AUTHOR=Hellhammer Fanny , Heinig-Hartberger Mareike , Neuhof Paul , Teitge Felix , Jung-Schroers Verena , Becker Stefanie C. 

TITLE=Impact of different diets on the survival, pupation, and adult emergence of Culex pipiens biotype molestus larvae, and infectability with the insect-specific Culex Y virus

JOURNAL=Frontiers in Tropical Diseases

VOLUME=Volume 4 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/tropical-diseases/articles/10.3389/fitd.2023.1107857

DOI=10.3389/fitd.2023.1107857

ISSN=2673-7515

ABSTRACT=The current rapidly advancing climate change will affect the transmission of arthropod-borne viruses (arboviruses) mainly through changes in vector populations. Especially mosquitoes of the Culex pipiens complex play a prominent role in virus transmission in central Europe. Factors that contribute to the vector population density and the ability of those vectors to transmit viral pathogens (vector competence) can include nutrition during larval stages. To test the influence of larval diet on larval survival and adult emergence as well as vector competence, several diets varying in their nutritional composition were compared using a newly established assay. We tested the effects of 17 diets or diet combinations on the fitness of 3rd instar larvae of Culex pipiens biotype molestus. Larval survival rates ranged from 43.33 to 94.44 % until day 7 in this setting. A refined testing of three out of the 17 previously tested diets including Tetra Pleco as routine feed, JBL NovoTab as significantly inferior feed, and KG as significantly superior feed with respect to the factor larval survival rate were tested in combination with Culex Y virus infection.
All Culex Y virus infected larvae showed a significant lower larval survival, as well as low pupation, and adult emergence rates. However, none of the tested diet in our study had a significant impact on larval survival in combination with viral infection. Furthermore, we were able to correlate several water quality parameters such as phosphate, nitrate, ammonium, electrical conductivity values, and low O2-saturations with reduced larval survival. Thus, we were able to demonstrate that Culex Y virus could be a suitable agent to reduce mosquito population density by reducing larval density, pupation-, and adult emergence rates. Especially in combination with some water quality parameters these effects can be even enhanced leading to a reduced mosquito density, and in turn to a transmission cycle of arboviruses. Furthermore, we demonstrated the infection of mosquito larvae with a viral pathogen for the first time in Culex pipiens biotype molestus.