Thrips of New Zealand
More than half of the 127 thrips species recorded from New Zealand have come from other countries. Many of these are now established here, although the single record of Idolothrips spectrum is presumably based on a wind-dispersed individual. This common Australian thrips is known to breed only on dead Eucalyptus leaves, and there is no evidence that any population has ever established in New Zealand. Thrips hawaiiensis is another species listed from New Zealand but for which there is no evidence of breeding. A single female of this species was reported in 1964 from Campbell Island, but this is an unlikely record for an insect that lives in tropical countries. In contrast, Thrips imaginis, the Australian Plague thrips that occurs in vast numbers in southeastern Australia, is presumably wind-dispersed to New Zealand from time to time, but apparently fails to establish large populations.
Introductions from Europe have been far more successful, including several grass thrips such as Aptinothrips, Chirothrips, and Limothrips. Similarly, various flower thrips associated particularly with Asteraceae are well established in New Zealand, including Tenothrips frici from southern Europe and Haplothrips kurdjumovi and H. leucanthemi from northern Europe. Many other of the adventive species are well-known as worldwide tramps, including Heliothrips, Hercinothrips, Frankliniella occidentalis, Pezothrips kellyanus, Thrips simplex and Thrips tabaci. Other species are shared only with Australia, and these may either have been introduced inadvertently, or possibly they are naturally wind-dispersed across the Tasman: Pseudanaphothrips achaetus, Karphothrips dugdalei, Cartomothrips manukae, Cartomothrips neboissi, Haplothrips salicorniae and Yarnkothrips kolourus. For a few species, their occurrence, even establishment, is more surprising, including Merothrips brunneus that presumably evolved somewhere in the Neotropics, and Stenchaetothrips martini that is presumably introduced from Asia along with its bamboo host-plant.