Sunday, 13 February 2011

A Couple of Big Fellows

A wander in the rainforest after dark can reveal creatures you would not normally se during the day. Meet a Raspy Cricket, Chauliogryllacris sp., family Gryllacrididae. This large insect is soft-bodied and would desiccate if exposed to the drying condition of sunlight and wind during the day. It's massive head conceals mostly muscle that power the mandibles. Although it can give a painful bite, it is an omnivore and feeds on a range of foods ranging from other insects to fruits and seeds.

The mandibles are used primarily to dig into rotting wood where it makes a burrow and covers the entrance with silk fibres that it produces form its mouthparts. This is a characteristic of the family Gryllacrididae. Nymphs as well as adults produce silk.

the white spot in the centre of the head is the median ocellus. The two small yellow spots just above the first antennal segment are lateral ocelli. The function of these "eyes" varies from one group of invertebrates to another but here they may be involved with a homing behaviour that is similar to that displayed by ants. Raspy crickets "take a picture" of their surrounds before they move out for a night's marauding. This enables them to return to their burrow and not have to expend the energy to construct another.

Chauliogryllacris is a big cricket. The body of this female measured 50 mm. the antennae were extraordinarily long, measuring 165 mm.


The Queensland Palm Katydid, Segestidea queenslandica, has been featured several times in this blog. This is an unusual dark form. It is big with the body measuring some 90 mm from there head to the tip of the wings. This species is facultatively parthenogenetic, that is unmated females can produce eggs that hatch. The hatchlings are always females. Males in this species are rare but this year on one night three were heard along the Kennedy highway near Kuranda. They were singing from Wait-a-while vines (Calamus sp.) high in the trees. This was the first time I had heard this species even though I have encountered dozens of examples over the years. Soon I'll present a recording of the song of this katydid.

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