water showed higher concentrations were present in the chicken dung infusion, which may be one contributing factor to the difference in observed deterrence between the two dung types. Deterrence of mosquito oviposition in OF-treated farms may potentially affect the overall production of malaria vectors within rice fields and their contribution to local malaria transmission.
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Affiliation(s)
- Harrison Hardy
- Natural Resources Institute, University of Greenwich, UK..
| | - Steven J Harte
- Natural Resources Institute, University of Greenwich, UK..
| | | | - Ladslaus Mnyone
- Institute of Pest Management, Sokoine University of Agriculture, Tanzania.; Department of Science, Technology and Innovation, Ministry of Education, Science and Technology, Tanzania..
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Li JQ, Zhu R, Yao WC, Yu HP, Huang JR, Wang Z, Sun XY, Yuan DH, Sun YY, Emam SS, Dewer Y, Zhu XY, Zhang YN. Chemosensory Protein 2 of Male Athetis lepigone Is Involved in the Perception of Sex Pheromones and Maize Volatiles. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:6277-6287. [PMID: 37068196 DOI: 10.1021/acs.jafc.3c00565] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
In moths, the interactions between chemosensory proteins (CSPs) and sex pheromones have yet to be comprehensively investigated. Here, we examined the function of AlepCSP2 in male Athetis lepigone based on protein expression, molecular docking, site-directed mutagenesis, fluorescence competitive binding analyses, and RNA interference (RNAi) experiments. We found that AlepCSP2 showed strong binding affinity for two sex pheromones and five maize volatiles and that binding was optimal under neutral conditions. Furthermore, we identified six amino acids as being key residues involved in the interaction between AlepCSP2 and multiple ligands. Further RNAi showed that siCSP2 males displayed consistently lower electroantennography responses to two sex pheromones and three maize volatiles at different dosages tested, and the mating rate also decreased significantly by 37.50%. These findings will contribute to characterizing the binding mechanisms of moth CSPs to sex pheromones and host volatiles and also identify unique targets for developing novel pest behavior disruptors.
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Affiliation(s)
- Jian-Qiao Li
- College of Life Sciences, Huaibei Normal University, Huaibei 235000, China
| | - Rui Zhu
- College of Life Sciences, Huaibei Normal University, Huaibei 235000, China
| | - Wei-Chen Yao
- College of Life Sciences, Huaibei Normal University, Huaibei 235000, China
| | - Hui-Ping Yu
- College of Life Sciences, Huaibei Normal University, Huaibei 235000, China
| | - Jian-Rong Huang
- Henan Key Laboratory of Crop Pest Control, MOA's Regional Key Lab of Crop IPM in Southern Part of Northern China, Institute of Plant Protection, Henan Academy of Agricultural Sciences, Zhengzhou 450002, China
| | - Zhen Wang
- College of Life Sciences, Huaibei Normal University, Huaibei 235000, China
| | - Xin-Yue Sun
- College of Life Sciences, Huaibei Normal University, Huaibei 235000, China
| | - Di-Hua Yuan
- College of Life Sciences, Huaibei Normal University, Huaibei 235000, China
| | - Yuan-Yuan Sun
- College of Life Sciences, Huaibei Normal University, Huaibei 235000, China
| | - Sekina S Emam
- Phytotoxicity Research Department, Central Agricultural Pesticide Laboratory, Agricultural Research Center, 7 Nadi El-Seid Street, Dokki, Giza 12618, Egypt
| | - Youssef Dewer
- Phytotoxicity Research Department, Central Agricultural Pesticide Laboratory, Agricultural Research Center, 7 Nadi El-Seid Street, Dokki, Giza 12618, Egypt
| | - Xiu-Yun Zhu
- College of Life Sciences, Huaibei Normal University, Huaibei 235000, China
| | - Ya-Nan Zhang
- College of Life Sciences, Huaibei Normal University, Huaibei 235000, China
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Weidig NC, Miller AL, Parker AT. The Goldilocks principle: Finding the balance between water volume and nutrients for ovipositing Culex mosquitoes (Diptera: Culicidae). PLoS One 2022; 17:e0277237. [PMID: 36355844 PMCID: PMC9648744 DOI: 10.1371/journal.pone.0277237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 10/21/2022] [Indexed: 11/12/2022] Open
Abstract
Females of container-breeding mosquito species use visual and chemical cues to determine suitable habitats to oviposit their eggs. Female Culex mosquitoes oviposit single egg rafts containing hundreds of eggs on the surface of water in container habitats. In this project, the effects of water volume and nutrient concentration were studied using three semi-controlled field assays to determine the role these parameters play on female Culex mosquito oviposition preference. The results of this study suggest female Culex prefer to oviposit in larger volumes of water and higher concentrations of nutrients separately, but chose intermediate conditions when presented with a combination of these two variables, which follows the Goldilocks principle. This choice may provide their offspring with optimal conditions for development by reducing intraspecific competition, thereby maximizing the biological fitness of the ovipositing Culex females.
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Affiliation(s)
- Noah C. Weidig
- Department of Biological Sciences, Northern Kentucky University, Highland Heights, Kentucky, United States of America
| | - Amber L. Miller
- Department of Biological Sciences, Northern Kentucky University, Highland Heights, Kentucky, United States of America
| | - Allison T. Parker
- Department of Biological Sciences, Northern Kentucky University, Highland Heights, Kentucky, United States of America
- * E-mail:
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Scolari F, Girella A, Croce AC. Imaging and spectral analysis of autofluorescence patterns in larval head structures of mosquito vectors. Eur J Histochem 2022; 66. [PMID: 36128772 PMCID: PMC9528535 DOI: 10.4081/ejh.2022.3462] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 08/03/2022] [Indexed: 11/23/2022] Open
Abstract
Autofluorescence (AF) in mosquitoes is currently poorly explored, despite its great potential as a marker of body structures and biological functions. Here, for the first time AF in larval heads of two mosquitoes of key public health importance, Aedes albopictus and Culex pipiens, is studied using fluorescence imaging and spectrofluorometry, similarly to a label-free histochemical approach. In generally conserved distribution patterns, AF shows differences between mouth brushes and antennae of the two species. The blue AF ascribable to resilin at the antennal bases, more extended in Cx. pipiens, suggests a potential need to support different antennal movements. The AF spectra larger in Cx. pipiens indicate a variability in material composition and properties likely relatable to mosquito biology, including diverse feeding and locomotion behaviours with implications for vector control.
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Affiliation(s)
- Francesca Scolari
- Institute of Molecular Genetics, Italian National Research Council (CNR), Pavia.
| | - Alessandro Girella
- Department of Chemistry - C.S.G.I., University of Pavia; Centro Interdipartimentale di Studi e Ricerche per la Conservazione del Patrimonio Culturale (CISRiC), University of Pavia.
| | - Anna Cleta Croce
- Institute of Molecular Genetics, Italian National Research Council (CNR), Pavia.
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Mulatier M, Boullis A, Vega-Rúa A. Semiochemical oviposition cues to control Aedes aegypti gravid females: state of the art and proposed framework for their validation. Parasit Vectors 2022; 15:228. [PMID: 35752845 PMCID: PMC9233825 DOI: 10.1186/s13071-022-05337-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 05/24/2022] [Indexed: 11/28/2022] Open
Abstract
In the fight against mosquito-borne diseases, odour-based lures targeting gravid females represent a promising alternative to conventional tools for both reducing mosquito populations and monitoring pathogen transmission. To be sustainable and effective, they are expected to use semiochemicals that act specifically against the targeted vector species. In control programmes directed against Aedes aegypti, several candidates of different origins (conspecifics, plants) have already been identified as potential oviposition attractants or repellents in laboratory experiments. However, few of these candidates have received validation in field experiments, studies depicting the active molecules and their mode of perception are still scarce, and there are several methodological challenges (i.e. lack of standardization, differences in oviposition index interpretation and use) that should be addressed to ensure a better reproducibility and accelerate the validation of candidates. In this review, we address the state of the art of the compounds identified as potential candidates for trap development against Ae. aegypti and their level of validation. We also offer a critical methodological analysis, highlight remaining gaps and research priorities, and propose a workflow to validate these candidates and to increase the panel of odours available to specifically trap Ae. aegypti.
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Affiliation(s)
- Margaux Mulatier
- Laboratory of Vector Control Research, Institute Pasteur of Guadeloupe, Lieu-dit Morne Jolivière, 97139, Les Abymes, Guadeloupe, France.
| | - Antoine Boullis
- TERRA, Gembloux Agro-Bio Tech, University of Liège, Avenue de la Faculté 2B, 5030, Gembloux, Belgium
| | - Anubis Vega-Rúa
- Laboratory of Vector Control Research, Institute Pasteur of Guadeloupe, Lieu-dit Morne Jolivière, 97139, Les Abymes, Guadeloupe, France
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van den Brandhof JG, Wösten HAB. Risk assessment of fungal materials. Fungal Biol Biotechnol 2022; 9:3. [PMID: 35209958 PMCID: PMC8876125 DOI: 10.1186/s40694-022-00134-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Accepted: 02/18/2022] [Indexed: 12/12/2022] Open
Abstract
Sustainable fungal materials have a high potential to replace non-sustainable materials such as those used for packaging or as an alternative for leather and textile. The properties of fungal materials depend on the type of fungus and substrate, the growth conditions and post-treatment of the material. So far, fungal materials are mainly made with species from the phylum Basidiomycota, selected for the mechanical and physical properties they provide. However, for mycelium materials to be implemented in society on a large scale, selection of fungal species should also be based on a risk assessment of the potential to be pathogenic, form mycotoxins, attract insects, or become an invasive species. Moreover, production processes should be standardized to ensure reproducibility and safety of the product.
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Affiliation(s)
- Jeroen G van den Brandhof
- Microbiology, Department of Biology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands
| | - Han A B Wösten
- Microbiology, Department of Biology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
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10
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Grass-like plants release general volatile cues attractive for gravid Anopheles gambiae sensu stricto mosquitoes. Parasit Vectors 2021; 14:552. [PMID: 34706760 PMCID: PMC8554987 DOI: 10.1186/s13071-021-04939-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 08/09/2021] [Indexed: 11/16/2022] Open
Abstract
Background Understanding the ecology and behaviour of disease vectors, including the olfactory cues used to orient and select hosts and egg-laying sites, are essential for the development of novel, insecticide-free control tools. Selected graminoid plants have been shown to release volatile chemicals attracting malaria vectors; however, whether the attraction is selective to individual plants or more general across genera and families is still unclear. Methods To contribute to the current evidence, we implemented bioassays in two-port airflow olfactometers and in large field cages with four live graminoid plant species commonly found associated with malaria vector breeding sites in western Kenya: Cyperus rotundus and C. exaltatus of the Cyperaceae family, and Panicum repens and Cynodon dactylon of the Poaceae family. Additionally, we tested one Poaceae species, Cenchrus setaceus, not usually associated with water. The volatile compounds released in the headspace of the plants were identified using gas chromatography/mass spectrometry. Results All five plants attracted gravid vectors, with the odds of a mosquito orienting towards the choice-chamber with the plant in an olfactometer being 2–5 times higher than when no plant was present. This attraction was maintained when tested with free-flying mosquitoes over a longer distance in large field cages, though at lower strength, with the odds of attracting a female 1.5–2.5 times higher when live plants were present than when only water was present in the trap. Cyperus rotundus, previously implicated in connection with an oviposition attractant, consistently elicited the strongest response from gravid vectors. Volatiles regularly detected were limonene, β-pinene, β-elemene and β-caryophyllene, among other common plant compounds previously described in association with odour-orientation of gravid and unfed malaria vectors. Conclusions The present study confirms that gravid Anopheles gambiae sensu stricto use chemical cues released from graminoid plants to orientate. These cues are released from a variety of graminoid plant species in both the Cyperaceae and Poaceae family. Given the general nature of these cues, it appears unlikely that they are exclusively used for the location of suitable oviposition sites. The utilization of these chemical cues for attract-and-kill trapping strategies must be explored under natural conditions to investigate their efficiency when in competition with complex interacting natural cues. Graphical abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s13071-021-04939-4.
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Wondwosen B, Dawit M, Debebe Y, Tekie H, Hill SR, Ignell R. Development of a chimeric odour blend for attracting gravid malaria vectors. Malar J 2021; 20:262. [PMID: 34107946 PMCID: PMC8191216 DOI: 10.1186/s12936-021-03797-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 06/01/2021] [Indexed: 11/29/2022] Open
Abstract
Background Odour-based tools targeting gravid malaria vectors may complement existing intervention strategies. Anopheles arabiensis are attracted to, and stimulated to oviposit by, natural and synthetic odours of wild and domesticated grasses associated with mosquito breeding sites. While such synthetic odour lures may be used for vector control, these may have limited efficacy when placed in direct competition with the natural source. In this study, workflows developed for plant-feeding pests was used to design and evaluate a chimeric odour blend based on shared attractive compounds found in domesticated grass odours. Methods Variants of a synthetic odour blend, composed of shared bioactive compounds previously identified in domesticated grasses, was evaluated sequentially in a two-choice olfactometer to identify a ratio-optimized attractive blend for malaria vectors. During this process, blends with ratios that were significantly more attractive than the previously identified synthetic rice blend were compared to determine which was most attractive in the two-choice olfactometer. To determine whether all volatile components of the most attractive blend were necessary for maximal attraction, subtractive assays were then conducted, in which individual components were removed for the most attractive blend, to define the final composition of the chimeric blend. Binary logistic regression models were used to determine significance in all two-choice assays. The chimeric blend was then assessed under field conditions in malaria endemic villages in Ethiopia, to assess the effect of dose, trap type, and placement relative to ground level. Field data were analyzed both descriptively and using a Welch-corrected t-test. Results A ratio-optimized chimeric blend was identified that significantly attracted gravid An. arabiensis under laboratory conditions. In the field, trap captures of An. arabiensis and Anopheles pharoensis were dependent on the presence of the lure, trap type (CDC, BG Sentinel and Suna traps), placement relevant to ground level, with low release rates generally luring more mosquitoes. Conclusions The workflow designed for the development of chimeric lures provides an innovative strategy to target odour-mediated behaviours. The chimeric lure identified here can be used in existing trapping systems, and be customized to increase sustainability, in line with goals of the Global Vector Control Response Group.
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Affiliation(s)
- Betelehem Wondwosen
- Department of Zoological Sciences, Addis Ababa University, PO Box 1176, Addis Ababa, Ethiopia
| | - Mengistu Dawit
- Department of Zoological Sciences, Addis Ababa University, PO Box 1176, Addis Ababa, Ethiopia.,Unit of Chemical Ecology, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Sundsvägen 14, PO Box 102, 230 53, Alnarp, Sweden
| | - Yared Debebe
- Department of Zoological Sciences, Addis Ababa University, PO Box 1176, Addis Ababa, Ethiopia.,Public Health Entomology Research Team, Ethiopian Public Health Institute, PO Box 1242, Addis Ababa, Ethiopia
| | - Habte Tekie
- Department of Zoological Sciences, Addis Ababa University, PO Box 1176, Addis Ababa, Ethiopia
| | - Sharon R Hill
- Unit of Chemical Ecology, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Sundsvägen 14, PO Box 102, 230 53, Alnarp, Sweden
| | - Rickard Ignell
- Unit of Chemical Ecology, Department of Plant Protection Biology, Swedish University of Agricultural Sciences, Sundsvägen 14, PO Box 102, 230 53, Alnarp, Sweden.
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12
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Konopka JK, Task D, Afify A, Raji J, Deibel K, Maguire S, Lawrence R, Potter CJ. Olfaction in Anopheles mosquitoes. Chem Senses 2021; 46:6246230. [PMID: 33885760 DOI: 10.1093/chemse/bjab021] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
As vectors of disease, mosquitoes are a global threat to human health. The Anopheles mosquito is the deadliest mosquito species as the insect vector of the malaria-causing parasite, which kills hundreds of thousands every year. These mosquitoes are reliant on their sense of smell (olfaction) to guide most of their behaviors, and a better understanding of Anopheles olfaction identifies opportunities for reducing the spread of malaria. This review takes a detailed look at Anopheles olfaction. We explore a range of topics from chemosensory receptors, olfactory neurons, and sensory appendages to behaviors guided by olfaction (including host-seeking, foraging, oviposition, and mating), to vector management strategies that target mosquito olfaction. We identify many research areas that remain to be addressed.
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Affiliation(s)
- Joanna K Konopka
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, 855 North Wolfe Street, 434 Rangos Building, Baltimore, 21205 MD, USA
| | - Darya Task
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, 855 North Wolfe Street, 434 Rangos Building, Baltimore, 21205 MD, USA
| | - Ali Afify
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, 855 North Wolfe Street, 434 Rangos Building, Baltimore, 21205 MD, USA
| | - Joshua Raji
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, 855 North Wolfe Street, 434 Rangos Building, Baltimore, 21205 MD, USA
| | - Katelynn Deibel
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, 855 North Wolfe Street, 434 Rangos Building, Baltimore, 21205 MD, USA
| | - Sarah Maguire
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, 855 North Wolfe Street, 434 Rangos Building, Baltimore, 21205 MD, USA
| | - Randy Lawrence
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, 855 North Wolfe Street, 434 Rangos Building, Baltimore, 21205 MD, USA
| | - Christopher J Potter
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, 855 North Wolfe Street, 434 Rangos Building, Baltimore, 21205 MD, USA
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13
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Dormont L, Mulatier M, Carrasco D, Cohuet A. Mosquito Attractants. J Chem Ecol 2021; 47:351-393. [PMID: 33725235 DOI: 10.1007/s10886-021-01261-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 02/18/2021] [Accepted: 03/02/2021] [Indexed: 01/01/2023]
Abstract
Vector control and personal protection against anthropophilic mosquitoes mainly rely on the use of insecticides and repellents. The search for mosquito-attractive semiochemicals has been the subject of intense studies for decades, and new compounds or odor blends are regularly proposed as lures for odor-baited traps. We present a comprehensive and up-to-date review of all the studies that have evaluated the attractiveness of volatiles to mosquitoes, including individual chemical compounds, synthetic blends of compounds, or natural host or plant odors. A total of 388 studies were analysed, and our survey highlights the existence of 105 attractants (77 volatile compounds, 17 organism odors, and 11 synthetic blends) that have been proved effective in attracting one or several mosquito species. The exhaustive list of these attractants is presented in various tables, while the most common mosquito attractants - for which effective attractiveness has been demonstrated in numerous studies - are discussed throughout the text. The increasing knowledge on compounds attractive to mosquitoes may now serve as the basis for complementary vector control strategies, such as those involving lure-and-kill traps, or the development of mass trapping. This review also points out the necessity of further improving the search for new volatile attractants, such as new compound blends in specific ratios, considering that mosquito attraction to odors may vary over the life of the mosquito or among species. Finally, the use of mosquito attractants will undoubtedly have an increasingly important role to play in future integrated vector management programs.
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Affiliation(s)
- Laurent Dormont
- CEFE, Univ Paul Valéry Montpellier 3, CNRS, Univ Montpellier, EPHE, IRD, Montpellier, France.
| | - Margaux Mulatier
- Institut Pasteur de Guadeloupe, Laboratoire d'étude sur le contrôle des vecteurs (LeCOV), Lieu-Dit Morne Jolivièrex, 97139, Les Abymes, Guadeloupe, France
| | - David Carrasco
- MIVEGEC, Univ. Montpellier, IRD, CNRS, Montpellier, France
| | - Anna Cohuet
- MIVEGEC, Univ. Montpellier, IRD, CNRS, Montpellier, France
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14
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Mwingira VS, Mboera LEG, Takken W. Synergism between nonane and emanations from soil as cues in oviposition-site selection of natural populations of Anopheles gambiae and Culex quinquefasciatus. Malar J 2021; 20:52. [PMID: 33478526 PMCID: PMC7819190 DOI: 10.1186/s12936-020-03575-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Accepted: 12/31/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Olfactory cues have been shown to have an important role in guiding gravid mosquito females to selected sites for egg laying. The objective of this study was to determine the influence of emanations from soil from a breeding site and the putative oviposition pheromone nonane on oviposition-site selection of natural populations of Anopheles gambiae sensu lato (s.l.) and Culex quinquefasciatus. METHODS This field-based study was conducted in Mvomero District in East-central Tanzania. In a dual-choice experimental set up, clay bowls were dug into the ground and filled with one of the following treatments: (i) distilled water + autoclaved soil (control), (ii) distilled water + soil from a natural mosquito breeding site, (iii) distilled water + nonane and (iv) distilled water + nonane + soil from a natural breeding site. Soil was dried and autoclaved or dried only before use. After five days of incubation, larvae were collected daily for 10 days. The median number of larvae per bowl per day was used as outcome measure. RESULTS Autoclaved soil had a significant attractive effect on oviposition behaviour of Cx. quinquefasciatus (median values ± s.e: 8.0 ± 1.1; P < 0.005) but no effect on An. gambiae (median value ± s.e: 0.0 ± 0.2; P = 0.18). Nonane and emanations from untreated soil significantly and positively influenced the selection of oviposition sites by both An. gambiae s.l. (median values ± s.e.: 12.0 ± 2.0 and 4.5 ± 1.5, respectively; P < 0.0001) and Cx. quinquefasciatus (median values ± s.e.: 19.0 ± 1.3 and 17.0 ± 2.0, respectively; P < 0.0001). A mixture of nonane and untreated soil caused a synergistic effect on oviposition behaviour in An. gambiae s.l. (median value ± s.e.: 23.5 ± 2.5; P < 0.0001) compared to either nonane (median values ± s.e.: 12.0 ± 2.0; P < 0.0001) or untreated soil alone (median value ± s.e.: 4.5 ± 1.5; P < 0.0001). A synergistic effect of nonane mixed with untreated soil was also found in Cx. quinquefasciatus (median value ± s.e.: 41.0 ± 2.1; P < 0.0001) compared to either nonane (median value ± s.e. 19.0 ± 1.3; P < 0.0001) or untreated soil alone (median value ± s.e.: 17.0 ± 2.0; P < 0.0001). The oviposition activity index for An. gambiae was 0.56 (P < 0.001) and for Cx. quinquefasciatus 0.59 (P < 0.0001). CONCLUSIONS The larval pheromone nonane and emanations from breeding-site soil both induced oviposition in wild An. gambiae s.l. and Cx. quinquefasciatus, with a synergistic effect when both stimuli were present simultaneously. This is the first study in which nonane is shown to cause oviposition under natural conditions, suggesting that this compound can potentially be exploited for the management of mosquito vectors.
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Affiliation(s)
- Victor S Mwingira
- Laboratory of Entomology, Wageningen University & Research, P.O. Box 16, 6700 AA, Wageningen, The Netherlands.,SACIDS Foundation for One Health, Sokoine University of Agriculture, Chuo Kikuu, P.O. Box 3297, Morogoro, Tanzania
| | - Leonard E G Mboera
- SACIDS Foundation for One Health, Sokoine University of Agriculture, Chuo Kikuu, P.O. Box 3297, Morogoro, Tanzania
| | - Willem Takken
- Laboratory of Entomology, Wageningen University & Research, P.O. Box 16, 6700 AA, Wageningen, The Netherlands.
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15
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Mwingira V, Mboera LEG, Dicke M, Takken W. Exploiting the chemical ecology of mosquito oviposition behavior in mosquito surveillance and control: a review. JOURNAL OF VECTOR ECOLOGY : JOURNAL OF THE SOCIETY FOR VECTOR ECOLOGY 2020; 45:155-179. [PMID: 33207066 DOI: 10.1111/jvec.12387] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Vector control is an important component of the interventions aimed at mosquito-borne disease control. Current and future mosquito control strategies are likely to rely largely on the understanding of the behavior of the vector, by exploiting mosquito biology and behavior, while using cost-effective, carefully timed larvicidal and high-impact, low-volume adulticidal applications. Here we review the knowledge on the ecology of mosquito oviposition behavior with emphasis on the potential role of infochemicals in surveillance and control of mosquito-borne diseases. A search of PubMed, Embase, Web of Science, Global Health Archive, and Google Scholar databases was conducted using the keywords mosquito, infochemical, pheromone, kairomone, allomone, synomone, apneumone, attractant, host-seeking, and oviposition. Articles in English from 1974 to 2019 were reviewed to gain comprehensive understanding of current knowledge on infochemicals in mosquito resource-searching behavior. Oviposition of many mosquito species is mediated by infochemicals that comprise pheromones, kairomones, synomones, allomones, and apneumones. The novel putative infochemicals that mediate oviposition in the mosquito subfamilies Anophelinae and Culicinae were identified. The role of infochemicals in surveillance and control of these and other mosquito tribes is discussed with respect to origin of the chemical cues and how these affect gravid mosquitoes. Oviposition attractants and deterrents can potentially be used for manipulation of mosquito behavior by making protected resources unsuitable for mosquitoes (push) while luring them towards attractive sources (pull). In this review, strategies of targeting breeding sites with environmentally friendly larvicides with the aim to develop appropriate trap-and-kill techniques are discussed.
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Affiliation(s)
- Victor Mwingira
- Laboratory of Entomology, Wageningen University and Research, P.O. Box 16, 6700 AA, Wageningen, The Netherlands
- National Institute for Medical Research, Amani Research Centre, P.O. Box 81, Muheza, Tanzania
| | - Leonard E G Mboera
- SACIDS Foundation for One Health, Sokoine University of Agriculture, P.O. Box 3297 Chuo Kikuu, Morogoro, Tanzania
| | - Marcel Dicke
- Laboratory of Entomology, Wageningen University and Research, P.O. Box 16, 6700 AA, Wageningen, The Netherlands
| | - Willem Takken
- Laboratory of Entomology, Wageningen University and Research, P.O. Box 16, 6700 AA, Wageningen, The Netherlands
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16
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Bokore GE, Ouma P, Onyango PO, Bukhari T, Fillinger U. A cross-sectional observational study investigating the association between sedges (swamp grasses, Cyperaceae) and the prevalence of immature malaria vectors in aquatic habitats along the shore of Lake Victoria, western Kenya. F1000Res 2020; 9:1032. [PMID: 33093949 PMCID: PMC7551511 DOI: 10.12688/f1000research.25673.2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/24/2020] [Indexed: 12/01/2022] Open
Abstract
Background: Strategies that involve manipulations of the odour-orientation of gravid malaria vectors could lead to novel attract-and-kill interventions. Recent work has highlighted the potential involvement of graminoid plants in luring vectors to oviposition sites. This study aimed to analyse the association between water-indicating graminoid plants (Cyperaceae, sedges), other abiotic and biotic factors and the presence and abundance of early instar
Anopheles larvae in aquatic habitats as a proxy indicator for oviposition. Methods: A cross-sectional survey of 110 aquatic habitats along the shores of Lake Victoria was done during the rainy season. Habitats were sampled for mosquito larvae using the sweep-net method and habitat characteristics recorded. Results:
Anopheles arabiensis was the dominant species identified from aquatic habitats. Larvae of the secondary malaria vectors such as
Anopheles coustani, An. rufipes and
An. maculipalpis were found only in habitats covered with graminoids, whereas
An. arabiensis, An. ziemanni and
An. pharoensis were found in both habitats with and without graminoid plants. The hypothesis that sedges might be positively associated with the presence and abundance of early instar
Anopheles larvae could not be confirmed. The dominant graminoid plants in the habitats were
Panicum repens,
Cynodon dactylon in the Poaceae family and
Cyperus rotundus in the Cyperaceae family. All of these habitats supported abundant immature vector populations. The presence of early instar larvae was significantly and positively associated with swamp habitat types (OR=22, 95% CI=6-86, P<0.001) and abundance of late
Anopheles larvae (OR=359, CI=33-3941, P<0.001), and negatively associated with the presence of tadpoles (OR=0.1, CI=0.0.01-0.5, P=0.008). Conclusions: Early instar malaria vectors were abundant in habitats densely vegetated with graminoid plants in the study area but no specific preference could be detected for any species or family. In search for oviposition cues, it might be useful to screen for chemical volatiles released from all dominant plant species.
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Affiliation(s)
- Getachew E Bokore
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya.,School of Physical and Biological Sciences, Department of Zoology, Maseno University, P.O. Box 333 - 40105, Maseno, Kenya.,Public Health Entomology Team, Ethiopian Public Health Institute, P.O. Box 1242, Addis Ababa, Ethiopia
| | - Paul Ouma
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya
| | - Patrick O Onyango
- School of Physical and Biological Sciences, Department of Zoology, Maseno University, P.O. Box 333 - 40105, Maseno, Kenya
| | - Tullu Bukhari
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya.,School of Physical and Biological Sciences, Department of Zoology, Maseno University, P.O. Box 333 - 40105, Maseno, Kenya
| | - Ulrike Fillinger
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya
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