Landcare Research - Manaaki Whenua

Landcare-Research -Manaaki Whenua

New Zealand giant stag beetle

Pare - New Zealand giant stag beetle

Pare - New Zealand giant stag beetle

English name: New Zealand giant stag beetle, Helms' stag beetle

Scientific name: Geodorcus helmsi (Sharp)
order = Coleoptera; family = Lucanidae

  • is found only on Te Waipounamu / South Island, Rakiura / Stewart Island, and adjacent tītī (muttonbird) islands;
  • is a large, flightless beetle;
  • males are recognisable by enormous mandibles (jaws) as depicted here; in females the mandibles are small and inconspicuous;
  • stays under logs and stones in damp forests during the day;
  • emerges at night to feed on sap exuding from tree trunks;
  • grubs are large and cream-coloured, live in peaty soil, and feed on rotting plant material;
  • adults walk very slowly and cannot fly, so they are particularly vulnerable to predation by introduced rats and mice.

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