Poor Knights weta  (Deinacrida fallai)

Classified as Vulnerable (VU) on the IUCN Red List 2006.

The Poor Knights weta is one of over 100 large, flightless insects belonging to the weta family (Stenopelmatidae), all of which are endemic to the New Zealand archipelago (2). Weta are one of the world’s most ancient groups of species alive today (3), and look somewhere between a cockroach and a cricket, with large legs (2). This sizeable species belongs to a subset known as giant weta (Deinacrida), which comprises some of the largest insects on Earth (2). The Poor Knights weta is pale brown with dark brown lower hind limbs, a line of black markings on its back and black stripes along the flanks (4).

Confined to the Poor Knights group of islands, New Zealand, after which it is named. Common on the two main islands, Tawhiti Rahi and Aorangi, and a faecal pellet confirmed to be from a species of giant weta has been found on Archway Island (4).

This species is primarily arboreal but also frequently ventures to the ground, where it lays its eggs (4).

During their life span of a little over two years, Poor Knights weta pass through 9 to 11 nymphal stages before reaching maturity (4) (5). Egg-laying can take place at any time of the year throughout the female’s adult life. Between 200 and 300 eggs per clutch are laid in the ground (4).

These nocturnal insects mainly feed on vegetation such as leaves, fruit and fungi, with invertebrates only forming a minor part of the diet (2) (4).

Although this giant weta is not thought to be declining in either abundance or distribution, its restricted range within the Poor Knights Islands leaves it in a highly vulnerable position. A range of native species (e.g. tuatara, lizards and birds) prey upon this weta, but do not appear to have a dramatic impact or threaten the species’ survival. However, any reintroduction of other predators, such as the native saddleback, could be extremely damaging, although there are no current plans to reintroduce such species. Accidental introduction of rodents could also decimate Poor Knights weta populations, and poses a serious potential threat to the species (4).

Poor Knights weta have been successfully bred in captivity at Wellington Zoo, providing a source of research and public education, a buffer against extinction, and potential stock for reintroductions into the wild to bolster population numbers (4) (5).

View information on this species at the UNEP World Conservation Monitoring Centre.

For more information on the Poor Knights weta see:

• Sherley, G.H. (1998) Threatened Weta Recovery Plan (Threatened Species Recovery Plan No. 25). Biodiversity Recovery Unit, Department for Conservation, Wellington, New Zealand. Available at:
  http://www.doc.govt.nz/upload/documents/science-and-technical/tsrp25.pdf