StowawaysStowaways

Number 2 October 2002

ISSN 1175-6233 Contents Is that a scorpion in your weapon?

Is that a scorpion... 1 Cattle ticks were introduced to and fruit fly to name a few”. The Victoria, Australia, via horses en risk of invasive weeds is also high. Spiders in grapes 2 route to Egypt in WWI. German Siam weed is a risk because it has Freshwater invertebrates 4 wasps arrived in New Zealand in hooked seeds that adhere easily to Sleeping dragons 5 aircraft parts at the end of WWII. goods. It is likely to be invasive in As armies have moved around the New Zealand and the weed is toxic Mosquitoes of New Zealand 6 world, they have tended to take enough to kill young cattle. weeds and pests with them, Mosquito interceptions 7 All equipment will be visually accidentally stowed away in their Saltmarsh mosquito update 7 inspected before it is shipped out equipment. The New Zealand from East Timor. This will include BIOSECURE 8 Defence Force returning from East everything from boxes of plastic Timor is part of the biggest Argentine ants spread 10 spoons to armoured personnel biosecurity programme ever carriers, and the 47 television sets Dead ants 11 undertaken for repatriating New that will need the backs removed Zealand troops. Key to New Zealand ants 11 for careful inspection of the insides. Crazy ant species found 12 This operation is particularly As an example of how thorough important because of the vast inspections need to be, consider a Scorpion update 12 range of biosecurity hazards for box of immaculately clean kitchen New developments in wasp... 13 New Zealand in East Timor. MAF knives, carefully packaged with Quarantine Service programme polystyrene. But lurking Stowaway hit list 13 coordinator, Brian Whimp, underneath the polystyrene insert Illegal immigrant arrives ... 14 explained, “There is a huge variety MAF inspectors found Invasion improves lakes 14 of potential stowaways in East Trogoderma beetles known as a Timor – snakes, spiders, scorpions pest of stored products. Paper wasp heads south 15

Argentine ants kill wasps 15

Recent Publications 16

1 Stowaways No. 2 October 2002

Spiders in grapes

It may also be necessary to The New Zealand Defence Force Fresh, juicy grapes – it’s mid-winter fumigate some items. “Things like is working closely with MAF’s and you look forward to the burst of trucks can be washed down and quarantine service to complete the summer flavours, courtesy of steam cleaned, but other items will operation. The withdrawal started international trade. As you carefully be more difficult to deal with. A in mid-September in preparation for select your treat from the large number of camouflage nets handing over to the Thai defence supermarket, you are horrified to have been in storage and are force in mid-November. The see a black spider scuttle from the covered in spiders and seeds and biosecurity operation aims to be bunch and seek sanctuary in an who knows what else. It is not completed so everyone is home in adjacent cluster. You may not physically possible to remove time for Christmas. suffer from arachnophobia, but everything from these nets, so Contact: Brian Whimp, MAF where did that spider come from? fumigation is the way to go”, says Quarantine Service, Whangarei In September 2002, New Zealand Mr Whimp. [email protected] approved the resumption of trade in table grapes from California. The trade was suspended in November 2001 after four live black widow spiders and a number of other exotic spiders were found at the

New Zealand Defence Force border over a 3-month period. Ministry of Health Chief Technical Officer Sally Gilbert said that apart from permanently suspending trade, there was no way to guarantee spiders would not enter New Zealand via table grapes.

In 2000 and 2001, New Zealand imported more than 5700 tonnes of table grapes from California, and New Zealand Army Mogs are being shipped home from East Timor, but first they will more than 4800 tonnes from be cleaned and inspected to prevent plant and animal pests stowing away. Australia. Smaller volumes were imported from Mexico and Chile. Over this same 2-year period, there were 58 detections of exotic spiders Spider bites in grapes, with most (86%) of these originating from California. More Most spiders have venom. neurotoxic; that is, it affects the than 80% of the exotic spiders However, few spiders are human nervous system beyond found made it past our border capable of biting people the site of the bite. Other spider security and were discovered once venom is necrotic (e.g. the white- because they are not able to they had been transported within tailed spider Lampona pierce human skin with their New Zealand (see map). This fangs. Spider venom is produced cylindrata) and causes damage highlights the difference in in glands behind the jaws and such as ulcers and blackening of perception associated with different empties along ducts in the fangs the tissues surrounding the site of taxonomic groups. Imagine the and is used to paralyse or kill the bite. The toxicity of spider outcry if 58 snakes were detected in their prey. Some spider venom is venom varies with the species. New Zealand over the same period. 2 Stowaways No. 2 October 2002

The Ministry of Agriculture and web. For example, many of our Jacqueline Beggs Forestry (MAF) visually inspect native birds feed on spiders and Landcare Research between 600 and 920 bunches of other invertebrates. [email protected] grapes per consignment, giving Spiders have proved tough to kill – MAF a statistical confidence level some can survive fumigation and of 99% that the actual rate of cold temperatures. The existing infestation is no more than one import health standards require detection per 200 bunches of table grapes from Australia and grapes. The 5700 tonnes of grapes California be fumigated. Trials from California equates to about 14 show this can achieve a 92% million bunches of grapes. It is not reduction in the number of live surprising then that border spiders found in grapes. Many inspection did not detect all 50 spiders can also survive the spiders originating from California refrigeration associated with because that is a rate of only 1 per storage and shipping; Californian 280 000 bunches of grapes. grapes are stored at about 1°C for Some spiders may well have between 23 and 111 days. Even escaped detection. There is some with fumigation and cold storage, evidence for this – more large almost all (c. 90%) of the detections spiders are found than would be in New Zealand, when the status of expected, perhaps because the spiders was known, involved people are more likely to report live spiders. In most cases it was finding a large spider than finding unknown whether spider eggs were a small spider. So where did all dead or alive. the small spiders go? Or perhaps MAF has revised the import smaller spiders are more health standards for imported vulnerable to fumigation and table grapes (see: cooling, so more large spiders www.maf.govt.nz) and will survive and are reported. review the standard at New Zealand has already been the completion of the invaded by a number of exotic first export season. spider species, predominantly from Australia. Like many invasive invertebrates, they have mostly colonised human environments and modified landscapes. Nevertheless, some are found in natural ecosystems. There is good evidence that native katipo populations have been displaced by the arrival of exotic spiders. Spiders can be predators and competitors of native invertebrates, and potentially have flow-on effects throughout the food Location of alien spiders found in imported grapes since 1998 3 Stowaways No. 2 October 2002

Freshwater invertebrates

How vulnerable are New Zealand’s

freshwater ecosystems to invasion Richard Toft by new organisms and what are the consequences of such an invasion? How do invasive species arrive? Do interactions between freshwater, estuarine, and marine ecosystems affect invasions? We need to understand our freshwater ecosystems, and how they compare to similar ecosystems in other parts of the world to answer these questions.

New Zealand lakes and streams have their own special fauna. In contrast to most freshwater systems elsewhere, New Zealand has a high proportion of endemic species, a A native stonefly (Order: Plecoptera) few endemic genera, and numerous invader. We just don’t know! genera and families that are shared resources in streams. A low supply Similarly, species with (geologically) with Australia and/or South America. of particulate organic matter is For example, all New Zealand thought to account for the low recent relatives in Australia may be displaced by a more aggressive, genera of stoneflies are endemic. numbers of shredders. These special features of New Zealand related species from across the New Zealand’s small size, isolation streams may have led to the Tasman. and geological history in the 80 evolution of a resilient fauna. million years since it was part of Impacts on native species New Zealand’s lakes and river Gondwana have contributed to this. Rainbow trout are known to have ecosystems have already had Short, shallow, swift and stony- reduced the populations of koura ecological impacts from the bottomed streams provide the (Paranephrops planifrons) and introduction of plants, fish, and environment for much of New crab (Halicarcinus lacustris) in invertebrates. There are about 26 Zealand’s running water Lake Waingata. invertebrate fauna. Larger rivers species of introduced freshwater The endemic mollusc and streams on gentler terrain invertebrates established in New Glyptophysa variabilis has been provide a further range of habitats Zealand. Most of these are replaced to some degree by the including silt-bottomed, lowland cosmopolitan, or nearly so, but a introduced mollusc Physa acuta. channels and gravel-bedded few species (four molluscs, one braided rivers. There are also a beetle, and four mosquitoes) have The endemic mosquito Opifex variety of lake types. spread from a limited native range to fuscus appears to have been a limited or unknown range within displaced by the introduced Stream communities in New New Zealand. Ochlerotatus australis on the Zealand have a high species Otago coast. richness of browsers and a low Endemic groups are vulnerable to species richness of shredders extinction should they be displaced Graham Sandlant compared with those in six other by an invading species, because [email protected] regions of the world. It may be that a they are found nowhere else in the generalist feeder lifestyle is favoured world. However, they are adapted This research was funded by the in New Zealand streams because of to their habitat in New Zealand and Foundation for Research, Science the unpredictable nature of may be quite robust in the face of an and Technology 4 Stowaways No. 2 October 2002

Sleeping dragons

There are sleeping dragons in your invertebrates in New Zealand. If we (subsequently eradicated), and neighbourhood. There may even are serious about stemming the tide another new to the South Island. In be some in your backyard! of invertebrate invasions, it is the case of fungus gnats, the critical that we are able to detect Malaise trap samples contained at The sleeping dragons are invasive founding populations of newly least two (and possibly six) invertebrates in the early stage of naturalising species so risk adventive species that have not naturalisation. When a new species assessments can be carried out previously been arrives, there is often a lag period while eradication is still a practical recorded in between initial establishment and and affordable option. New Zealand. subsequent spread. In the case of invertebrates, the initial “sleeping” Some preliminary investigations populations can go unnoticed, and were started last summer. Tent-like the invaders can become Malaise traps were set up to collect widespread before we are aware of flying insects at 16 residential their arrival. A new Landcare properties in Nelson and Research project will investigate Wellington. Other varieties of traps the prevalence of invertebrate were trialled around Port Nelson. sleepers and identify the best ways Although sample identifications are to sample for them. far from complete, and many insect One of them, a South African groups have yet to be looked at, The main pathway for invertebrate species called Leia arsona, is the there are already a number of incursions is trade and most common fungus gnat in urban interesting results and some transportation between cities, so it Nelson. Results for moths include causes for alarm. is likely that the centres of significant range extensions for two colonising populations will be in Traps around Port Nelson collected introduced species. One of these, urban areas. It is concerning, five species of ants, including one previously known from Auckland therefore, that there is very little Australian species not previously and Northland, is an Australian general surveying of urban recorded in New Zealand species that mines the leaves of kanuka. The other, a citrus flower moth, was previously known from Northland and the Bay of Plenty. Richard Toft Next summer we will expand the project by trapping in some new urban areas, such as Auckland, and continue to trial various sampling methods. Traditional advice is to let sleeping dragons lie, but we suggest that finding the lair gives us the option of slaying the dragon before it awakens.

Richard Toft Landcare Research [email protected]

This research was funded by the Foundation for Research, Science Leia arsona is a South African fungus gnat making its home in New Zealand. and Technology 5 Stowaways No. 2 October 2002

Mosquitoes of New Zealand

New Zealand has 12 endemic and 4 introduced mosquito species.

Ochlerotatus notoscriptus Introduced pre-1918; also in Micheal Womack striped mosquito Australia, New Caledonia, Papua New Guinea, and Indonesia

Ochlerotatus australis Probably introduced; also in saltwater mosquito Australia

Ochlerotatus chathamicus Endemic, Chatham Islands only Chatham Island mosquito An Asian tiger mosquito feeds on a human. At Port of Auckland in Ochlerotatus antipodeus Endemic, Northland to Stewart Is September 2001, 30 of these mosquitoes were found inside a ship Ochlerotatus camptorhynchus Introduced 1998; also in Australia from Japan. southern saltmarsh mosquito

Ochlerotatus subalbirostris Endemic, east coast Otago, Fact File Southland & Stewart Is. Mosquito-borne diseases

Opifex fuscus Endemic, widely distributed around New Zealand is one of a few saltpool mosquito NZ coast countries in the world with no Culex asteliae Endemic, Northland, Auckland & known transmission of human Coromandel arboviral disease such as dengue fever and Ross River fever. Culex pervigilans Endemic, Kermadec Is., all NZ, to vigilant mosquito Auckland Is. A mystery case of malaria near Culex quinquefasciatus Introduced in the 1830s; virtually London's Heathrow Airport has brown house mosquito cosmopolitan with man been blamed on a stowaway mosquito. The patient had not Culex rotoruae Endemic, Rotorua recently been to any country with Rotorua mosquito malaria, but works near Heathrow. Culiseta novaezealandiae Endemic, SE Otago An outbreak of West Nile Culiseta tonnoiri Endemic, northern North Is. & encephalitis, a mosquito- western South Is. transmitted viral disease from Africa, was first recorded in the US Cocquillettidia tenuipalpis Endemic, Auckland, Rangitikei, Westland, and Southland in 1999. Since then it has spread rapidly, and 47 people have died Cocquillettidia iracunda Endemic, Northland to from the disease. The virus is also Coromandel, Buller and Westland known to infect 110 species of bird.

Maorigoeldia argyropus Endemic, throughout New Zealand Risk goods

Stowaway mosquitoes have been Name changes found at New Zealand's border in: The world wide genus of Aedes Zealand Aedes are now in the used machinery mosquitoes (900 species in 44 genus Ochlerotatus. subgenera) has been split. Aedes used vehicles Graham Sandlant now contains over 370 species, [email protected] used tyres and 3 subgenera of Aedes have been elevated to generic rank: dirty containers This research was funded by the Ochlerotatus (560 species), refuse drums Foundation for Research, Science Verrallina (90 species), and and Technology aircraft 6 Ayurakitia (2 species). All New Stowaways No. 2 October 2002

Mosquito interceptions

Eight species of mosquito have been intercepted at New Zealand's border. Since 1 January 1998, there have been 14 interceptions of exotic mosquitoes of public health significance.

Name Interception Details Diease Transmission

Aedes aegypti Intercepted 1950; 1999, 2001; Dengue fever, yellow fever, Ross yellow fever mosquito cosmotropical within 20°C isotherms River fever

Aedes albopictus Intercepted 1993,1998, 1999, 2001; 22 viruses including dengue fever Asian tiger mosquito potential to survive in NZ; widespread and yellow fever

Aedes vigilax Intercepted in 2002; the major coastal Ross River fever, Barmah Forest pest species for NSW, Australia disease, and dog heartworm

Ochlerotatus japonicus Intercepted 1993, 2001, 2002; potential Japanese B encephalitis, West Nile to survive in NZ; originally from Asia encephalitis

Culex annulirostris Intercepted in 1929, 1999; present in Murray Valley encephalitis, Ross Australia, SE Asia, and the South Pacific River fever

Culex australicus Unconfirmed interception in 1998; Does not feed on humans present in Australia, New Caledonia, and Vanuatu

Culex pipiens pallens Intercepted 2001; most common Several encephalitids, including common house mosquito mosquito in the world West Nile encephalitis and Japanese B encephalitis

Tripteroides tasmaniensis Intercepted 1993; present in Australia Not known to carry diseases

Southern saltmarsh mosquito update

Locations of known incursions The southern saltmarsh mosquito potential habitat of almost is known to transmit Ross River 3000 hectares. Initially, the virus. The mosquito was first plan was to eradicate the discovered in Napier in mosquito in Napier, Gisborne, December 1998, when residents Mahia and Porangahau and to complained of being fiercely contain and control the spread bitten during the day by large of the mosquito in the Kaipara numbers of mosquitoes. and Mangawhai areas. The Eradication operations appear to Government has now decided to have been successful in the move to full eradication at all Napier area, but attempts to sites. The programme will involve eradicate the more recently aerial and ground spraying, using discovered incursions of southern S-methoprene, an insect growth saltmarsh mosquitoes from six regulator that stops the mosquito other sites are continuing. pupae hatching into adults, and the biological spray Bti. Around $30 million will be spent in the next 4 years to eradicate Sally Gilbert the exotic mosquito from the Ministry of Health Kaipara area, which covers a [email protected] 7 Stowaways No. 2 October 2002

BIOSECURE – prototype ready for trial

New Zealand as an island nation resources to stop pests arriving, usual enemies and competitors to constantly battles the threat of establishing, and spreading. A keep their numbers down. introduced weeds and pests. With prototype is now ready to be trialled BIOSECURE also factors in the ever-increasing trade volumes and by staff from the Department of degree of human disturbance in tourism, we must always be on Conservation and Ministry of New Zealand ecosystem such as guard against invaders. But with Agriculture and Forestry. Users log deforestation and introduction of our limited resources, what should on, fill out fields specific to their real exotic plants. These disturbances we be most viligent against? Which or hypothetical invasive species make an ecosystem more invaders have the greatest potential problem, and BIOSECURE posts a vulnerable to invasion. As well to run rampant here, to the result report. BIOSECURE looks at an detriment of native ecosystems? Biosecurtiy agencies can run risk ecosystem’s proximity to ports of Landcare Research is leading a analyses with a wide range of entry, which countries these ports project to develop the most environmental indicators, including receive goods form, and how comprehensive, computerised, risk climate, host plant distribution, soil these goods spread out within profile system in the world. fertility, and whether enemies and New Zealand. BIOSECURE is a web-based system competitors are present. Invaders Diana Leufkens to help biosecurity managers often thrive in new climatic Landcare Research decide where best to focus their conditions if they do not have their [email protected]

Red imported fire ants In early March 2001, a nest of red imported fire ants Richard Toft (Solenopsis invicta) was found at the Auckland International Airport. The nest was treated and all the ants killed. Surveys have not located any more of these ants in New Zealand. As well as a painful sting (hence their name), fire ants can alter the ecological balance by damaging plants and reducing food sources for native ant species and other insects. So, if we do not want this species established in New Zealand, how do we keep them out?

BIOSECURE – assessing fire ants

BIOSECURE can be used to assess the risk of red imported fire ant invading New Zealand; to predict where they are most likely to come from; how they will arrive; and where they will establish.

Firstly, BIOSECURE produces a world-map showing the native distribution of the fire ant and the location of introduced populations (Fig. 1). Fig ure 1. Yellow dots are the native range of the ant, and bright green area represent locations where the fire ant 8 has been found outside its native range. Stowaways No. 2 October 2002

Then, by overlaying location data on digital maps, BIOSECURE estimates biological and environmental parameters (such as temperature, rainfall, soil nutrients, invertebrate assemblage) for each location. These parameters are used to define the niche of a species or taxonomic grouping. For example, a digital map of global rainfall (Fig. 2) is used to estimate the range of Figure 2. Rainfall rainfall in which the fire ant can survive. In this case, the darker the colour, the higher the rainfall.

Similarly, BIOSECURE compares the composition of ant communities found in different parts of the world (Fig.3) with what is found in New Zealand. In this case, we are still collecting data on ants in those areas of the world coloured grey. Figure 3. Compositiion of ant communities

Finally, BIOSECURE uses the information on niche to produce a likelihood score for a species surviving in a location. The scores are produced as maps and tables at a range of scales (from global to within-New Zealand). Figure 4 shows the likelihood of red imported fire ant surviving, based World on minimum temperature. The darker the colour, the greater the likelihood of establishment.

Gary Barker Landcare Research New Zealand [email protected]

This research was funded by the Nelson Region Foundation for Research, Science and Technology FIgure 4. Liklihood scores for a species surviving in a location 9 Stowaways No. 2 October 2002

Argentine ants spread

Where they are now? the ants have Argentine ants continue to spread been found in, around New Zealand; new and their ability to

locations include infestations in survive in urban Anne Sutherland Nelson and Christchurch. areas even if the Argentine ants are slow to disperse surrounding habitat naturally because they do not have is too cold. We used a winged form. They are good GIS to map the stowaways, though, and are predicted distribution transported around New Zealand (see map). with human goods. Even so, it will So far, Argentine ants have take many years for them to spread not spread widely into native to all favourable areas, especially habitat. We predict native forest isolated ones. is unlikely to be invaded, but Where to next? over 35 000 ha of native habitat is likely to be highly Expect to be invaded by Argentine suitable for invasion (e.g. ants if you live in northern New costal dunes, open Zealand, particularly coastal areas. scrubland). This high-risk Most urban areas in New Zealand habitat is mostly in are also likely to be invaded. Northland, Auckland Urban Auckland is highly suitable and northern for Argentine ants, and even lower offshore islands. North Island towns and cities are vulnerable. Christchurch and coastal towns in Nelson and Marlborough will probably support Argentine ants. You can be thankful for a cold climate if you live south of Christchurch, as the cold is likely to protect you from this invasion.

We predicted the likely final extent of Argentine ants in New Zealand using temperature data from sites with Argentine ants, considering the habitats

Predicted distribution of Argentine ants in New Zealand

10 Stowaways No. 2 October 2002

Dead ants

“One ant, two ants … 12 ants," mutters Jo as she scours the Port Nelson site that was treated with Richard Harris poison bait to kill Argentine ants just over a year ago. Only one small colony is found. To have such a low tally after hours of searching is great news, and it is even better at one of the two sites treated on Tiritiri Matangi Island – no ants were found. Before treatment, the ants numbered in the tens of thousands. Next summer we will develop more- sensitive monitoring methods to detect low densities of Argentine ants, and then resurvey in detail the treated sites. And the final step to achieve eradication at these sites? Develop a method for eliminating Putting out ant bait at Port Nelson any survivors before they have a chance to build up in numbers. Key to New Zealand ants

It’s black, has six legs, and dozens three species that are not Richard Harris of them are swarming all over your established here but have made Landcare Research driveway. You know it’s an ant, but recent incursions and are highly [email protected] is it a native or an introduced invasive species we do not want species? And if it is introduced, has (the red imported fire ant and two The Argentine ant research was it been here for years, or is it species of crazy ant). funded by the Foundation for something new? Research, Science and Also, if you have an infestation of Technology, Department of Anyone who has access to a ants it is important to know which Conservation, MAF Biosecurity, binocular microscope can use a species they are to decide what Environment Bay of Plenty and Port new key on our website (http:// treatment is appropriate. Nelson stowaways.landcareresearch.co.nz) to identify worker ants.

Why is the identity of an ant important? To keep out new invaders. Only by picking up newly arrived species early is there a chance of eradicating them. For example, detecting Argentine ants arriving on an offshore island, or a newly established colony of fire ants gives an opportunity for eradicating these pests before they establish and spread. Included in the key are 11 Stowaways No. 2 October 2002

Crazy ant species found

The red imported fire ant surveillance programme has

snared two more exotic ant Richard Toft species. Two species of crazy ants, Paratrechina longicornis, and the yellow crazy ant (Anoplolepis gracilipes), were detected at the Port of Auckland in April.

Only one nest of the yellow crazy ant was found, and this was destroyed. No further specimens Anoplolepis gracilipes (yellow crazy ant) have been found. This species is well known for the devastating Mangere, Auckland, as a result of that are known to receive impact it has had on the Christmas fire ant surveillance activity. containers from the port. People Island (Australian territory) land Eradication results so far are working in these areas have been crab population. encouraging. The P. longicornis asked to report any unusual ant The other species of crazy ant (P. infestations have been treated, and activity. There will be further longicornis), found in many parts of monitoring continued over the winter surveillance for crazy ants once the world where it is known as an to ensure that treatment was temperatures rise again in the urban nuisance pest, was more successful. Information has been spring. widely spread within the port area. sent to businesses within the Amelia Pascoe Specimens were subsequently Auckland port area, and to all Animal Biosecurity, MAF found at a transitional facility in transitional facilities in Auckland [email protected]

Weed newsletters Scorpion Update "What’s New in Biological Control of Weeds?” is produced An unconfirmed sighting of quarterly to inform people about scorpions in the Hawkes Bay was sustainable biological control reported to MAF in 2000 solutions for weeds. “Wise up to (Stowaways No.1). Staff from MAF Weeds!” is produced twice a searched the Hawke’s Bay site, as year and features stories about well as four other sites that how to identify weeds, new received goods from the same weeds to watch out for, and source. No scorpions were found. weed ecology. Both newsletters are available from MAF continued surveillance www.landcareresearch.co.nz. around the sighting area for two months and no Contact Lynley Hayes to be scorpions were found. added to the mailing list. The area was treated with Lynley Hayes a residual insecticide. Landcare Research PO Box 69, Lincoln. Amelia Pascoe [email protected] Animal Biosecurity, MAF 12 [email protected] Stowaways No. 2 October 2002

New developments in wasp control

This research was funded by the Foundation for Research, Science and Technology

Stowaway hit list

Currently the Invasive Species Landcare Research is developing that we are able to culture has been Specialist Group is developing a a range of tools for controlling found in all wasps, and there are no database on invasive species wasps. Some are for widespread obvious candidates for bacteria worldwide. Included in the long-term control, and others for associated only with wasps. database is a list of the “100 of the localised short-term control. It is worst invasive species in the likely that several control tools will world”. be needed to solve the wasp Species were selected for the list problem. according to two criteria: their One approach to developing novel serious impact on biological wasp control options is via a Trojan diversity and/or human activities horse – using organisms that wasps and their illustration of important don’t recognise as a threat to issues surrounding biological defeat these persistent invaders. Rickettsia in the fat body of an invasions. The list illustrates the We are working on the idea that insect. The small particles are around 0.6 mm long incredible variety of species (plant through genetic modification we and animal) that have the ability, can alter organisms that would All is not lost, however, as not just to travel in ingenious ways otherwise be harmless associates Australian researchers have found but also to thrive and dominate in of wasps to kill them. an organism smaller than a new places. Working out which bacterium which is present in their What we need to make this process species to include in the list was wasps. work is a microbe exclusively no easy task — there are so many contenders. associated with wasps, so that no This organism is not able to be other insects would be affected. grown outside a wasp body and is How many species on the list have We are collaborating with very likely to be specific to wasps. already invaded New Zealand? researchers in Australia to screen We are currently trying to determine Which ones are capable of wasps in both countries. All insects if this sub-bacterial organism is breaching our borders in the carry microbes, so we are looking present in New Zealand wasps, and future? What are the chances they to see what microbes wasps carry working with the Australians to find will establish in New Zealand? All in their guts. So far, the results out what it does (is it harmful, are key questions in our fight to have been disappointing. Wasps helpful or neither?). This organism prevent invasive species from do not have many bacteria in their may be our best chance to develop destroying our environment. guts and those they do have are a self-sustaining control for wasps Check out the list at http:// picked up from the environment, in New Zealand. www.issg.org/database probably with food. So, although we have been able to identify a Travis Glare The database is funded by La number of bacterium from wasp AgResearch Fondation TOTAL, and is part of the guts, no single species of bacteria [email protected] Global Invasive Species Database. 13 Stowaways No. 2 October 2002

Illegal immigrant arrives unprepared

An unwelcome immigrant sailed into the Marlborough Sounds last summer, but might not have been prepared for a long stay. The unusual wasp was spotted foraging around some flowers by a keen- eyed gardener at Waikawa Bay, near Picton. Aware that this large and fearsome-looking wasp was not of the normal variety, the intrepid gardener struck it down with her shoe and took it to the local Department of Conservation office.

The wasp, identified by Landcare Research at Nelson, was a female yellow oriental paper wasp, Polistes reason why this species has failed suggests the wasp arrived as a olivaceus. This large, yellowish to establish in New Zealand, hibernating queen aboard one of brown species is native to Asia, but despite several known incursions the overseas yachts that visited the has spread to many of the warmer in the past. A close relative, the marina over the summer months. parts of the world. It is widespread Asian paper wasp (Polistes Thankfully, it is unlikely that the around the Pacific region, where it chinensis), is established in the yellow oriental paper wasp would is known variously as the Pacific Marlborough region, but it survive the New Zealand climate, Island hornet, the Fiji hornet, and originates from more temperate but this incursion is a sharp the redbrown paper wasp. It is lands, and invariably nests in north- reminder of the biosecurity risk at renowned for its painful sting! facing sites to make full use of the all points of entry. The next sailor to sun’s warmth. jump ship may be better prepared. A search of the property where the wasp was found resulted in the The property on which the wasp Richard Toft discovery of a small nest, complete and nest were found overlooks the Landcare Research with four eggs. However, the small Waikawa Bay marina. This [email protected] position of the nest indicates that this immigrant was Invasive alien species unprepared for the New Richard Toft Zealand climate – it was Alien species: A species built in a cold, shady occurring outside its natural location under the eaves range is called an alien on the south side of the species. When that species is house. The yellow an agent of change and oriental paper wasp is threatens native biological adapted for warmer diversity it is known as an climates and has invasive alien species, or just developed a strategy of an invasive species. A new nesting in the shade to organism can change the protect its brood from the species diversity, and therefore heat of the tropical sun. the whole community, of its 14 This could be one The yellow oriental paper wasp found at Waikawa Bay adopted habitat. Stowaways No. 2 October 2002

Paper wasp heads south Argentine ants kill wasps

The Asian paper wasp, Polistes Argentine ants have invaded or were being consumed by ants. chinensis, is now well established Whangarei, and the ants are as Even more interesting was the in Central Otago. It was first aggressive as their reputation number of ants entering the nest. recorded in New Zealand in 1979 implies – taking over and killing an The ants had several nests at Whangaparaoa Peninsula, active wasp nest. themselves under the fallen and decaying banana leaves that form Auckland. By 1987 it had spread A German wasp nest had a dense mulch and detritus under as far south as Taumaranui and established in a cavity caused by the the palms. Napier, and by 1990 it had decay of an old palm rootstock, at the established in Nelson. Now base of one of my banana palms. I I monitored the nest for the next week records show it is capable of intended to deal with the wasp nest and a half, after which all wasp surviving in southern New Zealand. in early to mid-March when it would activity ceased. During this time ants be cooler and the wasps would, I continued to come and go from the hoped, be less active. nest entrance and I observed ants attached to wasps right up until all

Richard Toft However, when I went to poison the wasp activity ceased. nest (near the end of March), I found only the occasional wasp flying in I had not used any poison or other and out of the nest. I saw several wasp control during the active dead wasps outside the nest and wasp season, so ants were directly about six wasps were crawling on responsible for killing the wasp the ground near the nest entrance. nest. However, in my opinion, the In November 1999, three adult These wasps were struggling to wasp nest was probably on its last move as if affected by something. I legs anyway as it was near the end Asian paper wasps were observed noticed they had very stout brown of the wasp season, so the wasps in different parts of Alexandra. Since legs as if they were wearing socks. were probably a lot more then, these wasps have been found Crouching down, I noticed that the vulnerable to attack. each year from several locations in brown socks were actually several the town, where this species is now Peter Anderson Argentine ants attached to each leg. well established. It probably arrived Department of Conservation, as a stowaway from other parts of A closer inspection of the dead Northland New Zealand, as in April 1999, a wasps showed that they had been [email protected] large paper wasp nest was found on a property in Alexandra in a Invasion improves lakes container from Auckland. Lake Erie was once given up for south-western Lake Michigan. By Dunedin records are tenuous. An dead because human activity 1995, the population had active nest was reported there in added too much nutrient. increased 12-fold to six crayfish March 2001, but no individuals However, it is now clear of the per square metre. By filtering the were seen in that locality this organic matter that had been water, zebra mussels have year, and in October 2001 a choking it, thanks to zebra mussel increased the water clarity in hibernating female of unknown accidentally introduced from Lake Michigan. Because the reef origin was captured in a house in Europe to the Great Lakes in received more light, there was an Dunedin. While the Asian paper ballast water . increase in algae and in wasp may not yet be established organisms that eat algae, such as Crayfish numbers have in Dunedin, it probably could insects. This has led to increases dramatically increased at a natural establish there. in the number of crayfish, which reef in south-western Lake consume both algae and insects. Anthony C. Harris Michigan as a result of the zebra Otago Museum mussel invasion. Prior to the 1992 Graham Sandlant [email protected] invasion, crayfish were sparse in [email protected] 15 Stowaways No. 2 October 2002

Recent Publications

Barlow, N. D.; Beggs, J. R.; Barron, M. M. 2002: Dynamics of common wasps in New Zealand beech forests: a model with density dependence and weather. Journal of Animal Ecology 71: 663–671.

Barker, G. M. 2002: Gastropods as pests in New Zealand pastoral agriculture, with emphasis on Agriolimacidae, Arionidae and Milacidae. In: Barker, G. M. ed. Molluscs as crop pests. Wallingford, CABI Publishing. Pp. 361–423.

Barker, G. M. ed. 2002: Molluscs as crop pests. Wallingford, CABI Publishing. 468 p.

Barker, G. M.; Watts, C. 2002: Management of the invasive alien snail Cantareus aspersus on conservation land. DOC Science Internal Series 31. Wellington, Department of Conservation. 30 p.

Beggs, J. R.; Rees, J. S.; Harris, R. J. (in press): No evidence for the establishment of the wasp parasitoid, Sphecophaga vesparum burra (Cresson) (Hymenoptera: Ichneumonidae) at two sites in New Zealand. New Zealand Journal of Zoology.

Harris, R. J.; Berry, J. A. 2001: Confirmation of the establishment of three adventive ants (Hymenoptera: Formicidae) in New Zealand : Cardiocondyla minutior Forel, Ponera leae Forel, Mayriella abstinens Forel. New Zealand Entomologist 24: 53–56.

Harris, R. J. 2001: Argentine ant (Linepithema humile) and other adventive ants in New Zealand. DOC Science Internal Series 7. Wellington, Department of Conservation. 20 p.

Harris, R. J. 2002: Potential impact of the Argentine ant (Linepithema humile) in New Zealand and options for its control. Science for Conservation 196. Wellington, Department of Conservation. 36 p.

Raut, S. K.; Barker, G.M. 2002: Achatina fulica Bowdich and other achatinidae in tropical agriculture. In: Barker, G. M. ed. Molluscs as crop pests. Wallingford, CABI Publishing. Pp. 55–114.

Toft, R. J.; Harris, R. J.; Williams, P. A. 2001: Impacts of the weed Tradescantia fluminensis on insect communities in fragmented forests in New Zealand. Biological Conservation 102: 31–46.

Website More information on wasps and ants is available on our website: http://stowaways.landcareresearch.co.nz Stowaways is available on this site too.

Key contacts

Editor: Jacqueline Beggs Published by: Landcare Research Private Bag 6 Editorial assistance: Anne Austin/ Christine Bezar Nelson Layout: Nicolette Faville Phone: +64 3 548 1082 Cartoons: Anke Stomphorst This information may be copied and distributed to others without limitations, provided Landcare Research New Zealand Ltd 2002 and the source of the information is Drawings Rebecca Wagstaff acknowledged. Under no circumstances may a charge be made for this information without the express permission of Landcare Research New Zealand Ltd 2002. Production: Kerry Barton

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