Spur-throated locust (Austracris guttulosa)

Austracris guttulosa
Taxonomic classification
Suborder:	Caelifera
Family:	Acrididae
Subfamily:	Cyrtacanthacridinae
Genus:	Austracris
Scientific name
Austracris guttulosa (Walker, 1870)
Geography
Native countries:
Fiji Papua New Guinea Australia Tonga Indonesia New Caledonia Vanuatu Wallis and Futuna Timor-Leste
Pest status
Known pest

The spur-throated locust (Austracris guttulosa) is a large and notable grasshopper species found in Australia and New Zealand, easily recognized by the distinctive spur-shaped projection on its throat. Primarily a tropical species, it inhabits savannahs and grasslands, where it exhibits gregarious behavior and can form dense, mobile swarms during late autumn and winter. This polyphagous species feeds on a wide range of plants, including crops and pastures, and can undergo phase changes from solitary individuals to highly destructive swarms during population booms. Although less frequent and severe than other locust species, the spur-throated locust is an important agricultural pest in parts of Queensland, New South Wales, and Western Australia, capable of damaging both summer and winter crops.

Taxonomy

For full nomenclature and taxonomic details of this taxon, see Orthoptera Species File

Identification

The spur-throated locust is part of the subfamily Cyrtacanthacridinae which contains many of the world’s most notorious locusts. These grasshoppers are typically large-bodied, strong fliers, and capable of forming swarms under favorable environmental conditions. Their ability to switch between solitary and gregarious phases—known as phase polyphenism—underlies their capacity for sudden population outbreaks. Other prominent species include the desert locust (Schistocerca gregaria), the brown locust (Locustana pardalina), and the migratory locust (Locusta migratoria), though several other Cyrtacanthacridinae species exhibit migratory or outbreak-prone behavior. These insects are adapted to semi-arid and savanna environments across Africa, Asia, and Australia, where periodic rainfall can trigger rapid breeding and swarm development.

Identification details

Nymphs and adults of A. guttulosa are characterized by a prominent spur between their front legs. Newly hatched nymphs are bright green, later developing a dark stripe along the middle of the back, and often shifting from green to pale yellow as they mature. Adults are large and slender, typically pale brown with a long straw-colored stripe, white markings, and darker patterns on the thorax. Their hind wings are clear with a slight bluish tinge, and the hind leg shanks range from straw to mauve, bearing two rows of white spines tipped in black. Females measure 6.0–8.0 cm and males 4.0–6.5 cm.

Featured resource

• 
  Locusts of Australia
• 
  Managing Locusts in Queensland

Identification resources

Title	Author(s)	Year	Geographic purview	URL
How to identify locusts		2021		View URL
Managing locusts in Queensland		2022		View URL
Australian plague locust online learning module		2022		View URL
Agriculture Victoria Australian plague locust identification, biology and behaviour		2022		View URL
APLC locust and grasshopper identification guide	Australian Plague Locust Commission
Locusts of Australia	Queensland Department of Agriculture and Fisheries	2020		View URL

Distribution

The spur-throated locust is found across northern Australia, Papua New Guinea, Indonesia, and the Philippines. In Australia, its primary breeding grounds are the monsoonal tall-grass plains south of the Gulf of Carpentaria in northern Queensland. Occasionally, it also spreads and breeds in central and southern Queensland as well as the northwest plains of New South Wales. For more information and distribution records see [GBIF]

Biology

The spur-throated locust has a one-year life cycle, with populations taking several years to reach plague levels. It cannot survive prolonged drought, which limits it mainly to monsoonal regions and makes plagues less frequent than those of the Australian plague locust (Chortoicetes terminifera). Females lay eggs in cracked clay soils from October to February, which hatch in 18 to 30 days. Nymphs develop over 47 to 90 days, emerging mainly between November and February. Unlike other locusts, females scatter eggs across the landscape rather than in egg beds, and the resulting nymphs do not form bands, making control of dispersed populations difficult. Nymphs can however, occur at high densities near preferred grasses, with young nymphs feeding on short grasses and older nymphs on taller vegetation. Nymphs are vulnerable to dry conditions, making regular rainfall essential for survival, and are typically present from December to March, though they may persist into autumn if hatching is delayed. Adults usually fledge between March and April, entering an overwintering diapause where they roost in trees, often forming dense swarms that can defoliate trees and break branches under their weight. Reproductive development resumes in late spring as temperatures and day length increase. Summer rains trigger the dispersal of mature adults, which can aggregate in crops and cause significant damage, particularly to young sorghum. Under typical summer temperatures (28–33 °C), the minimum life cycle is about 220 days, from eggs through hoppers to reproductive adults.

Spur-throated locusts also undertake nocturnal, wind-assisted migrations from the onset of the wet season, sometimes traveling 700–1000 km. These movements redistribute populations across the tropics and can raise locust densities in southern Queensland, northern New South Wales, and northern South Australia, with young adults of the next generation also capable of migrating after fledging in autumn.

Habitat and ecology

The spur-throated locust primarily breeds in northern Australia’s monsoonal grasslands, especially around the Gulf region and Queensland’s Central Highlands, with additional breeding in southern Queensland, northern Western Australia, and northwest New South Wales. Swarms commonly form in the Central Highlands, northwest Queensland, and the Northern Territory. In early summer, locusts disperse to dense, tall grasses that support nymphs and fledglings, while migrations redistribute populations across the range. Young adults may also move in autumn, occasionally reaching southern New South Wales, northern South Australia, and occasionally as far south as Victoria. Young nymphs primarily feed on short grasses, while older nymphs and adults shift to taller vegetation, including pastures, trees, and a wide range of cultivated crops. These include sorghum, sunflowers, soybeans, millet, wheat, cotton, banana, and citrus. They also consume native vegetation such as eucalyptus, acacia, shrubs (Dodonaea), and various grasses, which supports their persistence in marginal environments.

Land-use change

Human-disturbed sites, such as roadsides, are commonly used for oviposition. In an irrigated region of Western Australia, females laid most of their eggs along canal banks and cleared ground nearby. in In 1973–74, swarms of this species appeared in New South Wales far south of their usual range, devastating trees and pasture after moving from sorghum fields. A major cause was the shift from grazing land to crop production, which created ideal conditions in medium forage grasses for nymphs and adults. and sources therein

Management

In Australia, swarms of spur-throated locusts typically form within their main northern breeding areas, which are often more than 1,000 km from major cropping regions. When locusts migrate south from the tropics, the Queensland government treats adult swarms in inland areas, as was done during the 2010 outbreak to prevent swarms from reaching crops. In Queensland and New South Wales, the Australian Plague Locust Commission (APLC) manages outbreaks that may spread across state borders, while landholders are responsible for treating locusts on crops as late-instar nymphs and adults using approved chemical pesticides. In Queensland, only insecticides registered by the Australian Pesticides and Veterinary Medicines Authority may be used in cropping and livestock areas, with Biosecurity Queensland providing guidance and coordinating regional efforts. Nymphs of the spur-throated locust do not form bands, which makes managing their widely dispersed adult populations during summer challenging. However, swarms can be more effectively controlled with insecticides in winter if they are detected early. Different insecticides are used for various locust species, but some can leave residues that negatively affect agricultural trade. Their effectiveness also depends on applying them correctly for the locust’s life stage and behavior.

Biopesticide trials with the fungus Metarhizium acridum have been carried out, but applications against the spur-throated locust remain limited. Chemical control—particularly with fenitrothion—remains the main management approach.

Early warning and monitoring are key components of locust management. The APLC produces monthly regional forecasts and risk statements for current and upcoming generations, using satellite imagery of vegetation greenness to identify areas where rainfall has created favorable conditions for locust survival and breeding. Field monitoring is conducted alongside surveys for the Australian plague locust, with regular stops every 10 km to carry out 250 m foot transects, recording locust numbers at different life stages and assessing vegetation type and condition. These data are transferred to a Geographic Information System (GIS) at APLC Canberra and integrated into the Decision Support System to guide locust management in eastern Australia. Effective control requires treating nearby rangeland and pastures to prevent pests from moving into cultivated crops.

Pest status

The spur-throated locust completes its life cycle within a year and cannot survive prolonged dry conditions, which generally limits populations to monsoonal regions and makes plagues less frequent than those of the migratory locust (Locusta migratoria) or Australian plague locust. Nonetheless, migrations into cropping areas can occur, particularly in the Central Highlands, where summer rainfall may trigger outbreaks. Locust swarms are capable of consuming crops, pastures, and even trees. The most significant recent outbreak occurred in central western Queensland in 2010, when Biosecurity Queensland successfully prevented the swarms from spreading eastward into the Central Highlands and Maranoa cropping districts.

Outbreaks

Five of the seven outbreaks recorded between 1935 and 1968 occurred in years with average or above-average rainfall that followed periods of drought. Significant control measures were required during the mid-1970s, mid-1990s, and the 2010 outbreak, when swarms moved southward. During the 1970s and 1990s, the spur-throated locust experienced two periods of population buildup lasting 3–5 years each, resulting in the formation of numerous swarms. Some migrated into cropping regions of central and southern Queensland and northern New South Wales, where they bred and the next generation inflicted significant crop damage.

In 1995, favorable rains led to rapid increases in both the spur-throated locust and the migratory locust, prompting large-scale preventative control. During 1996, landholders—supported by government subsidies—landholders sprayed more than 270,000 ha for crop protection. In addition, about 23,000 ha of dense spur-throated locust swarms were sprayed in inland areas by the Queensland Department of Natural Resources and the APLC to limit further spread into cropping regions. As a result, few swarms survived, and despite favorable rains in 1996–97, invasions into cropping areas were minimal, with only 3,000 ha of crops requiring treatment by landholders. With the migratory locusts, there were seven generations between 1995 and 1997, but consistent control of more than half the population each generation kept numbers well below plague levels.

During 2010–2011, coastal cropping areas in subtropical Western Australia were treated by the Queensland government to prevent swarms from reaching crops and by local landholders following invasions.

Outbreak media coverage

Title	Author(s)	Year	Geographic purview	URL
Queensland farmers hit by locust plague – but spiders may be their unexpected salvation		2025

Organizations associated with the spur-throated locust

Organization name	Acronym	Website	Type	Focus	Focus keywords	Geographic purview
Australian Plague Locust Commission	APLC	View	Government	Management, Research, Governance	Agricultural development, Control, Coordination, Education, Emergency assistance, Forecasting, Funding, Governance, Information hub, International development, Media, Monitoring, Policy, Regional cooperation, Research, Sustainable development, Technology, Training, Natural sciences	Australia
Department of Primary Industries and Regional Development	DPI WA	View	Government	Management	Monitoring, Control, Forecasting, Training	Australia
Department of Primary Industries and Regions	PIRSA	View	Government	Management, Development, Information Hub	Control, Sustainable development	Australia
New South Wales Department of Primary Industries	NSW DPI	View	Government	Education, Management	Monitoring, Control, Forecasting, Training, Natural sciences	Australia
New South Wales Local Land Services	NSW LLS	View	Government	Management	Monitoring, Control, Natural sciences	Australia
Queensland Department of Agriculture and Fisheries	QLD DPI	View	Government	Management	Monitoring, Control, Forecasting, Natural sciences	Australia
Queensland Department of Natural Resources	DNR	View	Government	Governance, Management, Monitoring, Education	Management, Control	Australia

Resources

Title	Author(s)	Year	Geographic purview	URL
Queensland locust sightings form	Queensland Department of Agriculture and Fisheries	2025
How to identify locusts		2021		View URL
Managing locusts in Queensland		2022		View URL
Locusts in Queensland		2003		View URL
Australian plague locust online learning module		2022		View URL
Agriculture Victoria Australian plague locust identification, biology and behaviour		2022		View URL
Agriculture Victoria locust and grasshopper online reporting form
CABI Green Muscle education videos	Centre for Agriculture and Bioscience International	2021
Australian Plague Locust Commission current locust situation	Australian Plague Locust Commission
Australian Plague Locust Commission locust bulletin	Australian Plague Locust Commission
APLC locust and grasshopper identification guide	Australian Plague Locust Commission
Locusts of Australia	Queensland Department of Agriculture and Fisheries	2020		View URL

Specimen contributors for this species

Bionomia links specimen records in GBIF to the people who collected and identified them. Each list shows the top 20 for this species. Read more…

Collected by

People who collected specimens of this species in the field.

• Stephen Fricker — 9 specimens collected
• Matthew Connors — 8 specimens collected
• Thomas Mesaglio — 7 specimens collected

• Ethan Beaver — 3 specimens collected
• Richard Fuller — 2 specimens collected
• Michael Kearney (Bionomia) — 2 specimens collected
• Andrew Gordon Parker — 1 specimen collected
• Jakob Fahr — 1 specimen collected
• Valentin Moser — 1 specimen collected
• Matthew Blissett — 1 specimen collected
• Mark Rosenstein — 1 specimen collected

Identified by

People who determined the taxonomic identity of specimens of this species.

• Matthew Connors — 97 specimens identified
• 태우 김 — 6 specimens identified
• Thomas Mesaglio — 3 specimens identified

• Michael Kearney (Bionomia) — 3 specimens identified
• Stephen Fricker — 2 specimens identified
• Ethan Beaver — 2 specimens identified
• Andrew Gordon Parker — 1 specimen identified
• Richard Fuller — 1 specimen identified
• Jakob Fahr — 1 specimen identified