Nelson cave spider  (Spelungula cavernicola)

Classified as Data Deficient (DD) on the IUCN Red List 2006.

As New Zealand’s largest spider, with an enormous 13 cm leg-span, this species is a startling sight in the limestone caves of the Nelson region where it lives (2) (3). These long-legged spiders are a mottled light brown colour and have very long claws on the first two pairs of legs (2) (4). Extremely rare, the Nelson cave spider is New Zealand's only protected species of spider (3).

Known only from a few limestone caves in northwest Nelson, New Zealand (2).

Found in limestone caves, mainly in complete darkness, usually within 10 to 20 m of the cave entrance, but sometimes much deeper (2).

These sizeable spiders are hunters that feed on cave weta (Gymnoplectron spp.), large grasshopper-like insects (4). Secured to the wall or ceiling via a drag line, the spider locates its prey and then drops down on top of it, before whisking it away in its grasp (4).

The Nelson cave spider produces large, almost spherical egg sacs that it suspends from the cave ceiling on silk threads (2) (4). Apparently long-lived, these spiders take three to five years to reach mature size, and have a low reproductive rate (5).

Although classified as Data Deficient (DD) on the IUCN Red List 2006 due to a lack of sufficient information, this spider is believed to be critically endangered and facing a high risk of extinction in the wild (6). The population size is estimated to number fewer than 250 mature individuals (6), and its rarity and restricted habitat mean that the Nelson cave spider occupies an extremely precarious existence (4). No major threats are known, but minor possible threats include rats, cave usage and disturbance, and the collection of egg sacs by cave visitors (2).

The Nelson cave spider is New Zealand’s only spider legally protected by the Wildlife Act 1953 (3).

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

For more information on the Nelson cave spider see:

• McGuinness, C.A. (2001) The conservation requirements of New Zealand’s nationally threatened invertebrates. Threatened Species Occasional Publication 20. New Zealand Department of Conservation, New Zealand. Available at:
  http://www.doc.govt.nz/publications/conservation/native-animals/invertebrates/conservation-requirements-of-threatened-invertebrates/
• Museum of New Zealand:
  http://www.tepapa.govt.nz/TePapa/English/CollectionsAndResearch/Collections/InsectsSpidersAndSimilar/Spiders/Spiders_Web/What/Nelsoncave.htm