Evolution of sex allocation strategies in the spidermite Tetranychus urticae, a major crop pest – EVOLSEXALLLOC
Evolution of sexual allocaton and use of sexual conflicts sexuels again a major pest
We want to understand the evolution of sex ratio in Tetranychus urticae and use the conflicts among sexes in situation of mixing or in presence of the bacteria Wolbachia to decrease the number of females and hence reduce the population growth rate of this important pest.
Undetand sex ratio and use this knowledge to manage Tetranychus urticae
Sex ratio (number of males / number of females) of spider mites is in general 1:3. We want to understand it and increase it to 1:1, without using pestides, to which spider mites are often resistant. As population growth is usually due to females, our project should lead to decrease the growth of populations of this major pest of crops.
Tasks 1 to 3 aims at understanding the genetics and evolution of sex allocation, sex ratio, sexual conflicts and mating systems in our particular biological system,. Task 4 focuses on the effects of the bacteria Wolbachia. Task 5 is a modelling study integrating previous results. Finally, Task 6 is a greenhouse experiment aimed at using this knowledge to manipulate sex ratio so as to use all results to manipulate poupulations sex ratio of spider mites, and hence to improve biocontrol. France will coordinate Tasks 1, 2 and 5;.
Major results of the project on 9/9/2013: the first male fertlises 80% (and not 100%) of females, which are fertilised at 20% by the second male. Males, which prefer virgin females, have thus an interest in mating, including with non virgin females. We still do not understand why females accept to remate. We have otherwise started new experimental populations.
We are still asking why females remate, and will make controled crossings between experimental populations to understand how are determined sex ratio and its plasticity
Nothing since February2013.
Using a combination of experimental evolution, genetics and modelling, we aim at deciphering the short term and long term mechanisms of sex allocation and sexual conflicts in a haplodiploid species, the spider mite Tetranychus urticae. We will then use this knowledge to design management strategies to reduce population growth rate of this species, which is a major Arthropod pest of c.a. 1100 plant species, in particular in indoor cultivation (e.g., greenhouses). Thus the general framework of the project is fundamental research, but it should lead to better and environmentally-friendly management of a major crop pest.
Our work programme is organised as six main tasks. Tasks 1 to 3 aims at understanding the genetics and evolution of sex allocation, sex ratio, sexual conflicts and mating system in our model biological system, using laboratory populations uninfected by the bacteria Wolbachia. Task 4 focuses on the effects of Wolbachia on sex ratio and sex allocation. Task 5 is a modelling study integrating previous results. Finally, Task 6 is a greenhouse experiment aimed at manipulating sex ratio so as to improve biocontrol. Partner 1 will coordinate Tasks 1, 2 and 5 while partner 2 will coordinate Tasks 3, 4 and 6.
Project coordination
Isabelle OLIVIERI (Institut des Sciences de l'Evolution) – Isabelle.Olivieri@univ-montp2.fr
The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.
Partner
ISEM Institut des Sciences de l'Evolution
LISBON Centro de Biologia Ambiental, Universidad de Lisboa
Help of the ANR 264,185 euros
Beginning and duration of the scientific project:
February 2013
- 36 Months
