Wasp Impacts - Research
Landcare Research have concentrated on measuring the impact common (Vespula vulgaris) and German (Vespula germanica) wasps have on the honeydew beech forest in New Zealand. Very little work has been carried out on the impact paper wasps are having in New Zealand. See video of wasp taking honeydew (bandits 1) |
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Honeydew is produced by a native scale insect. The insect inserts its mouth-parts into the trunk of the beech tree to siphon the sap. The excess sap, modified by the scale insect, forms a sugary droplet at the end of a waxy anal filament. |
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Key Points
- At the peak of the wasp season wasps in honeydew beech forests have an average biomass of about 3.8 kg per hectare — 10 000 workers per hectare.
- The behaviour of at least three species of native bird is affected by this reduction in honeydew, but it is unknown if this affects the survival or reproductive success of these birds.
- The predation rate of wasps on some invertebrate prey species is so high that the probability of an individual surviving through the wasp season is virtually nil. Hence wasps probably reduce or eradicate populations of some invertebrates. Wasp abundance needs to be reduced by 80-90% to conserve some native invertebrate species.
- Wasps could also affect nutrient cycling in the honeydew beech forest community by reducing the flow of carbon to micro-organisms in the phyllosphere and the soil, ultimately this could affect soil solution chemistry.
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Wasp numbers |
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Impact on birds |
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Impact on invertebrates |