Modeling population dynamics based on experimental trials with genetically modified (RIDL) mosquitoes

TL;DR

This paper develops an ecological stochastic model to analyze the population dynamics of genetically modified mosquitoes used for disease control, highlighting critical biological knowledge gaps and assessing intervention outcomes.

Contribution

It introduces a new ecological model compatible with 2016 data, linking mosquito populations, food availability, and genetic modifications to evaluate control strategies.

Findings

Hybridization levels depend on intervention parameters.

Population recovery times vary with intervention duration.

Non-lethal genes are unlikely to be naturally eliminated.

Abstract

Recently, the RIDL-SIT technology has been field-tested for control of Aedes aegypti. The technique consists of releasing genetically modified mosquitoes carrying a "lethal gene". In 2016 the World Health Organisation (WHO) and the Pan-American Health Organization (PAHO) recommend to their constituent countries to test the new technologies proposed to control Aedes aegypti populations. However, issues concerning effectiveness and ecological impact have not been thoroughly studied so far. In order to study these issues, we develop an ecological model compatible with the information available as of 2016. It presents an interdependent dynamics of mosquito populations and food in an homogeneous setting. Mosquito populations are described in an stochastic compartmental setup in terms of reaction norms depending on the available food in the environment. The development of the model allows us to indicate some critical biological knowledge that is missing and could (should) be produced. Hybridisation levels, release numbers during and after intervention and population recovery time after the intervention as a function of intervention duration and target are calculated under different hypotheses with regard to the fitness of hybrids and compared with two field studies of actual interventions. The minimal model should serve as a basis for detailed models when the necessary information to construct them is produced. For the time being, the model shows that nature will not clean the non-lethal introgressed genes.