# Reproductive Trade-Offs in Culex pipiens: Effects of CYV Infection and Delayed Mating

## TL;DR

This study explores how a mosquito-specific virus affects reproduction in two Culex pipiens species, finding that age, not the virus, mainly influences egg production.

## Contribution

The study reveals that age, rather than CYV infection, significantly impacts reproductive success in Cx. pipiens biotype molestus.

## Key findings

- CYV infection had minimal impact on mosquito reproduction in both Cx. pipiens biotype molestus and Cx. pipiens quinquefasciatus.
- Older Cx. pipiens biotype molestus mosquitoes laid fewer eggs regardless of blood meal availability.
- Age affected reproductive success in Cx. pipiens biotype molestus but not in Cx. pipiens quinquefasciatus.

## Abstract

Mosquitoes are important carriers of viruses that cause diseases like West Nile virus and Zika virus, and controlling their reproduction can help reduce the spread of these diseases. One potential approach to controlling mosquito populations is using viruses that specifically affect mosquitoes, known as insect-specific viruses. In this study, we examined the impact of the Culex Y virus on the reproduction of two mosquito species: Culex pipiens biotype molestus and Culex pipiens quinquefasciatus. We also compared these mosquitoes to better understand how different species respond to the virus. Our results showed that the virus did not have a major impact on mosquito reproduction, although the age of the mosquitoes did affect their ability to produce eggs as well as their general oviposition behavior. Older Cx. pipiens biotype molestus mosquitoes laid fewer eggs, even when they were given a blood meal. These findings are important for understanding influential factors for mosquito reproduction and can help improve strategies for controlling mosquito populations without harming other animals or humans.

Arbovirus control strategies often target vector reproductive dynamics, with insect-specific viruses (ISVs) like Culex Y virus (CYV) offering potential as eco-friendly approaches by influencing mosquito reproduction without affecting humans or animals. This study investigated the interplay between autogeny, anautogeny, nutrient availability, and viral infection and their effect on reproductive success in Culex pipiens biotype molestus and Culex pipiens quinquefasciatus. CYV infection had a minimal impact on mosquito reproductive parameters, even after a five-day incubation period. Autogeny enabled Cx. pipiens biotype molestus to produce eggs without blood meals, yet older females (3–5 days post-emergence) showed reduced reproductive success unrelated to nutrient deficiency, as blood-feeding did not restore their egg production. These findings demonstrate that age affects reproductive success in Cx. pipiens biotype molestus but not in Cx. pipiens quinquefasciatus and suggest that CYV has negligible direct effects on mosquito reproduction. This work enhances our understanding of ISV biology and vector ecology, supporting the development of innovative, sustainable arbovirus-control strategies.