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Vespula wasps in New Zealand

German and common wasps (Vespula species) are social wasps that, since being introduced into New Zealand have spread throughout the country and during the "wasp season" there numbers are so high that they are a pest of urban, rural, and natural ecosystems.
Common wasps [Vespula vulgaris]

Common wasps [Vespula vulgaris]

Social wasps are those species that construct a nest (colony) in which a caste system develops; typically with a queen laying eggs and ‘workers’ taking care of the developing larvae, foraging for resources, and nest defence. Other insects with complex social systems include ants and some bees (which are both closely related to social wasps), and also termites.

New Zealand has the highest densities of these wasps in the world. In beech forest with honeydew, the biomass of social wasps (about 1100 g/ha/yr) is greater than that of all the native birds, upseting the ecological balance in native ecosystems. .

They can spoil peoples’ enjoyment of the outdoors, as well posing a health risk; affect the profitability and safety of industries such as beekeeping, horticulture, forestry and tourism. 

Our Aims

  • Provide up-to-date and authoritative information on Vespula wasps in New Zealand;
  • Enhance communication between regional and national biosecurity authorities, scientists, and the public.

10 Facts about Wasps

  1. The German wasp (Vespula germanica) was first found near Hamilton in 1945; the common wasp (Vespula vulgaris) has been in New Zealand since 1978
  2. The beech forests at the top of the South Island have the highest densities of wasps in the world; but wasps also occur in many other habitats across New Zealand
  3. On average, there are 12 nests per hectare in beech forests, that’s about 10,000 wasps per hectare!
  4. The highest number of nests recorded was 50–60 nests per hectare, the equivalent of 25–30 nests on a football field
  5. The largest nest ever found was four metres high and contained about four million cells
  6. There is a greater biomass of wasps (3.8kg/ha) in beech forest than all the native birds plus stoats and rodents put together
  7. The public voted wasps as “most disliked wildlife” (along with rats), because they spoil enjoyment of outdoor recreational activities
  8. Wasps destroy or seriously damage 8–9% of honeybee hives in New Zealand each year
  9. Wasps affect native foodwebs, and negatively affect the behaviour of native birds
  10. The predation rate of wasps on some native invertebrates is so high that the probability of their populations surviving through the wasp season is virtually nil

Arrival in New Zealand

There are no native social wasps in New Zealand – a very unusual situation compared with other parts of the world. However, there are four introduced species of social wasps established: two introduced species of paper wasps (Polistes) and two Vespula species.

The German wasp (Vespula germanica) is native to Europe and northern Africa. It was first found at an air force base near Hamilton, in 1945, and it has been suggested that hibernating queens arrived in New Zealand in crates of aircraft parts from Europe after the Second World War. Although considerable efforts were made to eradicate nests, German wasps spread very quickly, and within a few years were found in most of the North Island and parts of the upper South Island.

The common wasp (V. vulgaris) is native to Europe and parts of Asia (e.g. Pakistan and northern China). This species has also become introduced in Australia and, most recently, Argentina. Single specimens of the common wasp were recorded in New Zealand in 1921 and 1945 but these apparently did not establish. The common wasp was confirmed as established in Dunedin in 1983, although, examination of museum specimens showed that queens had been collected from Wellington as early as 1978. It rapidly spread throughout New Zealand and almost completely displaced the German wasp from beech forests in the upper South Island because of its superior competitiveness.

In general, wasp populations are large in New Zealand because of the mild climate, lack of natural enemies, and very abundant food sources (especially honeydew). However, recent reviews of invasive invertebrates continually point to social insects as one of the top problems around the world because of their high level of ‘ecological plasticity’ (i.e. flexibility to adapt and utilise resources). Factors such as nest size and longevity, a very wide diet range, feeding at different trophic levels, and ability to reach very high densities, all contribute to the successful invasion of social wasps.

Both the German and common wasp are now widespread throughout New Zealand. In some habitats, they can be some of the most common insects encountered. As a result, wasps have had detrimental impacts on native ecosystems, and human health, cause economic losses for beekeepers, and disrupt recreational activities.

Social wasps are pests in many temperate regions of the world. Consequently, a sizeable amount of research effort has been focused on developing control strategies. However, despite these efforts, wasps continue to be a major problem.

Award-winning wasp bait now available

Merchento has launched WWF Conservation Innovation Award winning Vespex®, a significant advance in wasp control. 

Find out more about  Vespex®  » 

 

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