Does acoustic signalling predict mating success in mosquito lines?

The control of mosquito transmitted diseases such as malaria, dengue fever, and Chikungunya is still largely dependent on mosquito population control. Unfortunately, many of the tools we use to control mosquito populations are currently threatened by the evolution of insecticide resistance. Researchers are developing new strategies to manage mosquito populations. Several new promising strategies involve genetic or reproductive control. In these cases, males will be mass reared in the laboratory and released into nature where they will need to compete with wild males for mates. These males will deliver technologies that will either reduce the mosquito population or the population's ability to transmit disease. Unfortunately, we know very little about mosquito mating behaviour. Specifically, we do not know what makes a male attractive to females.

In this project, we propose to investigate newly discovered acoustic signals to determine if we can use male signalling ability to accurately predict how laboratory reared males will perform in competition with wild males. So far we know that the presence of a convergence event it important for female choice, but we do not know which components of the signal she is paying attention to. First, we will measure signal components such as latency, rate, range, and consistency while recording mating interactions between live mosquitoes to determine which are most predictive of male mating success. Males used in releases will need to be reared in the laboratory. Thus, understanding how rearing practices influence male courtship signals is important. However, the role of environment in shaping these signals has not been investigated. We will use artificial playbacks to measure the signalling performance of males that have been subjected to various laboratory conditions. Finally, we will use this new knowledge to determine if harmonic convergence signalling ability is a predictor of how males will perform under field conditions. We will test males with low or high signalling performance against wild males in large field cages. This will allow us to test if acoustic measurement could be used as a high-throughput assay to males in rearing programs. At the conclusion of this project, we will have advanced our understanding of sexual selection in mosquitoes and developed a new tool for control programs.

Mosquito transmitted pathogens represent a substantial and emerging threat to global health. Several new reproductive and genetic control strategies will require the release of laboratory reared male mosquitoes which are able to successfully mate with field populations. However, we know surprisingly little about the determinants of male fitness and mating success. This lack of understanding of basic mosquito ecology has hampered the development of methods for assessing line quality. We have published evidence that mosquitoes use acoustic signals and that these signals are significant determinants of male mating success. In this application we will investigate the role of acoustic signalling in mate choice and assess the utility of acoustic signals as an indicator of male mosquito fitness. In order to meet the applied goals of rearing successful lines and developing robust, accurate methods for predicting male fitness, we must first better understand how environmental conditions affect acoustic signals and the relative contribution of acoustic signalling to total male fitness. First, we will measure signal components, such as latency and speed, while recording mating interactions between live mosquitoes to determine which are most predictive of male mating success. Second, we will use artificial playbacks to measure the signalling performance of males that have been subjected to various laboratory rearing conditions. Finally, we will use this new knowledge to determine if acoustic signalling ability is a predictor of how males will perform under field conditions. We will test males with low or high signalling performance against wild males in large field cages. This will allow us to test if high-throughput acoustic assays can be used to assess males in rearing programs. At the conclusion of this project, we will have advanced our understanding of mosquito sexual selection and aim to provide a new tool for mass rearing programs to assess mosquito line quality.

This research would benefit:
The commercial private sector and non-for-profit control projects would benefit from the development of a high throughput assay for assessing mosquito lines. The ability to test and optimized lines would be helpful for the design of large scale rearing production centers and would assist these parties in increasing the effectiveness and economic feasibility of large scale releases. We will provide these parties with key data on potential high-throughput assays for assess line quality and how rearing conditions affect male performance in competition with wild males. We are working closely with industry partners (see letters of support from Oxitech and Target Malaria). Project PI Cator is in active communication with these parties and will ensure thatresults of the project are made available to them directly and to the wider community through presentations and publications.

The wider public will benefit from this research because it will facilitate with implementation of novel control strategies for diseases that continue to be significant sources of death and suffering throughout much of the world. Additionally, this project will contribute to the UK's competitiveness in this area by training project staff in techniques and forging collaborations between UK academics, industry, and international partners.