28 June 2010

Western Coastal Pyrgomorph - Monistria latevittata

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Western Coastal Pyrgomorph - Monistria latevittata

Monistria latevittata belongs to the Pyrgomorphidae family and locally would be the most common of these unusual grasshoppers. Although widespread, they are not often encountered, probably because they are not particularly active, slowly moving about and relying on their cryptic coloration for their defence, however they are effective jumpers if required.

This species prefers sandy regions with heathland vegetation upon which it feeds and is known to occur from the north of Israelite Bay (east of Esperance) to the north of Perth, but excluding the more forested SW corner of the State. It differs from other Monistria species by being a light grey or brown with small orange spots. Monistria maculicornis is similar, but has a distinctive orange instead of a grey, brown coloration. Monistria discrepans is also grey, but with larger orange spots and Monistria consobrina has no facial white stripe. There are other differences, but these are less obvious.

A characteristic of Pyrgomorphs is the males are much smaller than the females and are often found riding jockey style on their backs. This does not mean they are currently mating, but the male taking up the mating position to stop other males from mating with her. Most of these grasshoppers have tiny wings that are not capable of flight, but in all populations a small percentage do have fully developed wings that are flight capable. Probably this ensures some individuals can escape a catastrophe (fire, flood, etc), or permit the mixing of genes with other sedentary colonies.

The females are around 3 cm (little over 1”) in head/body length and can be encountered at most times of the year. Both males and females have concealed, small bright red wings (remains of inner wings) that are fluttered with the outer ones as a scare tactic to deter predators.

My thanks to Dr David Rentz for identification.