Many crickets live in burrows during the day. Raspy crickets (Family Gryllacrididae) construct shelters with material bound together by silk or maintain silk-lined burrows. These crickets often leave their shelters at night to forage. During the day they seal the entrance shut with silk to avoid desiccation (drying out). True crickets (Family Gryllidae) may live in burrows, crevices in the soil, in logs or under leaf litter.
Katydids and tree crickets all belong to the family Tettigoniidae. The family is very large, containing approximately 1000 described species in Australia, with many more undescribed. Its members display a variety of habitat and dietary preferences. Katydids feed on pollen and nectar, vegetation, insects and invertebrates. The family is found throughout Australia.
Locusts and grasshoppers (Suborder Caelifera, Family Acrididae) are very common insects. However, locusts behave differently depending on their numbers. When numbers are low they act as individuals, in the same way as grasshoppers. But when large numbers are present they behave as a group or swarm, causing plagues.
Locusts such as the Australian Plague Locust (Chortoicetes terminifera), the Spur-throated Locust (Austracris guttulosa) and the Migratory Locust (Locusta migratoria migratoriodes) can form plagues that cause massive damage to agricultural crops. Locust plagues usually occur when the right rainfall conditions enable several generations to reproduce in large numbers. The Australian Plague Locust Commission conducts regular surveys and research to combat the outbreak of plagues.
Both locusts and grasshoppers feed on mainly grasses, but many other plants are also eaten. Both are eaten by a wide variety of animals and parasitised by mites, worms and other insects such as the wasps of the genus Scelio, which parasitise the eggs. In some parts of the world locusts are eaten by people.
Mole Crickets (Family Gryllotalpidae) are common in well-watered urban parks and gardens. Using their large forelegs, male mole crickets dig specially constructed burrows which act as amplifying 'horns'. These flightless males can be heard at dusk during the warmer months making a very loud, continuous call using their modified wings. The calls help the flying females locate the males for mating. Mole crickets are the only crickets where the females can also call (but not as loudly as the males).
Sand Gropers (Family Cylindrachetidae) are large burrowing orthopterans, mostly found in Western Australia. One species is an occasional pest of wheat crops. Both sexes are wingless and rarely emerge above ground.