# Extended time to maturity in Anopheles coluzzii: Implications of late egg hatch for vector control and transgene fitness

## TL;DR

Late-hatching Anopheles coluzzii mosquitoes show no fitness costs and could be better for transporting eggs to remote areas for population control.

## Contribution

Late-hatching Anopheles coluzzii lines show no fitness costs and are viable for mass rearing and genetic interventions.

## Key findings

- Late-hatching lines showed increased fecundity and survival compared to early-hatching lines.
- No negative effects of selection on fecundity or adult survival were detected in late-hatching lines.
- Late-hatching lines are a viable alternative to the Mopti strain for mosquito mass releases.

## Abstract

Maintaining fitness is an important consideration when mosquitoes are mass‐reared for the deployment of genetic interventions that are designed to suppress populations because released mosquitoes need to compete with wild‐type mosquitoes. Late‐hatching mosquitoes are more suitable for transportation to remote field sites. Here, we investigated the fitness of late‐hatching phenotypes in Anopheles coluzzii. Selected lines of the VK strain (from Burkina Faso) were created through bidirectional selection for early and late hatching, over 20 generations. These were compared with each other and the established Mopti reference strain from Mali, reared in the lab for >16 years. Significant differences in life‐history traits were found between Mopti and VK strains but few differences were found between the selected VK lines. Considering that late‐hatching VK lines showed no evidence of fitness costs, our results suggest that the late selected VK lines, which start hatching after 4 days, are an alternative option for egg shipment for mass mosquito releases over the well‐established Mopti that hatches within 2 days and has lower adult survival.

The fitness of Anopheles coluzzii mosquito lines (VK strain) selected for early and late egg hatching was compared with each other and a reference strain (Mopti).There was an observed increase in fitness in fecundity and survival among the late‐hatching lines, but no negative effects of selection on fecundity and adult survival were detected.This study informs that selected late‐hatching mosquito lines could serve as suitable starting lines for developing sterile or genetically modified lines intended for mosquito mass releases.

The fitness of Anopheles coluzzii mosquito lines (VK strain) selected for early and late egg hatching was compared with each other and a reference strain (Mopti).

There was an observed increase in fitness in fecundity and survival among the late‐hatching lines, but no negative effects of selection on fecundity and adult survival were detected.

This study informs that selected late‐hatching mosquito lines could serve as suitable starting lines for developing sterile or genetically modified lines intended for mosquito mass releases.