The good news for South Africa is that these two invasive species are still contained in quite a small geographical range. In countries like New Zealand, where the population of especially the German wasp is dense and widespread, they are threatening endemic invertebrates such as caterpillars and orb web spiders. This suggests that these biocontrol agents could be used in the future to effectively control the invasive wasps – before their populations spread. The results are promising: all four of the agents proved able to infect and kill both invasive wasp species’ larvae. The agents in question occur naturally in South African soils. I selected a few agents I suspected would target these wasps without harming other insects. These are biological organisms that are used for pest control instead of, or alongside, chemicals. I learned this first hand while conducting research for my PhD: I was stung more than 40 times as I attempted to collect nest material and wasps to use in experiments evaluating their susceptibility to various biological control agents. Anyone who’s ever had a close encounter with the European paper wasp or the German wasp will know, they deliver a nasty sting. These invasive species are bad news for everything from biodiversity to agriculture and horticulture to viticulture. Both species are thought to have been introduced via air or sea cargo. Another, the Polistes dominula (European paper wasp), arrived in 2008. One such species, the Vespula germanica (German wasp), was introduced into the country in 1974.
South Africa is home to a number of invasive insect species.
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