11 February 2011

Goniaea opomaloides - Mimetic Gumleaf Grasshopper

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Mimetic Gumleaf Grasshopper - Goniaea opomaloides

Goniaea is a small genus (less than 10 species) of Gumleaf Grasshoppers and belongs to the large Acrididae grasshopper family. There are at least 2 species in the Esperance region including this one, plus another a little further north. These two are easily separated from this species by their strongly arched pronotum (the upper shield between the head and abdomen), whereas Goniaea opomaloides is relatively flat. For details of Goniaea vocans the similar local Gumleaf Grasshopper, see post under that name labelled ‘Insects - Grasshopper - Gumleaf ' in the lower right-hand column.

Locally Goniaea opomaloides can also be confused with Peakesia brunnea the Grey Peakesia, but the paraglossae (the projection below the chin) is peg-like in that species and not chisel shaped as with the Mimetic Gumleaf Grasshopper. For details of Peakesia brunnea a similar local Grasshopper, see post under that name labelled ‘Insects - Grasshopper – Grey Peakesia’ in the lower right-hand column.

With this Gumleaf species, there is a large size difference between sexes with females growing to 4.5 cm (nearly 2”)  and males to only 3 cm (little over 1”) in length (Individuals shown above are female). Although not overly common, these grasshoppers can be found under Acacia and Eucalyptus spp. and once seen are relatively easy to approach, relying on their effective cryptic colouration to remain hidden. They are recorded across the southern part of Australia from Geraldton WA to Rockhampton Qld.

Further reading:
A Guide to Australian Grasshoppers and Locusts by Rentz, Lewis, Su and Upton.