Invasive European Paper Wasp

outcompetING native species, European Paper Wasps can lead to a decrease in effective pollination, which have significant impacts on local plant populations and overall ecosystem health.

Native to southern Europe and North Africa, and temperate parts of Asia as far east as China, the European paper wasp, scientifically known as Polistes dominula, is believed to have arrived in South Africa as a stowaway, hidden in cargo on a ship.

The wasp was first recorded in Kuilsrivier in 2008 and has been a problem ever since.

Since the mid-1980s it has also been introduced to the cooler regions of New Zealand, Australia, and North and South America.

Legislation:
Under the National Environment Management: Biodiversity Act (NEMBA), the European paper wasp is designated as a Category 1b Invasive Alien Species, requiring management as part of an invasive species control plan.

Identification

The European paper wasp is a medium-sized wasp, 12-16mm in length, with bold black and yellow patterns. It constructs communal paper nests in trees, shrubs, and under roof eaves. These wasps emerge in the early summer, with their numbers increasing steadily well into autumn.

Life Cycle

These wasps have a lek-based mating system. Within colonies of European paper wasps, one queen generally mates with multiple males. The life cycle of Polistes dominula involves a process known as metamorphosis. The dominant females are the principal egg layers, while the subordinate females (“auxiliaries”) or workers primarily forage and do not lay eggs. This hierarchy is not permanent, though; when the queen is removed from the nest, the second-most dominant female takes over the role of the previous queen.

Impacts

Competition with Local Species

One of the primary impacts of the European paper wasp is its competition with local species for resources. These wasps are generalist predators and feed on a wide variety of insects. This puts them in direct competition with native predatory insects for food resources. In areas where the European paper wasp has become established, it can outcompete native species, leading to a decrease in their populations. This can have a cascading effect on the local ecosystem, potentially leading to a decrease in biodiversity.

Hazard to Humans

The European paper wasp also poses a significant hazard to humans. They are known to be more aggressive than native wasp species and can attack when they feel their nests are threatened. Their stings can be very painful and can cause allergic reactions in some individuals. In severe cases, these allergic reactions can be life-threatening. Furthermore, because these wasps are likely to build their nests near human environments, the likelihood of encounters and potential stings increases.

Disruption of Pollination

Another potential impact of the European paper wasp is the disruption of pollination. While these wasps do contribute to pollination, they are not as effective as many native pollinators. If they outcompete these native species, it could lead to a decrease in effective pollination, which could have significant impacts on local plant populations and overall ecosystem health.