Australian plague locust

Description

The Australian plague locust (Chortoicetes terminifera) is a native Australian insect in the family Acrididae, and a significant agricultural pest. Adult Australian plague locusts range in size from 20 to 45 mm in length, and the colour varies from brown to green. In profile, the head is higher than the thorax, and the thorax has an X-shaped mark. The legs have a reddish shank and the wings are clear other than for a dark spot on the periphery. The locusts occur naturally in far northwestern New South Wales and the adjoining areas of Queensland and South Australia, as well as Western Australia. From these areas, the locusts can expand from time to time to be found in the agricultural areas of South Australia, New South Wales, including the Riverina, and Victoria. The locust can be found in a variety of grassland and open wooded habitats across the inland areas of the Australian mainland. Upper-level winds may occasionally carry locusts to coastal areas of the mainland and northern Tasmania and may establish populations in the eastern valleys of the Great Dividing Range; these populations usually fail to establish themselves for more than a few generations. Climatic change is projected to influence spatial patterns of pest outbreaks, as climate change is a primary limiting factor for insect dispersal. The most commercially important locust species in Australia is the Australian plague locust, Chortoicetes terminifera. Invasions wreak havoc on agricultural crops and pastures on a massive scale. Adult locusts feeding on green shoots that follow rain within 24 to 48 hours in warmer months will mature and lay eggs within 5 to 7 days of a rain event. Using their ovipositors to drill a hole, locusts lay their eggs in the soil in a pod. Pods contain around 30 to 50 eggs and locusts lay two or three pods, 5 to 10 days apart. Egglaying often happens en masse, with as many as a million laid in a hectare of suitable soil. In good conditions (i.e. warm and moist), eggs take around two weeks to develop. After hatching, the nymphs take around 20-25 days to complete development in mid-summer. The locust has five instars, with the wings becoming more prominent with each moult.