Genus SigausHutton, 1897 Rank Species | ||
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Sigaus homerensis is a grashopper endemic to southern South Island of New Zealand. It is only known from Fiordland, in three isolated populations.
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Distribution and habitat
The distribution of S. homerensis is not known to overlap with that of any other grasshopper species and is known only from the Earl Mountains. Sigaus homerensis is only one of three known alpine grasshoppers that is found in Fiordland, the other species are Alpinacris tumidicauda and Sigaus takahe. Known sites of S. homerensis are regularly swept clear of tall plants by avalanches, making these areas more sparsely vegetated than the surrounding. Similar terrain and vegetation is found outside the known distribution, however, S. homerensis are not found in these areas. A possible explanation of this could be associated with avalanches, vegetation height and sunshine hours. This region receives high rainfall (about 8000 mm/year) coupled with the lowest sunshine hours in New Zealand (1400 to 1600 h/year). It appears that these small cleared areas are better for S. homerensis than avalanche-free areas with their taller vegetation. New Zealand Acrididae are diurnal sun-baskers and require basking surface to become active for the day S. homerensis prefer altitudes between 900–1,000 metres (3,000–3,300 ft), however, it can be found as low as 639 metres (2,096 ft) and as high as 1,257 metres (4,124 ft).
Species description
The wings on S. homerensis are micropterous (small wings) between 2–4 millimetres (0.079–0.157 in) making this species flightless like most of New Zealand grasshoppers. Male body length 19–21 millimetres (0.75–0.83 in); Female body length 28–38 millimetres (1.1–1.5 in).
Type information
Polymorphism
Two colour morphs are known for adults S. homerensis, 'Drab gold' and 'Dark blue-grey'. Approximately two-thirds of the adults S. homerensis are of the 'Drab Gold' colour morph.