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Version of Impact of Bacterial Symbionts on Host Growth and Mating Competitiveness in Mass-reared Mosquitoes
To introduce myself: I am Alessandro Roman, ESR15 PhD candidate under the European Joint Doctoral Programme (EJD), Insect Doctors. I am from Italy, and I moved to Penryn (Cornwall, UK) last September 2020, to start working at Exeter University (UK). My PhD project involve also the University of Wageningen (NL), and FAO/IAEA (AU). The insect model of my project is Aedes aegypti, also known as yellow fever mosquito.
Over the last 20 years, the importance of studying mosquito control techniques based on mass released of males, such as the Sterile Insect Technique (SIT), expanded rapidly, due to the well-known role of these insects as a vector of human pathogens. Currently a ratio of five sterile males over one wild type is needed in SIT control programs, this translates to very many millions of insects where these mosquitoes are prevalent. Consequently, increase the efficacy and reduce the costs of mosquito rearing are two of the major aims of this sector. Interestingly, insect symbionts are known to play a vital role in metabolisms and several symbiotic bacteria have been identified as promoting host growth.
First step of this research project was to establish an Aedes aegypti rearing system. This initial process involved trainings on how to synchronise larval hatching, how to administer blood through Hemotek® Membrane Feeding System and manipulate the mosquitoes in each rearing phase. These are important steps in order to obtain batches of eggs for controlled experiments.
First, we set out to understand how development and time to pupation are affected by the presence of specific bacterial symbionts in the mosquito gut. After some encouraging results we are currently carrying out metagenomics analysis of samples are in progress. Molecular tools for following symbiont’s colonization have been developed, such as the design of specific PCR primers and the preparation of antibiotic selective growth media. At this stage, follow-up bioassays will be performed to study the host’s gene expression profile after the inoculation with previously selected bacteria species.
Information obtained during this initial period are leading to new questions and hypotheses that will be explored during the Project.