Post-invasion evolution of the western corn rootworm in Europe

Overview

Results

The team

Related information

So what's the problem?

The chrysomelid Diabrotica virgifera virgifera has become a serious pest of maize since it successfully invaded the USA and Europe. As D. v. virgifera has been introduced multiple times, several disparate populations of D. v. virgifera are known to exist in Europe. Thereafter, D. v. virgifera represents a good model organism to study the adaptation and characteristics associated with successful invasions.

Studies on environmentally-induced phenotypic differences among invading, non-invading or source populations from the area of origin may help to understand the role of phenotypic plasticity and local adaptations in this successful invasion. Variability of phenotypic traits, such as body size, may be used as indicators of genetic diversity, which is likely to be lower for invading populations owing to genetic bottlenecks than for the source populations. It may also reflect genetic changes due to the selection pressure from the new environment on the insect.

What is this project doing?

Comparison of the expectedly low variation of phenotypic traits and / or fitness of disparately invading populations of D. v. virgifera with poor genetic variability (Europe) with the phenotypic traits and fitness of D. v. virgifera with higher genetic variability (USA, potentially also Mexico)
Analyses of the effect of a hybridisation (crossing, crossbreeding) of bottlenecked and inbreeded populations (Europe) on the increase or non-increase in their fitness and thus invasion success (through increasing their genetic variability).

Within a 4-year multi-institutional research project, CABI was, in collaboration with INRA, Sophia Antipolis, France, responsible to compare invasive European strains to a potential source population. Furthermore, pure wild European strains of low genetic diversity were compared to an artificially crossed strain from two disparate European populations that will soon also naturally overlap in their distribution areas and cross, i.e. beetles from the Italy and from Central and South Eastern Europe. Life history traits of D. v. virgifera potentially important for invasiveness, like sex ratio, larval and adult longevity, egg viability, adult body size (elytra length and width), weight, flight activity as well as fecundity were examined with all of these crossed strains, pure European strains, an USA Pennsylvanian strain, and a Mexican strain in laboratory.

Results so far

So far, the large amount of fitness data of different D. v. virgifera strains has been finalised. In particular the fitness data has been analyzed with regard to their possible effects on the population growth rates and thus increasing problems with this invader in Europe.

Project Executive

Ulrich Kuhlmann

Address: Rue des Grillons 1, CH-2800 Delemont, Switzerland

Tel: +41 (0)32 421 4882

Email: u.kuhlmann@cabi.org

Project Manager

Stefan Toepfer

Address: c/o Plant Protection Directorate Rarosi ut, 110 H - 6800 Hodmezovasarhely, Hungary

Tel: +36 62 535740

Email: s.toepfer@cabi.org

Project Team

Tim Haye

Address: Rue des Grillons 1, CH-2800 Delemont, Switzerland

Tel: +41 (0)32 4214883

Email: t.haye@cabi.org

Hongmei Li

Address: C/o CAAS-CABI Project Office, C/o Internal Post Box 56, Chinese Academy of Agricultural Sciences, 12 Zhongguancun Nandajie, Beijing 100081, China

Tel: +86 (0)10 6289 8289

Email: h.li@cabi.org

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