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Cavagna A, Giardina I, Gucciardino MA, Iacomelli G, Lombardi M, Melillo S, Monacchia G, Parisi L, Peirce MJ, Spaccapelo R. Characterization of lab-based swarms of Anopheles gambiae mosquitoes using 3D-video tracking. Sci Rep 2023; 13:8745. [PMID: 37253765 DOI: 10.1038/s41598-023-34842-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 05/09/2023] [Indexed: 06/01/2023] Open
Abstract
Mosquito copulation is a crucial determinant of its capacity to transmit malaria-causing Plasmodium parasites as well as underpinning several highly-anticipated vector control methodologies such as gene drive and sterile insect technique. For the anopheline mosquitoes responsible for African malaria transmission, mating takes place within crepuscular male swarms which females enter solely to mate. However, the mechanisms that regulate swarm structure or that govern mate choice remain opaque. We used 3D-video tracking approaches and computer vision algorithms developed for the study of other complex biological systems to document swarming behavior of a lab-adapted Anopheles gambiae line in a lab-based setting. By reconstructing trajectories of individual mosquitoes lasting up to 15.88 s, in swarms containing upwards of 200 participants, we documented swarm-like behavior in both males and females. In single sex swarms, encounters between individuals were fleeting (< 0.75 s). By contrast, in mixed swarms, we were able to detect 79 'brief encounters' (> 0.75 s; < 2.5 s) and 17 longer-lived encounters (> 2.5 s). We also documented several examples of apparent male-male mating competition. These findings represent the first steps towards a more detailed and quantitative description of swarming and courtship behavior in one of the most important vectors of malaria.
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Affiliation(s)
- Andrea Cavagna
- CNR-ISC (National Research Council - Institute for Complex Systems), Rome, Italy
- Physics Department University Sapienza, Rome, Italy
- INFN Unità Di Roma 1, Rome, Italy
| | - Irene Giardina
- CNR-ISC (National Research Council - Institute for Complex Systems), Rome, Italy
- Physics Department University Sapienza, Rome, Italy
- INFN Unità Di Roma 1, Rome, Italy
| | | | - Gloria Iacomelli
- Department of Medicine and Surgery, University of Perugia, Perugia, Italy
| | - Max Lombardi
- Department of Medicine and Surgery, University of Perugia, Perugia, Italy
| | - Stefania Melillo
- CNR-ISC (National Research Council - Institute for Complex Systems), Rome, Italy.
- Physics Department University Sapienza, Rome, Italy.
| | - Giulia Monacchia
- Department of Medicine and Surgery, University of Perugia, Perugia, Italy
| | - Leonardo Parisi
- CNR-ISC (National Research Council - Institute for Complex Systems), Rome, Italy
- Physics Department University Sapienza, Rome, Italy
| | - Matthew J Peirce
- Department of Medicine and Surgery, University of Perugia, Perugia, Italy
| | - Roberta Spaccapelo
- Department of Medicine and Surgery, University of Perugia, Perugia, Italy.
- Centro Universitario Di Ricerca Sulla Genomica Funzionale (C.U.R.Ge.F), CIRM Italian Malaria Network, University of Perugia, Perugia, Italy.
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Mark-release-recapture experiment in Burkina Faso demonstrates reduced fitness and dispersal of genetically-modified sterile malaria mosquitoes. Nat Commun 2022; 13:796. [PMID: 35145082 PMCID: PMC8831579 DOI: 10.1038/s41467-022-28419-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 01/12/2022] [Indexed: 11/15/2022] Open
Abstract
Every year, malaria kills approximately 405,000 people in Sub-Saharan Africa, most of them children under the age of five years. In many countries, progress in malaria control has been threatened by the rapid spread of resistance to antimalarial drugs and insecticides. Novel genetic mosquito control approaches could play an important role in future integrated malaria control strategies. In July 2019, the Target Malaria consortium proceeded with the first release of hemizygous genetically-modified (GM) sterile and non-transgenic sibling males of the malaria mosquito Anopheles coluzzii in Burkina Faso. This study aimed to determine the potential fitness cost associated to the transgene and gather important information related to the dynamic of transgene-carrying mosquitoes, crucial for next development steps. Bayesian estimations confirmed that GM males had lower survival and were less mobile than their wild type (WT) siblings. The estimated male population size in Bana village, at the time of the release was 28,000 - 37,000. These results provide unique information about the fitness and behaviour of released GM males that will inform future releases of more effective strains of the A. gambiae complex. Release of genetically-modified sterile mosquitoes is a potential method of malaria control but has yet to be tested in the field. Here, the authors perform a mark-release-recapture experiment and show that genetically-modified mosquitoes have reduced survival and dispersal compared to wild-types.
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Nignan C, Poda BS, Sawadogo SP, Maïga H, Dabiré KR, Gnankine O, Tripet F, Roux O, Diabaté A. Local adaptation and colonization are potential factors affecting sexual competitiveness and mating choice in Anopheles coluzzii populations. Sci Rep 2022; 12:636. [PMID: 35022496 PMCID: PMC8755725 DOI: 10.1038/s41598-021-04704-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Accepted: 12/24/2021] [Indexed: 11/16/2022] Open
Abstract
The mating behaviour of the malaria vector Anopheles gambiae complex is an important aspect of its reproduction biology. The success of mosquito release programmes based on genetic control of malaria crucially depends on competitive mating between both laboratory-reared and wild individuals, and populations from different localities. It is known that intrinsic and extrinsic factors can influence the mating success. This study addressed some of the knowledge gaps about factors influcencing mosquito mating success. In semi-field conditions, the study compared the mating success of three laboratory-reared and wild allopatric An. coluzzii populations originating from ecologically different locations in Burkina Faso. Overall, it was found that colonization reduced the mating competitiveness of both males and females compared to that of wild type individuals. More importly, females were more likely to mate with males of their own population of origin, be it wild or colonised, suggesting that local adaptation affected mate choice. The observations of mating behaviour of colonized and local wild populations revealed that subtle differences in behaviour lead to significant levels of population-specific mating. This is the first study to highlight the importance of local adaptation in the mating success, thereby highlighting the importance of using local strains for mass-rearing and release of An. coluzzii in vector control programmes.
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Affiliation(s)
- Charles Nignan
- Institut de Recherche en Sciences de La Santé (IRSS), Bobo-Dioulasso, Burkina Faso.
- Laboratoire d'Entomologie Fondamentale Et Appliquée, Unité de Formation Et de Recherche en Sciences de La Vie Et de La Terre (UFR-SVT), Université Ouaga I Pr. Joseph KI-ZERBO, Ouagadougou, Burkina Faso.
| | - Bèwadéyir Serge Poda
- Institut de Recherche en Sciences de La Santé (IRSS), Bobo-Dioulasso, Burkina Faso
- Laboratoire d'Entomologie Fondamentale Et Appliquée, Unité de Formation Et de Recherche en Sciences de La Vie Et de La Terre (UFR-SVT), Université Ouaga I Pr. Joseph KI-ZERBO, Ouagadougou, Burkina Faso
- MIVEGEC, IRD, CNRS, University of Montpellier, Montpellier, France
| | | | - Hamidou Maïga
- Institut de Recherche en Sciences de La Santé (IRSS), Bobo-Dioulasso, Burkina Faso
| | - Kounbobr Roch Dabiré
- Institut de Recherche en Sciences de La Santé (IRSS), Bobo-Dioulasso, Burkina Faso
| | - Olivier Gnankine
- Laboratoire d'Entomologie Fondamentale Et Appliquée, Unité de Formation Et de Recherche en Sciences de La Vie Et de La Terre (UFR-SVT), Université Ouaga I Pr. Joseph KI-ZERBO, Ouagadougou, Burkina Faso
| | - Frédéric Tripet
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Keele, UK
| | - Olivier Roux
- Institut de Recherche en Sciences de La Santé (IRSS), Bobo-Dioulasso, Burkina Faso
- MIVEGEC, IRD, CNRS, University of Montpellier, Montpellier, France
| | - Abdoulaye Diabaté
- Institut de Recherche en Sciences de La Santé (IRSS), Bobo-Dioulasso, Burkina Faso
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Mumford JD, Leach AW, Benedict MQ, Facchinelli L, Quinlan MM. Maintaining Quality of Candidate Strains of Transgenic Mosquitoes for Studies in Containment Facilities in Disease Endemic Countries. Vector Borne Zoonotic Dis 2018; 18:31-38. [PMID: 29337661 PMCID: PMC5770121 DOI: 10.1089/vbz.2017.2208] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Transgenic mosquitoes are being developed as novel components of area-wide approaches to vector-borne disease control. Best practice is to develop these in phases, beginning with laboratory studies, before moving to field testing and inclusion in control programs, to ensure safety and prevent costly field testing of unsuitable strains. The process of identifying and developing good candidate strains requires maintenance of transgenic colonies over many generations in containment facilities. By working in disease endemic countries with target vector populations, laboratory strains may be developed and selected for properties that will enhance intended control efficacy in the next phase, while avoiding traits that introduce unnecessary risks. Candidate strains aiming toward field use must consistently achieve established performance criteria, throughout the process of scaling up from small study colonies to production of sufficient numbers for field testing and possible open release. Maintenance of a consistent quality can be demonstrated by a set of insect quality and insectary operating indicators, measured over time at predetermined intervals. These indicators: inform comparability of studies using various candidate strains at different times and locations; provide evidence of conformity relevant to compliance with terms of approval for regulated use; and can be used to validate some assumptions related to risk assessments covering the contained phase and for release into the environment.
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Affiliation(s)
- John D Mumford
- 1 Centre for Environmental Policy, Imperial College London , Ascot, United Kingdom
| | - Adrian W Leach
- 1 Centre for Environmental Policy, Imperial College London , Ascot, United Kingdom
| | - Mark Q Benedict
- 2 Entomology Branch, Centers for Disease Control and Prevention (CDC) , Atlanta, Georgia
| | - Luca Facchinelli
- 3 Department of Vector Biology, Liverpool School of Tropical Medicine , Liverpool, United Kingdom
| | - M Megan Quinlan
- 1 Centre for Environmental Policy, Imperial College London , Ascot, United Kingdom
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Quinlan MM, Birungi J, Coulibaly MB, Diabaté A, Facchinelli L, Mukabana WR, Mutunga JM, Nolan T, Raymond P, Traoré SF. Containment Studies of Transgenic Mosquitoes in Disease Endemic Countries: The Broad Concept of Facilities Readiness. Vector Borne Zoonotic Dis 2018; 18:14-20. [PMID: 29337664 PMCID: PMC5770120 DOI: 10.1089/vbz.2017.2189] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Genetic strategies for large scale pest or vector control using modified insects are not yet operational in Africa, and currently rely on import of the modified strains to begin preliminary, contained studies. Early involvement of research teams from participating countries is crucial to evaluate candidate field interventions. Following the recommended phased approach for novel strategies, evaluation should begin with studies in containment facilities. Experiences to prepare facilities and build international teams for research on transgenic mosquitoes revealed some important organizing themes underlying the concept of "facilities readiness," or the point at which studies in containment may proceed, in sub-Saharan African settings. First, "compliance" for research with novel or non-native living organisms was defined as the fulfillment of all legislative and regulatory requirements. This is not limited to regulations regarding use of transgenic organisms. Second, the concept of "colony utility" was related to the characteristics of laboratory colonies being produced so that results of studies may be validated across time, sites, and strains or technologies; so that the appropriate candidate strains are moved forward toward field studies. Third, the importance of achieving "defensible science" was recognized, including that study conclusions can be traced back to evidence, covering the concerns of various stakeholders over the long term. This, combined with good stewardship of resources and appropriate funding, covers a diverse set of criteria for declaring when "facilities readiness" has been attained. It is proposed that, despite the additional demands on time and resources, only with the balance of and rigorous achievement of each of these organizing themes can collaborative research into novel strategies in vector or pest control reliably progress past initial containment studies.
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Affiliation(s)
- M Megan Quinlan
- 1 Centre for Environmental Policy, Imperial College London , Ascot, United Kingdom
| | - Josephine Birungi
- 2 Uganda Virus Research Institute (UVRI) , Entebbe, Uganda
- 3 International Livestock Research Institute , Nairobi, Kenya
| | - Mamadou B Coulibaly
- 4 Université des Sciences , des Techniques et des Technologies de Bamako, Bamako, Mali
| | - Abdoulaye Diabaté
- 5 Institut de Recherche en Sciences de la Santé (IRSS)/Centre Muraz , Bobo Dioulasso, Burkina Faso
| | - Luca Facchinelli
- 6 Department of Vector Biology, Liverpool School of Tropical Medicine , Liverpool, United Kingdom
| | - Wolfgang Richard Mukabana
- 7 School of Biological Sciences, University of Nairobi , Nairobi, Kenya
- 8 Science for Health , Nairobi, Kenya
| | - James Mutuku Mutunga
- 9 International Center of Insect Physiology and Ecology (ICIPE) , Mbita Point, Kenya
| | - Tony Nolan
- 1 Centre for Environmental Policy, Imperial College London , Ascot, United Kingdom
| | - Peter Raymond
- 10 Donald Danforth Plant Science Center , St. Louis, Missouri
| | - Sékou F Traoré
- 4 Université des Sciences , des Techniques et des Technologies de Bamako, Bamako, Mali
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6
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Simões PMV, Gibson G, Russell IJ. Pre-copula acoustic behaviour of males in the malarial mosquitoes Anopheles coluzzii and Anopheles gambiae s.s. does not contribute to reproductive isolation. ACTA ACUST UNITED AC 2017; 220:379-385. [PMID: 28148817 DOI: 10.1242/jeb.149757] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 11/09/2016] [Indexed: 11/20/2022]
Abstract
We reveal that males of two members of the Anopheles gambiae s.l. species complex, Anopheles coluzzii and Anopheles gambiae s.s. (hereafter A. gambiae), which are both malaria vectors, perform a stereotypical acoustic behaviour in response to pure tones at frequencies that encompass the frequency range of the female's flight-tones. This behaviour resembles that described for Culex quinquefasciatus and consists of phonotactic flight initiated by a steep increase in wing-beat frequency (WBF) followed by rapid frequency modulation (RFM) of WBF when in close proximity to the sound source. RFM was elicited without acoustic feedback or the presence of a live female, but it appears to be a stereotypic behaviour in the immediate lead up to copula formation. RFM is an independent and different behavioural process from harmonic convergence interactions used by male-female pairs for mate recognition at earlier stages of mating. Acoustic threshold for RFM was used to plot behavioural audiograms from free-flying A coluzzii and A gambiae males. These audiograms were almost identical (minima ∼400 Hz) and encompassed the WBF ranges of A coluzzii (378-601 Hz) and A gambiae (373-590 Hz) females, indicating that males of the two species share similar frequency tuning and range. Furthermore, no differences were found between the two species in their WBFs, RFM behaviour or harmonic convergence ratios. These results indicate that assortative mating between A coluzzii and A gambiae is unlikely to be based on male-specific acoustic behaviours during RFM. The significance of these findings in relation to possible mechanisms for assortative mating is discussed.
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Affiliation(s)
- Patrício M V Simões
- Sensory Neuroscience Research Group, School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton BN2 4GJ, UK
| | - Gabriella Gibson
- Department of Agriculture, Health and Environment, Natural Resources Institute, University of Greenwich, Chatham, Kent ME4 4TB, UK
| | - Ian J Russell
- Sensory Neuroscience Research Group, School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton BN2 4GJ, UK
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Epopa PS, Millogo AA, Collins CM, North A, Tripet F, Benedict MQ, Diabate A. The use of sequential mark-release-recapture experiments to estimate population size, survival and dispersal of male mosquitoes of the Anopheles gambiae complex in Bana, a west African humid savannah village. Parasit Vectors 2017; 10:376. [PMID: 28784147 PMCID: PMC5547516 DOI: 10.1186/s13071-017-2310-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 07/26/2017] [Indexed: 12/14/2022] Open
Abstract
Background Vector control is a major component of the malaria control strategy. The increasing spread of insecticide resistance has encouraged the development of new tools such as genetic control which use releases of modified male mosquitoes. The use of male mosquitoes as part of a control strategy requires an improved understanding of male mosquito biology, including the factors influencing their survival and dispersal, as well as the ability to accurately estimate the size of a target mosquito population. This study was designed to determine the seasonal variation in population size via repeated mark-release-recapture experiments and to estimate the survival and dispersal of male mosquitoes of the Anopheles gambiae complex in a small west African village. Methods Mark-release-recapture experiments were carried out in Bana Village over two consecutive years, during the wet and the dry seasons. For each experiment, around 5000 (3407–5273) adult male Anopheles coluzzii mosquitoes were marked using three different colour dye powders (red, blue and green) and released in three different locations in the village (centre, edge and outside). Mosquitoes were recaptured at sites spread over the village for seven consecutive days following the releases. Three different capture methods were used: clay pots, pyrethroid spray catches and swarm sampling. Results Swarm sampling was the most productive method for recapturing male mosquitoes in the field. Population size and survival were estimated by Bayesian analyses of the Fisher-Ford model, revealing an about 10-fold increase in population size estimates between the end of dry season (10,000–50,000) to the wet season (100,000–500,000). There were no detectable seasonal effects on mosquito survival, suggesting that factors other than weather may play an important role. Mosquito dispersal ranged from 40 to 549 m over the seven days of each study and was not influenced by the season, but mainly by the release location, which explained more than 44% of the variance in net dispersal distance. Conclusion This study clearly shows that male-based MRR experiments can be used to estimate some parameters of wild male populations such as population size, survival, and dispersal and to estimate the spatial patterns of movement in a given locality.
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Affiliation(s)
- Patric Stephane Epopa
- Institut de Recherche en Sciences de la Santé / Centre Muraz, Bobo-Dioulasso, Burkina Faso.
| | | | | | - Ace North
- Department of Zoology, University of Oxford, Oxford, UK
| | - Frederic Tripet
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Keele, Staffordshire, UK
| | | | - Abdoulaye Diabate
- Institut de Recherche en Sciences de la Santé / Centre Muraz, Bobo-Dioulasso, Burkina Faso
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Das De T, Sharma P, Rawal C, Kumari S, Tavetiya S, Yadav J, Hasija Y, Dixit R. Sex specific molecular responses of quick-to-court protein in Indian malarial vector Anopheles culicifacies: conflict of mating versus blood feeding behaviour. Heliyon 2017; 3:e00361. [PMID: 28765838 PMCID: PMC5524224 DOI: 10.1016/j.heliyon.2017.e00361] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 02/06/2017] [Accepted: 07/13/2017] [Indexed: 02/05/2023] Open
Abstract
Understanding the molecular basis of mosquito behavioural complexity plays a central role in designing novel molecular tools to fight against their vector-borne diseases. Although the olfactory system plays an important role in guiding and managing many behavioural responses including feeding and mating, but the sex-specific regulation of olfactory responses remain poorly investigated. From our ongoing transcriptomic data annotation of olfactory tissue of blood fed adult female An. culicifacies mosquitoes; we have identified a 383 bp long unique transcript encoding a Drosophila homolog of the quick-to-court protein. Previously this was shown to regulate courtship behaviour in adult male Drosophila. A comprehensive in silico analysis of the quick-to-court (qtc) gene of An. culicifacies (Ac-qtc) predicts a 1536 bp single copy gene encoding 511 amino acid protein, having a high degree of conservation with other insect homologs. The age-dependent increased expression of putative Ac-qtc correlated with the maturation of the olfactory system, necessary to meet the sex-specific conflicting demand of mating (mate finding) versus host-seeking behavioural responses. Sixteen to eighteen hours of starvation did not alter Ac-qtc expression in both sexes, however, blood feeding significantly modulated its response in the adult female mosquitoes, confirming that it may not be involved in sugar feeding associated behavioural regulation. Finally, a dual behavioural and molecular assay indicated that natural dysregulation of Ac-qtc in the late evening might promote the mating events for successful insemination. We hypothesize that Ac-qtc may play a unique role to regulate the sex-specific conflicting demand of mosquito courtship behaviour versus blood feeding behaviour in the adult female mosquitoes. Further elucidation of this molecular mechanism may provide further information to evaluate Ac-qtc as a key molecular target for mosquito-borne disease management.
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Affiliation(s)
- Tanwee Das De
- Laboratory of Host-Parasite Interaction Studies, National Institute of Malaria Research, Sector-8, Dwarka, Delhi 110077, India
- Department of Biotechnology, Delhi Technological University, Shahbad Daulatpur, Main Bawana Road, Delhi 110042, India
| | - Punita Sharma
- Laboratory of Host-Parasite Interaction Studies, National Institute of Malaria Research, Sector-8, Dwarka, Delhi 110077, India
| | - Charu Rawal
- Laboratory of Host-Parasite Interaction Studies, National Institute of Malaria Research, Sector-8, Dwarka, Delhi 110077, India
| | - Seena Kumari
- Laboratory of Host-Parasite Interaction Studies, National Institute of Malaria Research, Sector-8, Dwarka, Delhi 110077, India
| | - Sanjay Tavetiya
- Laboratory of Host-Parasite Interaction Studies, National Institute of Malaria Research, Sector-8, Dwarka, Delhi 110077, India
| | - Jyoti Yadav
- Laboratory of Host-Parasite Interaction Studies, National Institute of Malaria Research, Sector-8, Dwarka, Delhi 110077, India
| | - Yasha Hasija
- Department of Biotechnology, Delhi Technological University, Shahbad Daulatpur, Main Bawana Road, Delhi 110042, India
| | - Rajnikant Dixit
- Laboratory of Host-Parasite Interaction Studies, National Institute of Malaria Research, Sector-8, Dwarka, Delhi 110077, India
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Achinko D, Thailayil J, Paton D, Mireji PO, Talesa V, Masiga D, Catteruccia F. Swarming and mating activity of Anopheles gambiae mosquitoes in semi-field enclosures. MEDICAL AND VETERINARY ENTOMOLOGY 2016; 30:14-20. [PMID: 26508420 DOI: 10.1111/mve.12143] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Revised: 06/18/2015] [Accepted: 07/23/2015] [Indexed: 06/05/2023]
Abstract
Anopheles gambiae Giles sensu stricto (Diptera: Culicidae) is the major Afro-tropical vector of malaria. Novel strategies proposed for the elimination and eradication of this mosquito vector are based on the use of genetic approaches, such as the sterile insect technique (SIT). These approaches rely on the ability of released males to mate with wild females, and depend on the application of effective protocols to assess the swarming and mating behaviours of laboratory-reared insects prior to their release. The present study evaluated whether large semi-field enclosures can be utilized to study the ability of males from a laboratory colony to respond to natural environmental stimuli and initiate normal mating behaviour. Laboratory-reared males exhibited spatiotemporally consistent swarming behaviour within the study enclosures. Swarm initiation, peak and termination time closely tracked sunset. Comparable insemination rates were observed in females captured in copula in the semi-field cages relative to females in small laboratory cages. Oviposition rates after blood feeding were also similar to those observed in laboratory settings. The data suggest that outdoor enclosures are suitable for studying swarming and mating in laboratory-bred males in field-like settings, providing an important reference for future studies aimed at assessing the comparative mating ability of strains for SIT and other vector control strategies.
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Affiliation(s)
- D Achinko
- Molecular Biology and Bioinformatics Unit, International Centre of Insect Physiology and Ecology, Nairobi, Kenya
- Department of Biochemistry and Molecular Biology, Egerton University, Njoro, Kenya
| | - J Thailayil
- Department of Life Sciences, Imperial College London, London, U.K
| | - D Paton
- Dipartimento di Medicina Sperimentale e Scienze Biochimiche, Universita degli Studi di Perugia, Perugia, Italy
| | - P O Mireji
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
- Division of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, U.S.A
| | - V Talesa
- Dipartimento di Medicina Sperimentale e Scienze Biochimiche, Universita degli Studi di Perugia, Perugia, Italy
| | - D Masiga
- Molecular Biology and Bioinformatics Unit, International Centre of Insect Physiology and Ecology, Nairobi, Kenya
| | - F Catteruccia
- Department of Life Sciences, Imperial College London, London, U.K
- Dipartimento di Medicina Sperimentale e Scienze Biochimiche, Universita degli Studi di Perugia, Perugia, Italy
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA, U.S.A
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10
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Heterosis Increases Fertility, Fecundity, and Survival of Laboratory-Produced F1 Hybrid Males of the Malaria Mosquito Anopheles coluzzii. G3-GENES GENOMES GENETICS 2015; 5:2693-709. [PMID: 26497140 PMCID: PMC4683642 DOI: 10.1534/g3.115.021436] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The success of vector control strategies aiming to decrease disease transmission via the release of sterile or genetically-modified male mosquitoes critically depends on mating between laboratory-reared males and wild females. Unfortunately, mosquito colonization, laboratory rearing, and genetic manipulations can all negatively affect male competitiveness. Heterosis is commonly used to produce domestic animals with enhanced vigor and homogenous genetic background and could therefore potentially improve the mating performance of mass-reared male mosquitoes. Here, we produced enhanced hybrid males of the malaria mosquito Anopheles coluzzii by crossing two strains colonized >35 and 8 years ago. We compared the amount of sperm and mating plug proteins they transferred to females, as well as their insemination rate, reproductive success and longevity under various experimental conditions. Across experiments, widespread adaptations to laboratory mating were detected in the older strain. In large-group mating experiments, no overall hybrid advantage in insemination rates and the amount of sperm and accessory gland proteins transferred to females was detected. Despite higher sperm activity, hybrid males did not appear more fecund. However, individual-male mating and laboratory-swarm experiments revealed that hybrid males, while inseminating fewer females than older inbred males, were significantly more fertile, producing larger mating plugs and drastically increasing female fecundity. Heterotic males also showed increased longevity. These results validate the use of heterosis for creating hybrid males with improved fitness from long-established inbred laboratory strains. Therefore, this simple approach could facilitate disease control strategies based on male mosquito releases with important ultimate benefits to human health.
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11
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Targeting male mosquito mating behaviour for malaria control. Parasit Vectors 2015; 8:347. [PMID: 26113015 PMCID: PMC4485859 DOI: 10.1186/s13071-015-0961-8] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 06/17/2015] [Indexed: 11/10/2022] Open
Abstract
Malaria vector control relies heavily on the use of Long-Lasting Insecticidal Nets (LLINs) and Indoor Residual Spraying (IRS). These, together with the combined drug administration efforts to control malaria, have reduced the death toll to less than 700,000 deaths/year. This progress has engendered real excitement but the emergence and spread of insecticide resistance is challenging our ability to sustain and consolidate the substantial gains that have been made. Research is required to discover novel vector control tools that can supplement and improve the effectiveness of those currently available. Here, we argue that recent and continuing progress in our understanding of male mating biology is instrumental in the implementation of new approaches based on the release of either conventional sterile or genetically engineered males. Importantly, further knowledge of male biology could also lead to the development of new interventions, such as sound traps and male mass killing in swarms, and contribute to new population sampling tools. We review and discuss recent advances in the behavioural ecology of male mating with an emphasis on the potential applications that can be derived from such knowledge. We also highlight those aspects of male mating ecology that urgently require additional study in the future.
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Villiard A, Gaugler R. Long-term Effects of Carbohydrate Availability on Mating Success of Newly Eclosed Aedes albopictus (Diptera: Culicidae) Males. JOURNAL OF MEDICAL ENTOMOLOGY 2015; 52:308-314. [PMID: 26334803 DOI: 10.1093/jme/tjv030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 02/16/2015] [Indexed: 06/05/2023]
Abstract
Sugar availability varies greatly in nature, and determining how this affects male mosquito fitness is essential for understanding population dynamics. We allowed male Aedes albopictus (Skuse) carbohydrate access for increasing intervals of time immediately after eclosion and we evaluated their fitness by comparing mortality, mating success, and sperm transfer. We compared individual male Ae. albopictus, which were offered water or 20% sucrose solution for 24, 48, or 72 h. As predicted, there were significant increases in fitness for each additional day of sucrose access. Following sugar exposure, we allowed males daily access to three virgin females. We assessed mating success through observation of spermatozoa in the female spermathecae. When individuals of the same age were compared, males with sugar access exhibited significantly greater mating success than water-treated males in all treatments. The total number of spermathecae filled by males with sugar access in the 48- and 72-h treatments was also significantly greater on some days; these were 3-5 d posteclosion in the 48-h treatment and 5-6 d posteclosion in the 72-h treatment. We conclude that extended sugar access at eclosion is important for maximizing fitness in male Ae. albopictus and should be applicable to sterile male release efforts, especially when laboratory-reared males suffered from other disadvantages. We recommend retaining adult males for 3 d posteclosion prior to release to improve their mating success in male release initiatives.
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Affiliation(s)
- Alexandra Villiard
- Center for Vector Biology, Department of Entomology, Rutgers University, 180 Jones Ave., New Brunswick, NJ 08901-8536.
| | - Randy Gaugler
- Center for Vector Biology, Department of Entomology, Rutgers University, 180 Jones Ave., New Brunswick, NJ 08901-8536
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Experimental swap of Anopheles gambiae's assortative mating preferences demonstrates key role of X-chromosome divergence island in incipient sympatric speciation. PLoS Genet 2015; 11:e1005141. [PMID: 25880677 PMCID: PMC4400153 DOI: 10.1371/journal.pgen.1005141] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 03/11/2015] [Indexed: 12/12/2022] Open
Abstract
Although many theoretical models of sympatric speciation propose that genes responsible for assortative mating amongst incipient species should be associated with genomic regions protected from recombination, there are few data to support this theory. The malaria mosquito, Anopheles gambiae, is known for its sympatric cryptic species maintained by pre-mating reproductive isolation and its putative genomic islands of speciation, and is therefore an ideal model system for studying the genomic signature associated with incipient sympatric speciation. Here we selectively introgressed the island of divergence located in the pericentric region of the X chromosome of An. gambiae s.s. into its sister taxon An. coluzzii through 5 generations of backcrossing followed by two generations of crosses within the introgressed strains that resulted in An. coluzzii-like recombinant strains fixed for the M and S marker in the X chromosome island. The mating preference of recombinant strains was then tested by giving virgin recombinant individuals a choice of mates with X-islands matching and non-matching their own island type. We show through genetic analyses of transferred sperm that recombinant females consistently mated with matching island-type males thereby associating assortative mating genes with the X-island of divergence. Furthermore, full-genome sequencing confirmed that protein-coding differences between recombinant strains were limited to the experimentally swapped pericentromeric region. Finally, targeted-genome comparisons showed that a number of these unique differences were conserved in sympatric field populations, thereby revealing candidate speciation genes. The functional demonstration of a close association between speciation genes and the X-island of differentiation lends unprecedented support to island-of-speciation models of sympatric speciation facilitated by pericentric recombination suppression. Anopheles gambiae is the most important vector of malaria in Africa. This species is undergoing speciation and a number of subpopulations have been identified which can produce viable hybrid offspring but are reproductively isolated through assortative mating and ecological adaptation. This complex structure provides an ideal system for studying the unique genetic and behavioural processes required for speciation. Anopheles gambiae’s subpopulations differ genetically in limited regions of their genomes called islands of speciation. Theoretical studies predict that these islands, characterized by restricted genetic rearrangements, may protect genes of assortative mating between emerging species, and are fundamental to the speciation process. We set out to test this prediction by performing complex genetic crosses between the sister species Anopheles coluzzii and Anopheles gambiae s.s. and creating recombinant strains differing only at their X-chromosome island of speciation. We show through behavioural studies that recombinant females consistently mated with matching island-type males thereby associating assortative mating genes with the X-island of divergence. By sequencing the genetic code of the recombinant strains and natural populations, we could confirm these findings and identify candidate assortative mating genes. These findings suggest an important role of divergence islands for the genetic and behavioural processes associated with speciation.
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Mating competitiveness of sterile male Anopheles coluzzii in large cages. Malar J 2014; 13:460. [PMID: 25424008 PMCID: PMC4258930 DOI: 10.1186/1475-2875-13-460] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 11/19/2014] [Indexed: 11/16/2022] Open
Abstract
Background Understanding the factors that account for male mating competitiveness is critical to the development of the sterile insect technique (SIT). Here, the effects of partial sterilization with 90 Gy of radiation on sexual competitiveness of Anopheles coluzzii allowed to mate in different ratios of sterile to untreated males have been assessed. Moreover, competitiveness was compared between males allowed one versus two days of contact with females. Methods Sterile and untreated males four to six days of age were released in large cages (~1.75 sq m) with females of similar age at the following ratios of sterile males: untreated males: untreated virgin females: 100:100:100, 300:100:100, 500:100:100 (three replicates of each) and left for two days. Competitiveness was determined by assessing the egg hatch rate and the insemination rate, determined by dissecting recaptured females. An additional experiment was conducted with a ratio of 500:100:100 and a mating period of either one or two days. Two controls of 0:100:100 (untreated control) and 100:0:100 (sterile control) were used in each experiment. Results When males and females consort for two days with different ratios, a significant difference in insemination rate was observed between ratio treatments. The competitiveness index (C) of sterile males compared to controls was 0.53. The number of days of exposure to mates significantly increased the insemination rate, as did the increased number of males present in the untreated: sterile male ratio treatments, but the number of days of exposure did not have any effect on the hatch rate. Discussion The comparability of the hatch rates between experiments suggest that An. coluzzii mating competitiveness experiments in large cages could be run for one instead of two days, shortening the required length of the experiment. Sterilized males were half as competitive as untreated males, but an effective release ratio of at least five sterile for one untreated male has the potential to impact the fertility of a wild female population. However, further trials in field conditions with wild males and females should be undertaken to estimate the ratio of sterile males to wild males required to produce an effect on wild populations.
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