Biogenic amines in malaria mosquitoes: from hearing to swarming behaviour

Lead Research Organisation: University College London
Department Name: Ear Institute

Abstract

Mosquitoes are more sensitive to sound than any other arthropod, by means of their fascinating tiny antennal ears, the Johnston 's organ (JO). In an organ smaller that a pin's head, male mosquitoes harbour around 15,000 auditory neurons roughly equalling the number of hair in human cochlea. Mosquitoes use their sophisticated JO's to recognize the flight tones of mating partners. Every day around sunset, male mosquitoes aggregate in areal swarms that attract females. Within swarms, male and female acoustically detect each other by their wing beats. Due to the necessity for mosquito mating, pre-mating acoustic interactions and swarming behaviour are prime targets for mosquito control tools. Despite this, the neurobiology of mosquito swarming behaviour, and the physiological mechanisms that induce it, are almost entirely unknown.
We have recently shown how the mosquito JO function is modulated by an auditory efferent system. This is remarkable as auditory efferent control was believed to exist only in vertebrates. We show that the biogenic amines octopamine and serotonin are released in the mosquito JO and modulate sound-induced mechanical and electrical responses, likely contributing to JO's sophistication as sound detector. Interestingly, biogenic amines induce swarming and social behaviour in other insects. Taken together and given the intimate relationship between hearing and swarming behaviour in mosquitoes I hypothesized that they also induce mosquito aggregation in swarms and tune the mosquito auditory sensitivity to the flight tone of mating partners to maximize mating success. I argue that interfering with serotonin and octopamine signalling pathways could be a novel mosquito control target to impair hearing and swarming and consequently hinder mosquito mating.
My preliminary data support this hypothesis: i) the levels of octopamine and serotonin receptors in the mosquito JO change during the time when mosquitoes are swarming, ii) the auditory sensitivity of male mosquito JO increases during swarming, and this effect is mimicked after injecting octopamine. In this project, I will use a multidisciplinary approach bridging the fields of molecular biology, physiology and behaviour to study the physiological and behavioural changes induced by octopamine and serotonin in malaria-transmitting Anopheles gambiae mosquitoes with the declared goal of devising novel vector control tools.
To investigate this, I will first analyse the connection between the octopaminergic and serotonergic signalling in the mosquito JO and the circadian clock. I will study if octopamine and serotonin levels change during swarming and how these changes reflect shifts in auditory sensitivity. I will then disrupt these pathways by generating serotonin and octopamine receptor mutants and study the auditory and swarming behaviour phenotypes. Finally, I aim to translate these findings into innovative mosquito control tools by using the acquired knowledge to disrupt swarming behaviour in semi-field settings in a malaria endemic country.

Planned Impact

The rapid emergence of insecticide resistance among mosquito populations, alongside behavioural adaptations enabling evasion of control tools, makes a compelling case for developing novel control interventions. Due to their necessity for mating, hearing and swarming are promising targets. However, they have been underexploited due to extensive gaps in knowledge of the mosquito auditory behaviour and the molecular mechanisms involved. This project will produce data in two main areas with potential public health impact: i) physiological and behavioural data of mosquito auditory sensitivity that can be translated into the development of acoustic traps to lure and kill mosquitoes and inform the development of acoustic sensors as a novel high-throughput method for mosquito surveillance; ii) potential of interfering BA signalling to impair mosquito mating. OA/5-HT signal through G-protein coupled receptors that are considered promising targets for the development of next generation insecticides. Interestingly, OA (invertebrate counterpart of noradrenaline) is preferably synthetized in invertebrates and is only present as traces in mammals, so their receptors are promising potential targets for highly specific insecticides. Building on this project, I will develop a research career focused on providing rigorous physiological and behavioural data to incorporate acoustic traps and swarming impairment approaches into the spectrum of interventions to fight mosquito vector diseases.
The findings will be relevant for a broad audience. Medical entomologist and other public health stakeholders working in malaria control will be interested in the results, as evidence-based practices for malaria control con be derived from them. To reach them I will attend applied research conferences where different actors working on malaria control come together.
The project will also shed light on the molecular mechanisms underlying a fascinating sensory organ. I will characterize the first auditory efferent system describe in insects. This is highly relevant for other academic audiences, such as insect physiologists and vector biologists. Findings will reach these scientists by participating in conferences and publishing the research in high impact and open access journals.
The general public will also benefit from the results, as mosquito-borne diseases are a cause of mortality and morbidity worldwide, and mosquito species with the potential to transmit disease are spreading in Europe, due to the increase in international travel and the climate change. Different outreach activities will be organized to ensure that the research relevance has an impact on the wider public. In particular, public engagement activities will be performed in schools, both in UK and Tanzania, to ensure that future generations understand the importance of mosquito-borne disease and how to better protect themselves against mosquito bites.
 
Description This award has allowed us to achieve a deeper understanding of the audiory role of octopamine and serotonin in malaria mosquitoes. We described an beta adrenergic receptor as essential to mediate octopamine auditory function and showed its potential as insecticide target. We have also conducted several studies to assess the implication of disrupting mosquito auditory function for mosquito mating, and investigated how these processes can be targeted using insectides. These results will be published soon.
The characetrization of serotonin's role in the mosquito ear will extend into the Renewal period. During the inital grant, we generated mutant mosquitoes of three different serotonin receptors and analysed their auditory, mating and swarming phenotype. Our findings point at a connection between serotonin and the mosquito circadian clock to modulate mosquito audition.
Moreover, we have pushed the field of mosquito auditory neuroscience at the international level, as recognized by the funding and conference invitations received. We have also established several multidisciplinary collaborations, including with Sub-Saharan partners, to adress the complexity of our research topic from a holistic perspective, and maximize its impact for vector control
Exploitation Route This research is opening the field of mosquito auditory neuroscience, providing methodological and analytical tools to support the community. Our ideas are also contributing to consider if targeting the mosquito auditory system could be used for vector control. This has been recognized by different stakeholders and has the potential to incorporate behavioural modificatoin as alternative approach for mosquito control.
Sectors Agriculture

Food and Drink

Environment

Pharmaceuticals and Medical Biotechnology

URL https://www.neuromosquitolab.org/publications
 
Description We are establishing collaborations with the Bill and Melinda gates foundation to push forward our line of research and apply it to mosquito conrol. The PI has just recently been invited to the Insecticide Active Ingredient Accelerator Consortium Convening (organised by Gates Foundation Malaria Team) to develop novel insecticides for malaria control. Our ideas and research can contribute to incorporate behavioural control and mosquito mating disruption as alternative tools to control disease transmitting mosquitoes.
First Year Of Impact 2024
Sector Pharmaceuticals and Medical Biotechnology
Impact Types Societal

 
Description 752472 NEURO-SWARM - Efferent modulation of auditory sensitivity in mosquitoes: From auditory transduction to swarming behaviour
Amount € 183,455 (EUR)
Funding ID 752472 NEURO-SWARM 
Organisation European Commission 
Sector Public
Country European Union (EU)
Start 01/2017 
End 03/2019
 
Description Biogenic amines in malaria mosquitoes: from hearing to swarming behaviour
Amount £55,327 (GBP)
Funding ID ISSF3/ H17RCO/NG21 
Organisation Wellcome Trust 
Sector Charity/Non Profit
Country United Kingdom
Start 01/2020 
End 12/2021
 
Description Characterising the mating songs of malaria mosquitoes in Tanzania.
Amount £2,000 (GBP)
Organisation University College London 
Department UCL Global Engagement Office
Sector Academic/University
Country United Kingdom
Start 08/2019 
End 09/2019
 
Description Disrupting octopamine signalling for mosquito control
Amount £87,189 (GBP)
Organisation University College London 
Department UCL Global Engagement Office
Sector Academic/University
Country United Kingdom
Start 01/2020 
End 07/2020
 
Description Fellowship, UKRI FLF
Amount £595,479 (GBP)
Funding ID MR/Y011732/1 
Organisation United Kingdom Research and Innovation 
Sector Public
Country United Kingdom
Start 04/2024 
End 04/2027
 
Description Implications of insecticide resistance mutations for the mating behaviour of malaria mosquitoes in African cities
Amount £5,000 (GBP)
Organisation University College London 
Sector Academic/University
Country United Kingdom
Start 03/2023 
End 04/2023
 
Description OCT-OVA: Finding the mechanism of Octß2-dependent mosquito infertility
Amount € 289,178 (EUR)
Funding ID 101155276 (Marie Curie Global Individual Fellowship awarded to David Ellis, we act as hosting lab upon his return to the Europe) 
Organisation European Commission 
Sector Public
Country European Union (EU)
Start 05/2024 
End 06/2027
 
Description Programa ATRAE
Amount € 993,375 (EUR)
Funding ID ATR2023-145654 
Organisation Ministry of Science and Innovation (MICINN) 
Sector Public
Country Spain
Start 03/2025 
End 03/2029
 
Description Testing whether Rdl mutations are linked to Anopheles urban adaptation
Amount $28,898 (USD)
Funding ID INV-072333 
Organisation Bill and Melinda Gates Foundation 
Sector Charity/Non Profit
Country United States
Start 04/2024 
End 07/2024
 
Title Analysing swarming behaviour of disease-transmitting mosquitoes 
Description In collaboration with the University of Perugia in Italy, we are developing a set of tools to analyse visually and acoustically the swarming behaviour of malaria mosquitoes. 
Type Of Material Physiological assessment or outcome measure 
Year Produced 2023 
Provided To Others? No  
Impact This is still work in progress 
 
Title Knock-outs of three serotonin receptors in malaria mosquitoes 
Description We have used the genome-editing technique CRISPR-Cas9 to generate three Anopheles gambiae mosquito lines, each mutant for a different serotonin receptor. 
Type Of Material Biological samples 
Year Produced 2022 
Provided To Others? No  
Impact Serotonin is an important neurotransmitter that regulates different insect behaviors. These mutant lines will enable the research community to investigate the role of serotonin receptors in different biological processes, and to understand whether serotonin pathways can be targeted as part of novel mosquito control strategies. The lines will be available to the research community upon publication the results. 
 
Title New antibody against three serotonin receptors in the malaria mosquito 
Description Antibodies against three different serotonin receptors of the malaria mosquito Anopheles gambiae where generated by immunizing guinea pigs and rabbits using short peptides uniques to these receptors. We are still testing the specificity these antibodies and we will make them available once the results are published 
Type Of Material Antibody 
Year Produced 2022 
Provided To Others? No  
Impact These antibodies will enable to study the cellular and suocelular localization of serotonin receptors in the malaria mosquito. Serotonin is a biogenic amine neurotransmitter that is involved in controlling essential insect behaviors. Our antibody will contribute to understand the biological function that serotonin plays in malaria mosquitoes. 
 
Title Hearing of malaria mosquitoes is modulated by a beta-adrenergic-like octopamine receptor which serves as insecticide target 
Description Transcriptomic data of the mosquito ear 
Type Of Material Database/Collection of data 
Year Produced 2023 
Provided To Others? Yes  
Impact Impact on the community to investigate the molecular pathways underpinning mosquito hearing 
URL https://edoc.unibas.ch/95973/
 
Description Analysis of the effects of altering octopamine receptors in Plasmodium transmission in Anopheles gambiae 
Organisation TropIQ Health Sciences
Country Netherlands 
Sector Private 
PI Contribution This partnership aims at studying whether knocking-out octopamine receptors in the malaria mosquito Anopheles gambiae would lead to a reduced transmission of Plasmodium parasites by the mosquitoes. We have provided TropIQ with two different mosquito lines, each mutant for a different octopamine receptor.
Collaborator Contribution TropIQ will perform Standard Membrane Feeding Assays (SMFA) with GFP expressing Plasmodium infected blood and the infection status will be determined by luminescence assays.
Impact This collaboration showed that the octopamine beta-2 adrenergic receptor, AgOctbeta , is not implicated in the infection of An. gambiae mosquitoes by Plasmodium
Start Year 2021
 
Description Biogenic amines as novel targets to fight mosquito-borne diseases 
Organisation Ifakara Health Institute
Country Tanzania, United Republic of 
Sector Charity/Non Profit 
PI Contribution Knowledge on the basic biology of biogenic amines and their role in mosquito audition and swarming behaviour. Equipment to analyze this behaviour in the field.
Collaborator Contribution Medical entomology knowledge to translate our findings into mosquito control strategies. Semi-field facilities and mosquito lines to analyze mosquito swarming behaviour.
Impact ANTI-Vec Net annual meeting, June 20-21, London, United Kingdom: The acoustic landscape of disease transmitting vectors. Andres M, Su M, Somers J, Georgiades M, Ntabaliba W, Spaccapelo, R, Moore S, Albert J. Oral presentation. GCRF: UCL Internal Small Grant, 01/01-30/06/2020, Awardee: Marta Andres de Miguel, Amount awarded: £87,189.48 Publication: Georgiades M, Alampounti CA, Somers J, Su M, Ellis D, Bagi J, Terrazas-Duque D, Tytheridge S, Ntabaliba W, Moore S, Albert J, Andrés M. Hearing of malaria mosquitoes is modulated by a beta-adrenergic-like octopamine receptor which serves as insecticide target. Nat Commun 14, 4338 (2023). doi: https://doi.org/10.1038/s41467-023-40029-y
Start Year 2018
 
Description Drug discovery: developing a novel insecticide with antagonistic activity on malaria mosquito octopamine receptors 
Organisation University College London
Department School of Pharmacy
Country United Kingdom 
Sector Academic/University 
PI Contribution In our team, we have identified an octopamine receptor that might be a potential target for the development of novel insecticides due t the effects of blocking its activity on mosquito mating and egg development. In collaboration with Matthew Todd from UCL School of Pharmacy, we are looking for funding to develop new molecules with insecticide potential to block the activity of these receptors. We will work in the development of a cell line to express the receptor and study the effect of potential blockers at cellular and physiological level
Collaborator Contribution Matthew Todd's team will run a virtual screening to identify suitable molecules to block these receptors, and will further optimize select molecules to increase their insecticide potential.
Impact We submitted a WT Innovator Award that was not awarded but we preparing other applications to fund this research
Start Year 2021
 
Description Generation of biogenic amine receptor mutants 
Organisation Imperial College London
Country United Kingdom 
Sector Academic/University 
PI Contribution Genetic constructs to generate mosquito mutant lines
Collaborator Contribution Generation of mutant mosquito lines
Impact The analysis of the mutant auditory phenotypes will be included in a publication that is almost ready for submission
Start Year 2018
 
Description Genetics pathways underlying sexual dimorphism in malaria mosquito mating 
Organisation Imperial College London
Country United Kingdom 
Sector Academic/University 
PI Contribution We will analyse the auditory and mating phenotype of different mosquito transgenic lines generated by IC where different components of the sex determination pathway have been knocked out
Collaborator Contribution Our partner has generated the transgenic lines and conducted a preliminary assessment of the different mosquito lines
Impact We will start with the phenotypic characterization of the lines in April 2024
Start Year 2023
 
Description Implications of the GABA receptor rdl in modulating mosquito mating behaviour in noisy environments 
Organisation Pasteur Institute of Bangui
Country Central African Republic 
Sector Academic/University 
PI Contribution We have designed the study to combine laboratory and field studies to define the role of the GABA receptor Rdl in mediating the acoustic recognition of the mating partner in malaria mosquitoes. In particular, we are interested in analysing how mutations in Rdl that cause resistance to the insecticide dieldrin might confer and advantage for the detection of the mating partners in noisy areas of African cities. The laboratory studies include mating, phonotaxis and auditory tests. The field studies will include the molecular characterization of the mosquito species and Rdl allelic composition of mosquitoes detected in cities and rural areas in Central African Republic.
Collaborator Contribution Researchers at Institut Pasteur de Bangui will conduct the field studies to collect mosuqitoes in swarms and perform the molecular characterization
Impact This collaboration has resulted in collecting field data on Rdl allelic composition in rural and urban areas in the city of Bangui and its sourroundings. In parallel, laboratory data are collected at UCL to analyse the relationship between Rdl resistance mutations and the increased mating fitness of mosquitoes in noisy environments. Work is still in progress.
Start Year 2023
 
Description Modelling the effects of disrupting mosquito mating in malaria transmission 
Organisation Bill and Melinda Gates Foundation
Country United States 
Sector Charity/Non Profit 
PI Contribution We are using our experimental data to test a malaria model developed by the Gates foundation (https://docs.idmod.org/projects/emod-malaria/en/latest/), and to study if it can be improved by adding new parameters that incorporate the effects of disrupting mosquito mating behaviour
Collaborator Contribution Our partners are the modelling experts and they are training a PhD student in our lab to run the model and to incorporate potential novel parameters.
Impact This is work in progress
Start Year 2023
 
Description Mosquito swarming behaviour analysis in the laboratory 
Organisation University of Perugia
Country Italy 
Sector Academic/University 
PI Contribution Mosquito mutant lines and equipment to analyze the mosquito swarming behaviour of mosquitoes in laboratory conditions.
Collaborator Contribution Knowledge on how to induce mosquito swarming behaviour and large cage facilities to study this behaviour. 3D recording system to analyse the trajectories of mosquitoes flying with the swarm. One serotonin receptor line has been tested, showing swarming behaviour phenotypes. Two more lines need to be analysed.
Impact ANTI-Vec Net annual meeting, June 20-21, London, United Kingdom: The acoustic landscape of disease transmitting vectors. Andres M, Su M, Somers J, Georgiades M, Ntabaliba W, Spaccapelo, R, Moore S, Albert J. Oral presentation. Publiation: Somers J, Georgiades M, Su MP, Bagi J, Andrés M, Alampounti A, Mills G, Ntabaliba W, Moore S, Spaccapelo R, Albert J. (2022) Hitting the right note at the right time: Circadian control of audibility in Anopheles mosquito mating swarms is mediated by flight tones. Science Advances 6 (2): eabl4844. doi: 10.1126/sciadv.abl4844.
Start Year 2017
 
Description Swarming behaviour analysis 
Organisation Polo d'Innovazione di Genomica, Genetica e Biologia
Country Italy 
Sector Academic/University 
PI Contribution We provided polo GBB with the octopamine receptor mutants to be analysed
Collaborator Contribution They performed the analysis of the mating behaviour of the octopamine receptor mutants. They provided the facilities, the analytical pipeline and the staff to perform the analysis
Impact The data has been used as preliminary data for further experiments in the lab
Start Year 2019
 
Description Conference keynote speaker 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact Auditory neuromodulation in mosquitoes: implications for mosquito behaviour; Keynote speaker; Invertebrate Sound and Vibration 2023, March 30 - 2 April; Lincoln; United Kingdom.
Year(s) Of Engagement Activity 2023
 
Description Conference oral presentation 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact Conference oral presentation, The acoustic landscape of disease transmitting vectors; Oral presentation; Ellis D, Freeman E, Bagi J, Tytheridge S, Terrazas D, Andres M; ANTI-Vec Net annual meeting; February 26-March 1 2023; Kifili, Kenya.
Year(s) Of Engagement Activity 2023
 
Description Conference presentation - ANTI-Vec Net annual meeting 2023 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact Investigating the molecular basis of disease-transmitting mosquito hearing and swarming behaviour for mosquito control; Oral presentation; Ellis D, Freeman E, Bagi J, Tytheridge S, Terrazas D, Andres M; ANTI-Vec Net annual meeting; February 26-March 1 2023; Kifili, Kenya.
Year(s) Of Engagement Activity 2023
 
Description Conference presentation - EMBO Conference "Molecular and Population Biology of Mosquitoes and Other Disease Vectors" 2022 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact 2022, EMBO Conference "Molecular and Population Biology of Mosquitoes and Other Disease Vectors", Julio 23-28, Kolymbari, Grecia: Neuromodulation of malaria mosquito hearing and swarming behaviour. Presentación oral, session chair.
Year(s) Of Engagement Activity 2022
 
Description Conference presentation - EMBO Conference "Molecular and Population Biology of Mosquitoes and Other Disease Vectors" 2019 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact 2019, EMBO Conference "Molecular and Population Biology of Mosquitoes and Other Disease Vectors", July 22-26, Kolymbari, Greece: Biogenic amines and the modulation of mosquito auditory physiology during swarming behavior. Oral turbo presentation.
Year(s) Of Engagement Activity 2019
 
Description Crick Institute - Neuroscience Interest Group 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Postgraduate students
Results and Impact Interest group based at the Crick Institute. We participate as associate members. The group meets every two weeks to discuss different neuroscience topics based on the research performed by the participating groups.
Year(s) Of Engagement Activity 2020,2021
 
Description Invited conference talk 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Supporters
Results and Impact Targeting mosquito audition for vector control; Invited speaker; Insecticide Active Ingredient Accelerator Consortium Convening (organised by Gates Foundation Malaria Team), February 8-9, 2024; University of Florida in Gainesville, USA.
Year(s) Of Engagement Activity 2023
 
Description Online seminar (World Wide Neuro) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact 15 people attended the online presentation. A scientific discussion followed and open new ways for collaborations with research groups at the Crick Institute
Year(s) Of Engagement Activity 2020
 
Description Pint of Science 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact Informal talk on our research in a London pub to engage with the general public
Year(s) Of Engagement Activity 2023
URL https://pintofscience.co.uk/event/to-hear-is-to-believe-the-art-of-sound-and-how-science-can-explain...
 
Description Seminar presentation - Cajal Xmas Meeting 2020 (online) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Other audiences
Results and Impact Cajal Xmas Meeting 2020. Online seminar: Octopamine signalling in the mosquito ear: from sensory modulation to disease control.
Year(s) Of Engagement Activity 2020
 
Description Seminar presentation - University of Leicester 2023 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Other audiences
Results and Impact Neurogenetics seminar, University of Leicester, United Kingdom: Auditory neuromodulation in malaria mosquitoes.
Year(s) Of Engagement Activity 2023
 
Description Seminar presentation - University of Nagoya 2022 (online) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Other audiences
Results and Impact University of Nagoya YLC Salon. Online seminar: Octopamine as a key neuromodulator of malaria mosquito hearing.
Year(s) Of Engagement Activity 2022