Identification & surveillance
Invasive species are a major threat to the New Zealand environment. More than 2000 species of invasive invertebrates are already established in New Zealand . Some of these, such as Vespula wasps, have become abundant invaders that threaten our native ecosystems. New invasive invertebrates are continually arriving.
The volume of international trade and travel is such that our borders cannot be made totally secure against tiny invaders such as insects and spiders. Early detection of establishing populations is therefore important as the next line of defence.
Research into generalised surveillance techniques was started in recognition of a gap in biosecurity surveillance for invasive invertebrates, which is usually targeted at specific unwanted pests such as Asian gypsy moth, Mediterranean fruit fly, and Asian tiger mosquito. There is very little generalised surveying of invertebrates in high risk environments, so the primary source of information on the establishment of new invertebrate species is often public observation.
Identification
Identification keys: |
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Key to the ants of New Zealand |
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Key to the mosquitoes of New Zealand |
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What is this bug? - A guide to common invertebrates of New Zealand |
Surveillance
When a new species invades a country, there is usually a lag period of months or years between initial establishment and subsequent population explosion and spread. If new organisms can be detected during this early “sleeping” stage, there are more options available for management and a greater potential for eradication. As most invasive insects spread globally and nationally on human transportation networks, it is sensible to conclude establishing populations will often be found near urban areas.
Invertebrate sampling method
As part of our research into these urban “sleepers,” we began trialling a variety of trapping techniques in urban areas to compare the relative efficiency of various sampling methods. Many of the following comments apply to monitoring invertebrates for a whole range of purposes, so we have deliberately kept our discussion on the relative merits of each technique as general as possible. The huge diversity of invertebrates and their range of lifestyles mean no single trapping technique will effectively cover all types of invertebrates. Similarly, (depending on the purpose of the study being conducted and the type of data required) various traps can have different advantages for sampling the same invertebrate taxa.
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| Malaise traps | Mini-Malaise traps | Window traps | Sticky traps | Pitfall traps | U.V. light traps |
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| Flat ant traps | Baited ant pottles | Spurr wasp traps | Ground bottle traps | Yellow pan traps | Beating |