Invasive success and the evolution of enhanced weaponry

Submitted by editor on 26 May 2015.Get the paper!

The success of invasive plants is often attributed to the production of chemicals that are highly inhibitory against naïve neighbours at the introduced range (‘novel weapons hypothesis’). However, invasive populations could not only possess such novel weapons, but might also evolve their enhanced production. In our new paper “Invasive success and the evolution of enhanced weaponry”, we examined these two hypotheses with Impatiens glandulifera (Himalayan Balsam), which is an annual plant native to the Himalayas and highly invasive throughout Europe.

We studied the evolution of allelopathic ability in I. glandulifera by comparing the inhibitory effects of leaf extracts from native vs. invasive populations on the germination success of one of its most dominant neighbours, Urtica dioica.

Preparation of Impatiens glandulifera leaf extracts


Sinja Zieger counting the number of germinating Urtica dioica seeds treated with leaf extracts of Impatiens glandulifera from native or invasive origin

Our results provide support to the hypothesis that enhanced production of novel weapons might evolve at the invasive range and facilitate invasion success. This calls for biogeographical studies that will examine not only the novelty but also the evolution of allelopathy in invasive plants.

The authors through Michal Gruntman

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