Introduced wasps consume a very large share of New Zealand beech forest honeydew and outcompete native species for it.
Introduced Vespula wasps reach extraordinary densities in New Zealand beech forest — among the highest recorded anywhere — and studies have shown they remove the great majority of standing honeydew crop through much of the season. The effect on native birds and invertebrates that depend on the same resource is well documented and is the basis of large-scale wasp control programmes.
What this does not claim: This does not claim honey bees are harmed more than native species, nor that wasps are the only pressure on beech forest. Predation of native invertebrates by the same wasps is a separate and equally serious issue.
- Assessment Report on Pollinators, Pollination and Food Production — Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) (2016) · Systematic review Link