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.
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.
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.
Organisations
- University College London (Fellow, Lead Research Organisation)
- Pasteur Institute of Bangui (Collaboration)
- University College London (Collaboration)
- TropIQ Health Sciences (Collaboration)
- Polo d'Innovazione di Genomica, Genetica e Biologia (Collaboration)
- Ifakara Health Institute (Collaboration)
- University of Perugia (Collaboration)
- IMPERIAL COLLEGE LONDON (Collaboration)
Publications
Andrés M
(2020)
Buzzkill: targeting the mosquito auditory system.
in Current opinion in insect science
Georgiades M
(2023)
Hearing of malaria mosquitoes is modulated by a beta-adrenergic-like octopamine receptor which serves as insecticide target.
in Nature communications
Loh YM
(2023)
The auditory efferent system in mosquitoes.
in Frontiers in cell and developmental biology
Somers J
(2022)
Hitting the right note at the right time: Circadian control of audibility in Anopheles mosquito mating swarms is mediated by flight tones.
in Science advances
Su M
(2023)
Acoustic Physiology in Mosquitoes
in Cold Spring Harbor Protocols
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 | 09/2019 |
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 | 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 |
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. |
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 | The experiments are still ongoing |
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 |
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 | 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 | The collaboration has just started |
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 |
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. |
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 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 | 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 | 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 |