Multiple transatlantic introductions of the western corn rootworm

Area of Science:

• Agricultural Entomology
• Invasive Species Biology
• Population Genetics

Background:

• The western corn rootworm (Diabrotica virgifera virgifera) is a major pest of corn in North America.
• Its introduction into Europe poses a significant threat to European agriculture.
• Previous understanding suggested a single introduction point in Central Europe leading to subsequent spread.

Purpose of the Study:

• To investigate the origin and introduction pathways of the western corn rootworm in Europe.
• To determine if European infestations originated solely from Central European populations.
• To analyze the genetic diversity of the pest to infer introduction events.

Main Methods:

• Utilized model-based Bayesian analyses.
• Examined genetic variability within western corn rootworm populations.
• Compared genetic data to infer population structure and historical introductions.

Main Results:

• The study refutes the hypothesis of a single introduction point in Central Europe.
• Evidence indicates at least three independent introductions of the western corn rootworm from North America.
• These introductions occurred within the last two decades.

Conclusions:

• European populations of the western corn rootworm are not the result of a single introduction event.
• Multiple, independent transatlantic introductions have facilitated the pest's spread.
• Further research is needed to understand factors enabling increased introductions.