Topic: The influence of the microbiome on the successful invasion of a global pest
Dates: 1 November 2024 – 31 October 2027
CBGP supervisors: M. Javal & E. Frago
University: University of Montpellier

Insects have developed a wide variety of relationships with microorganisms. Herbivorous species, in particular, often rely on their gut microbiota to obtain certain essential nutrients, adapt to abiotic conditions, defend themselves against natural enemies, or detoxify insecticides. Furthermore, the composition of their digestive bacterial community can vary, sometimes over very short time scales, in response to a new environment or a new host – situations that may be encountered during biological invasions.

This project will focus on the study of Spodoptera frugiperda, a moth native to the Americas that is highly polyphagous and causes significant damage to food crops. It is capable of rapidly developing resistance to control methods, which makes its management particularly challenging. The microbiota of S. frugiperda can vary depending on the host plant on which the larvae are found or on agricultural practices. Nevertheless, the role of microbial symbioses in this species remains poorly understood.

This thesis aims to investigate whether changes in the microbiota, such as those previously described in S. frugiperda, occur during the invasion and are associated with increased tolerance to environmental stresses in the insect. We will also seek to describe the reciprocal interactions between the composition and diversity of the gut microbiota and resistance to abiotic stresses such as extreme temperatures and exposure to insecticides.