Larval Competition between and Mosquitoes Carries over to Higher Arboviral Infection during Their Adult Stage.

The common house mosquito () is a native vector for West Nile virus (WNV). Invasive species like the tiger mosquito () and Asian bush mosquito () are rapidly spreading through Europe, posing a major threat as vectors for dengue, chikungunya (CHIKV), and Japanese encephalitis virus (JEV). These mosquitoes share a similar ecological niche as larvae, but the carry-over effects of aquatic larval interactions to the terrestrial adult stage remain largely unknown and their medical relevance requires further investigation. This study examines the context dependency of larval interactions among , , and . The survival, development time, growth, and energetic storage were measured in different European populations within density-response (intraspecific) experiments and replacement (interspecific) experiments at 20 °C and 26 °C. Overall, was the weakest competitor, while competition between and varied with temperature. Adults emerging from this larval competition were infected as follows: with WNV, with CHIKV, and with JEV. While no JEV infection was observed, mosquitoes experiencing interspecific interactions during their larval stages exhibited higher infection rates and viral RNA titers for CHIKV and WNV. This increased susceptibility to viral infection after larval competition suggests a higher risk of arbovirus transmission in co-occurring populations.