# The artificial meal SkitoSnack does not support reproduction in Culex pipiens (Diptera: Culicidae) mosquitoes

## TL;DR

The artificial meal SkitoSnack, which works for Aedes aegypti mosquitoes, fails to support reproduction in Culex pipiens mosquitoes, leading to reduced fertility and offspring viability.

## Contribution

This study is the first to evaluate SkitoSnack's effectiveness for Culex pipiens, revealing its limitations in supporting mosquito reproduction.

## Key findings

- SkitoSnack-fed Culex pipiens females showed high mortality and reduced fecundity, fertility, and egg-hatching rates.
- SkitoSnack-fed Culex pipiens females produced non-viable offspring, unlike those fed with animal blood.
- Aedes aegypti also showed reduced fecundity and fertility when fed SkitoSnack.

## Abstract

Mosquitoes are hematophagous insects. Obtaining fresh animal blood to maintain laboratory colonies, rear high numbers of mosquitoes, or blood-feed mosquitoes for experimental purposes, can be costly and imposes ethical concerns. Recently, the artificial meal SkitoSnack was developed to rear Aedes aegypti L. mosquitoes. This artificial diet is low-cost, can be easily prepared in the laboratory, and results in comparable life history traits to Ae. aegypti raised with animal blood. Here, we investigated if the SkitoSnack can be used to produce the next generation of Culex pipiens L. as a substitute for animal blood and assessed the effects on mosquito fitness. Female Cx. pipiens fed with SkitoSnack demonstrated high post-feeding mortality and lower fecundity, fertility, egg-laying rates, egg-hatching rates, and offspring emergence rates compared to those fed with vertebrate animal blood. In contrast, the longevity and body sizes of the offspring were not significantly different between the 2 feeding groups, suggesting that the first generation of SkitoSnack-reared mosquitoes had similar fitness to those raised from animal blood. Feeding a different generation of Cx. pipiens resulted in a similar loss of fitness in the SkitoSnack-fed females; however, these females were unable to produce viable offspring. In addition, we fed the SkitoSnack to Ae. aegypti, which also resulted in a significant reduction in fecundity and fertility. A significant loss of life and reproductive capacity was observed in SkitoSnack-fed Cx. pipiens, but more research is required to determine whether optimizing the current SkitoSnack formula can improve the fitness outcomes of fed females.