CASE STUDY: YELLOW CRAZY

UPDATED: NOVEMBER 2017

A case study of multiple incursions of a highly threatening invader and failures to eradicate.

Species ( gracilipes)

Origin Unknown, but probably South-East Asia.

Australian occurrence Established on , in the

Northern Territory and . David Wilson Photo: Eradicated from NSW.

Potential ecological impacts Potential social and the Pacific, most often Singapore, New Yellow crazy (YCA) can form large- economic impacts Guinea and Fiji.5 There is no publicly available up-to-date data on pathways scale super-colonies, extending over YCA are likely to harm eco-tourism in 1 for YCAs. more than 100 hectares . On Christmas infested areas, including in the Wet Island, they have killed tens of millions Tropics. They are likely to reduce yields of of ecologically important red crabs and sugarcane, coffee and coconut crops by BIOSECURITY ISSUES robber crabs. Prior to a multi-million nesting at the base of these plants and dollar baiting program, they had invaded exposing the roots to disease. By farming Summary more than a quarter of the island’s sap-sucking bugs, they promote sooty has failed both to prevent new rainforest, reaching densities of more mould disease in fruit trees. They also incursions and to eradicate existing than 2000 foraging ants per square metre kill young , including chickens incursions. Since 2000, an average of and transforming the ecosystem. and pigs. According to a newspaper over 2 new outbreaks per year have been In many places where YCA flourish, report about impacts on a farm in the detected (over 30 in Queensland). There not much else does. They can remove Wet Tropics, yellow crazy ants ‘have may be many more outbreaks due to a nearly all life, leaving none for destroyed Frank Teodo’s crops, his home lack of surveillance. YCA were intercepted other insect-eating animals, and kill appliances, and they’ve scorched his eyes in Australian ports at least 161 times small animals such as lizards, crabs and attacked his dogs’.3 The economic from 1988-2011 (on average 7 times/ and bird chicks. They are on the World impacts also include the costs of control year) and at least 40 times from 2008- 6 Conservation Union’s list of ‘100 of the programs, which exceed $10 million in 2013 (on average 8 times/year). YCA World’s Worst Invasive Alien Species’. the past 5 years, including:4 (a) Arnhem represent a failure over many years to fix Queensland’s Wet Tropics World Heritage Land, $250,000 (2008/09) to the Dhimurru quarantine holes that have led to multiple Area is at grave risk, for the ants’ preferred Aboriginal Corporation, (b) Christmas incursions into Queensland, a failure habitat is moist lowland tropical forest. Island, Parks Australia $4 million up to to accord this very high environmental But climate matching suggests they are 2010/11 and another $4 million until threat the priority it warrants, a lacklustre capable of inhabiting most of northern 2014-15. In Queensland, there has and abandoned effort to eradicate and north-eastern Australia, from the been at least $2 million federal funding them in Queensland, and limited Kimberley through Darwin, Cape York provided for eradication in the Wet implementation of a threat abatement Peninsula, and down the eastern seaboard Tropics, and the Queensland government plan. It is important to prevent further of Queensland into coastal and inland had previously spent an unknown sum on incursions as new genetic material (as a parts of northern NSW.2 Their impacts an abandoned eradication program. general principle) can greatly exacerbate vary considerably from site to site and invasive impacts by enhancing adaptive 7 can take decades to manifest (as occurred Pathways evolution of . Given on Christmas Island). They have probably their potentially devastating impacts of YCAs generally arrive with imported been responsible in part for Australia’s YCA on , there should also timber. According to 2004 data, most two most recent vertebrate extinctions – be a thorough national assessment tramp ant incursions (not specific to YCA) the Christmas Island pipistrelle (2009) and have derived from South East Asia and Christmas Island forest skink (2014).

CASE STUDY: Yellow crazy ant | PAGE 1 OUR MISSION To protect the environment from harmful new invasive of the potential for eradication in the but predominantly from neighbouring species through various outbreak sites. This also means regions, and arrived by a diversity of prevention and early that the gaps in quarantine allowing pathways in association with a wide range new incursions must be identified and of commodities. The summary did not action. addressed. contain information specific to YCA. We methods. can find no specific mention of YCA or Pathway and risk analysis other tramp ants in the ICON database import requirements for timber imports. We are not aware of any detailed pathway analysis or risk assessment for New Zealand has developed risk YCA incursions. The 2012 review of the assessments of eight high priority tramp tramp ant threat abatement plan by the ants.10 The environment department in environment department noted there its review of the threat abatement plan had been no specific risk assessments noted that ‘A similar set of assessments for tramp ant species. This seems rather but framed for the Australian context astonishing given the clearly high risks of could benefit Australia’s preparedness.’11 YCAs (and other tramp ants) continuing to enter and establish, the risks of new Pre-border and border genotypes exacerbating threats, and biosecurity the millions of dollars spent so far on Given the high rate of ant interceptions in eradication and control. It should be Australia, improving biosecurity practices a high priority to conduct species- in countries of origin should be a high specific risk assessments and pathway priority. These interceptions probably risk analyses to determine how best to represent ‘the tip of the iceberg’ of exotic prevent new incursions. ants arriving in Australia. The 2006 threat A decade ago, there was an analysis of abatement plan for tramp ants noted a tramp ant interceptions from 1986-2002 lack of focus on pre-border prevention: Stronger biosecurity is vital to (by Market Access and Biodiversity, ‘preborder checks for invasive ants protect the highly endemic wildlife summarised in the background report for are not yet required nor are high-risk of Australia and its many special the tramp ant threat abatement plan).8 commodities treated pre-emptively at wild places. This is Lord Howe This found that the introduction pressure their origin to assure elimination of tramp Island, where invasive species have of tramp ants seemed to be accelerating ants’.12 The 2012 review of the threat already caused several extinctions. Photo: Robert Whyte – 90% of interceptions had been recorded abatement plan noted there had been in the most recent five years.9 Intercepted ‘limited off-shore work’.13 ants derived from diverse source areas

CASE STUDY: Yellow crazy ant | PAGE 2 The large number of YCA interceptions and incursions demonstrate major gaps in quarantine processes. The 2006 threat abatement plan notes that the ‘system of detecting tramp ants at the border relies on external inspection of all cargo’, which will ‘detect a proportion of ant contamination, and relies on the presence of actively foraging ants on the container exterior’.14 With a lack of dedicated surveillance programs for high risk pathways such as timber imports, there are likely to be several undetected incursions each year.

Surveillance Due to the eradication program for red imported fire ants and electric ants, we presume there is improved surveillance more generally for tramps ants, which would also improve the capacity to detect YCAs. The 2012 review of the tramp ant Small animals like this gecko face a cruel death in areas invaded by yellow crazy ants. threat abatement plan noted there had been a ‘modest improvement’ in national surveillance for tramp ants, in part due 25% of >6700 recorded ant interceptions high eradication potential of small to ‘some specific surveillance close to recorded to species level.19 There is populations.23 Much is being learned ongoing active eradication programs’.15 also no national body charged with about control of YCA due to control The 2006 threat abatement plan for responsibility for collecting and analysing efforts on Christmas Island and in the tramp ants noted that while state and surveillance data on tramp ants. The role . territory governments had conducted of the national Tramp Ant Consultative Because yellow crazy ants were already surveillance for fire ants in high risk areas Committee has been downgraded to established in the Northern Territory (eg. freight terminals and nurseries) there providing advice on the two national and on Christmas Island, eradication appeared to be ‘no routine monitoring or eradication programs. There is no focus in Queensland was not eligible for surveillance’ for tramp ants in other high- on preventing further incursions and national funding under cost-sharing risk or high-value areas.16 ‘There is no longer routine reporting of arrangements with other governments. surveillance data’.20 We have been advised there has been no This meant eradication had to be funded dedicated surveillance for YCAs, including by the state government. Because of in facilities that receive timber imports, Responses to incursions this, the Queensland government was which are high risk areas for YCAs. We Since the first detection of YCA in very slow to act, and the eradication understand a substantial proportion of Queensland in 2001, the species has been program when it was implemented, was YCA colonies have been detected in the found in over 30 sites including at Cairns, starved of funding. The government vicinity of such facilities, many (or most) Townsville, Hervey Bay, Maryborough, ended it in late 2012, saying that it was detected due to reports from the public Caboolture and Brisbane.21 In 2004 it was ‘no longer feasible’. The Queensland rather than from surveillance. The threat also detected for the first time in NSW. government website on yellow crazy abatement plan notes that ‘shortfalls This is the only incursion known in NSW ants reports that ‘known infested areas in current surveillance mechanisms for even though 40% of interceptions were have increased since 2007’ and that tramp ants are illustrated by chance occurring in NSW ports.22 several had been discovered in the discoveries of incursions, such as by previous year (2012-2013), ‘significantly In some respects, yellow crazy ants are members of the public’.17 increasing the total area of infestation’.24 ideal candidates for eradication because This is indicative either of continued One impediment noted in the review of they do not spread as easily as other breaches of biosecurity or a lack of the tramp ant threat abatement plan is ants, since the queens mostly cannot effective surveillance (or both). Since the the low and declining diagnostic capacity fly (the colonies bud to become super- Queensland government abandoned in most state and territory governments colonies). In 2004, the NSW government eradication, the federal government for invasive ants (and other invaders), due acted quickly to eradicate a population provided $2 million to the Wet Tropics to a lack of taxonomists.18 The diagnostic on Goodwood Island near Yamba. In the Management Authority to eradicate an accuracy for ants – as revealed in the Northern Territory, yellow crazy ants have Pest and Disease Information System been eradicated from at least 20 locations outbreak near Cairns. database (1986–2003) – is low, with only over 100 hectares, showing there is

CASE STUDY: Yellow crazy ant | PAGE 3 ISC questions the decision by the CHANGES NEEDED MORE ABOUT YELLOW Queensland government to abandon eradication and is concerned that it is Pathway and risk analysis CRAZY ANTS simply due to unwillingness to allocate • Detailed pathway analysis and risk Yellow crazy ants demonstrate the power resources. Most biosecurity funding in assessment for YCAs should be of numbers and the benefits of social Queensland goes to agricultural priorities conducted and made readily publicly cooperation. They are able to dominate (dingoes, wild dogs and bovine johne’s available, along with analysis of why large areas by forming super-colonies disease). Our most recent information there continues to be a high rate of YCA with multiple nests and multiple queens. was that an effective eradication interceptions and incursions. The largest have up to 300 queens and program needed about a million dollars extend over several hundred hectares. annually. We suspect the problem is Pre-border and at-border They spread mostly by budding. A mated one of priorities rather than feasibility or biosecurity queen leaves her birth nest with some unaffordability. The work in the Northern workers and sets up a new nest nearby. • There should be a concerted effort Territory shows there is high eradication The boundary of a super-colony can to reduce YCA (and other tramp ant) potential of small populations (such advance by 3 metres a day. as are in Queensland).25 There is no incursions into Australia, based on the feasibility or cost-benefit analysis publicly risk assessment and pathway analysis, The adults eat nectar and honeydew and available to justify the decision by the and targeting high risk countries and feed their brood on animals killed or Queensland government. cargo. scavenged. They don’t sting but squirt formic acid, which blinds and debilitates A serious YCA eradication attempt in Surveillance their prey. Their great numbers allow Queensland would require considerable them to overwhelm animals far exceeding • A risk-based surveillance program for improvements in quarantine to prevent them in size – crabs, lizards, bird chicks. new incursions. In December 2013, the yellow crazy ants – as part of a broader Queensland government said one reason invasive ant program - is needed. It Although their preferred habitat is for abandoning the program is the high would benefit from the inclusion of moist tropical forest they also live in the rate of incursions, which ‘threatens the a citizen science focus and requires subtropics and in harsh, dry areas such as long term success of any eradication strengthening Australia’s capacity to Arnhem Land. They invade horticultural program.’ From 2008-2013, there was an identify ant species. plantations and urban areas. average of 8 interceptions a year, 57% in Australia has seen how bad yellow crazy 26 Queensland. Incursion responses ants can get. An ‘invasional meltdown’ From 1988 to 2011, there were 161 • Greater transparency and public on Christmas Island triggered by crazy interceptions, an average of seven a accountability is needed in decision- ants has resulted in a “rapid, catastrophic year.27 We suspect that only a small making about YCA eradication. It is shift in the rain forest ecosystem”, as proportion of YCA arriving in Australia are not known whether there has been summarised by Dennis O’Dowd and co- intercepted. any analysis by the Queensland researchers: government of the cost to eradicate In invaded areas, crazy ants extirpate The lacklustre eradication program for all or some YCA populations, whether the red land crab, the dominant YCA in Queensland contrasts with those a feasibility assessment of eradication endemic consumer on the forest for the two nationally funded programs was developed, whether a cost-benefit floor. In doing so, crazy ants indirectly for red imported fire ants (RIFA) and analysis underpinned the decision to release seedling recruitment, enhance electric ants, which are economic, social abandon eradication, or how much an species richness of seedlings, and and environmental threats, and are not effective eradication program may cost. established elsewhere in Australia (albeit slow litter breakdown. In the forest the RIFA program is still far from being • There should be an assessment of all canopy, new associations between this adequately and securely resourced). YCA populations to determine the invasive ant and honeydew-secreting National funding is restricted to species feasibility for eradication, containment scale accelerate and diversify that can be totally eradicated from or control of each population. impacts. Sustained high densities of Australia. For a country of such vastness foraging ants on canopy trees result and ecosystem diversity, this is a short- Lessons learned in high population densities of host generalist scale insects and growth sighted approach that means neglect • There is a need for independent public of sooty moulds, leading to canopy for many incursions that are of national analysis of biosecurity relevant to YCA dieback and even deaths of canopy environmental significance. to determine how future incursions of trees. this and other tramp ant species can Research be prevented and the environmental Yellow crazy ant impacts have varied, There has been limited research on YCA threats they pose abated, and national depending on their density and on the and other invasive ants in Australia.29 coordination and funding for threat invaded ecosystem. The Queensland abatement improved. Government’s risk assessment says the

CASE STUDY: Yellow crazy ant | PAGE 4 impacts are hard to predict but are CONTACT US 2013. Senate Question No 2671. Question likely to result in “a general decline in upon notice 14 January 2013. • Visit invasives.org.au for more biodiversity”. They can cause damage by O’Dowd D, Green P, Lake P. 2003. Invasional killing animals, monopolising resources information about the Invasive Species “meltdown” on an oceanic island. Ecology and compromising tree health by farming Council and to get in touch. Letters 6: 812–817. sap-sucking bugs. Office of Environment & Heritage. 2005. Robber, red and blue crabs are Invasion of the Yellow Crazy Ant, Anoplolepis completely eliminated in crazy ant areas REFERENCES gracilipes (Fr. Smith) into NSW – profile. NSW Government. (http://www.environment. on Christmas Island. They kill small Abbott K. 2005. Supercolonies of the invasive nsw.gov.au/threatenedspeciesapp/profile. animals, including bird chicks, turtle yellow crazy ant, Anoplolepis gracilipes, on an aspx?id=20010) hatchlings and lizards. oceanic island: forager patterns, density and biomass. Insectes Sociaux 52: 266–273. Sakai A, Allendorf F, Holt J, et al. 2001. The Crazy ants are highly aggressive to other population biology of invasive species. Annu Bateman D. June 28, 2014. Trail of devastation ant species. Only two of 40 ants on Rev Ecol Syst 32:305–332. Christmas Island are able to coexist with as Cairns region declares war on yellow crazy yellow crazy ants. In , yellow crazy ants. Cairns Post. http://tinyurl.com/q2sox4m ants aggressively defend flowers from Biosecurity Queensland. 2013. Biosecurity ENDNOTES other nectar-eaters. Their large-scale Queensland response to Background Briefing’s 1 http://www.ccfqld.com/News-page/ removal of insects deprives other insect- questions, Yellow Crazy Ants. ABC Radio National. (www.abc.net.au%2Fradionational%2 update-from-biosecurity-qld-fire-ants-in-the- eaters, such as lizards and birds, of food. gladstone-area/ Monopolisation was noted at a site near Flinkableblob%2F5146684%2Fdata%2Fbiosec urity-queensland-response-data.pdf). Program 2 Allen et al. (2004), Department of the Cairns. aired 8 December 2013. Environment Yellow crazy ants farm sap-sucking bugs Commonwealth of Australia. 2006. Background 3 Lowe et al. (2000) for their honeydew (excreted sugary document for the threat abatement plan 4 Allen et al. (2004) liquid) and protect them from predators. to reduce the impacts of tramp ants on 5 Allen et al. (2004) The build-up in bugs and sugar biodiversity in Australia and its territories, 6 Allen et al. (2004), Vinson (2013) encourages the growth of sooty mould, Department of the Environment and Heritage, which can severely compromise tree Canberra. 7 Moloney & Vanderwoude (2002), Department of the Environment health and is sometimes fatal. CSIRO. 2014. Eradicating pest ants from the 8 Department of the Environment Yellow crazy ants also cause agricultural Top End (http://www.csiro.au/Outcomes/ 9 Department of the Environment damage. They have killed young chickens Safeguarding-Australia/TropicalPestAnts.aspx) 10 Vinson (2013) and pigs. They reduce yields of coffee, Csurhes S, Hankamer C. 2012. Pest coconut and sugarcane crops by nesting risk assessment: Yellow crazy ant Anoplolepis 11 Vinson (2013) at the base of these plants and exposing gracilipes. Biosecurity Queensland, Queensland 12 Avant (2014), Lard et al. (2006) the roots to disease, and promote sooty Government. 13 Antony et al. 2009 mould disease in fruit trees. On one of Department of Sustainability, Environment, 14 Costs to 30 June 2014, Mike Ashton, the islands, the abundance of a Water, Population and Communities. 2012. personal communication. Hafi et al. (2014) said sap-sucking insect associated with sooty Review of the Threat Abatement Plan to reduce the costs were $411 million (but they don’t mould on citrus and cinnamon increased the impacts of tramp ants on biodiversity give a source for it). up to 100-fold in the presence of yellow in Australia and its territories 2006–2011. 15 International Plant Protection Convention crazy ants, and up to 90% of leaves were Australian government. (2010). The 2001 detections were at Brisbane’s infected. Dominiak B, Gott K, McIver D, et al. 2011. main cargo port (Fisherman Islands), and in the Scenario tree risk analysis of zero detections southwestern suburbs of Wacol and Richlands. and the eradication of yellow crazy ant 16 Keith and Spring (2013) Anoplolepis gracilipes ( (Smith), in New South 17 Keith and Spring (2013) ABOUT OUR CASE Wales, Australia. Plant Protection Quarterly STUDIES 26(4): 124-30. 18 Keith and Spring (2013b) 19 Keith et al. (2013) Our case studies illustrate the need for Drescher J, Feldhaar H, Blüthgen N. 2011. 20 Keith et al. (2013) changes in how Australia prevents the Interspecific aggression and resource establishment of new invasive species. monopolization of the invasive ant Anoplolepis 21 SCoPI (2013) gracilipes They were compiled using publicly in Malaysian Borneo. Biotropica 43(1): 93-99. available information at the time of the last update. We would welcome new Hoffman B. 2014. Quantification of information or updates to biosecurity supercolonial traits in the yellow crazy ant, response for inclusion in future updates. Anoplolepis gracilipes. Journal of Insect Science 14: Article 25 Minister for Agriculture, Fisheries and Forestry.

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