Stick insects (Phasmatodea)
Stick insects are large insects famous for their close resemblance to the foliage on which they feed. Stick insects are surprisingly common in New Zealand and can be found from coastal vegetation to the high-alpine zone, although many species are poorly known because of their cryptic appearance and nocturnal habits.
Predation by wasps and possums is a threat in some areas of the country.
The New Zealand stick insect fauna contains 21 valid species in eight genera, but much taxonomic work remains to be done. Recent fieldwork and data analyses have revealed the presence of undescribed species, particularly in the South Island. Furthermore, several described species are of dubious validity. Current taxonomic research includes a large amount of collecting throughout New Zealand and all major offshore islands. Generic and species boundaries are being determined using both morphological and molecular genetic characters.
New Zealand insects and other invertebrates offer ideal case studies for testing a wide variety of evolutionary scenarios and hypotheses. Molecular systematic methods are being used to determine species boundaries in taxonomically problematic invertebrate groups, study the impact of environmental change on species radiations, and determine the origins and evolution of the New Zealand terrestrial invertebrate biota.