Fomentar una alianza mundial para el desarrollo

As hitchhiker species A. gracilipes and P. longicornis can be associated with any part of the fresh produce import pathway. Although commonly found in disturbed areas such as crop fields and orchards, they are urban pests also, so may be found nesting in or near buildings. Ants could be incidentally exported with Citrus. Both ant species (queens, small colonies or just workers) have been intercepted at the New Zealand border, frequently on fresh produce from the Pacific as well as empty sea containers and timber (Abbott et al. 2005; Harris and Abbott 2005).

Although it would be unlikely whole nests could be moved with fresh Citrus fruit, it is possible individual ants or small groups could find their way into the cartons prior to export, from within or around the packing house or storage areas.

Both species of ant have survived the shipping time of 6-8 days in the past (Abbott et al. 2005; Harris and Abbott 2005) therefore they will survive the flight time from Samoa to Auckland (about 4 hours) or shipping time of about 7 days.

It is considered the likelihood of entry for Anoplolepis gracilipes and Paratrechina longicornis is high.

15.4.2. Exposure assessment

Initially any ants arriving in produce are likely to move from the point where the boxes are opened because of the disturbance. They will move to an area where they can find shelter and food. Their mobility increases the likelihood of exposure.

Dispersal would most likely occur by human mediated movement.

15.4.3. Establishment assessment

Workers on their own cannot begin a colony as they are sterile.

A. gracilipes and P. longicornis have successfully spread and established outside of their native range and are well established in the Pacific. A single mated queen is sufficient to start a population if she arrives with enough fat reserves to locate a nest site and rear the first workers. The time of year is important as establishment is less likely in winter although a suitable microclimate (inside a building or glasshouse) could allow this.

Climate matching showed New Zealand has a low degree of similarity with sites where A. gracilipes has established. A. gracilipes is not as closely associated with buildings as is P. longicornis. It is a tropical/subtropical species and it may survive in hot microclimates in the far north of the North Island. However is is more likely New Zealand is too cold for

establishment of A. gracilipes (Abbott et al. 2005).

In 2004 a nest of P. longicornis was found and destroyed in Wellington (Harris and Abbott 2005). P. longicornis is a disturbance specialist and will readily nest in disturbed

environments, in or near buildings. It is likely to move into heated buildings if it finds the outdoors too cool (Harris and Abbott 2005; Nickerson and Barbara 2007).

The likelihood of establishment for A. gracilipes is low but non negligible. The likelihood of establishment for P. longicornis is high.

15.4.4. Consequence assessment

15.3.4.1 Economic impacts

A. gracilipes and P. longicornis are likely to be a nuisance in horticulture by tending and protecting honeydew secreting homoptera. A. gracilipes can be destructive by removing roots around plants (Abbot et al. 2005). Where abundant A. gracilipes has been known to to prey upon newborn newborn pigs, chickens, cats, rats, dogs and rabbits, and irritate by spraying formic acid (Haines et al. 1994).

As climate is a limiting factor A. gracilipes is unlikely to reach densities that would cause significant economic impacts. P. longicornis is likely to have a greater range and reach higher numbers, although also not likely to cause significant economic impact. However surveillance and response programmes are very costly.

The economic consequences of establishment of A. gracilipes and P. longicornis are considered to be medium and are therefore non-negligible.

15.3.4.2 Environmental impact

A. gracilipes, should it establish in hot microclimates could have a significant impact on indigenous fauna such as native land snails (see Abbott et al. 2005; Andersen 2000).

P. longicornis prefers disturbed environments so is not likely to establish in native habitats. In optimal climates this species is not ecologically dominant (Harris and Abbott 2005).

The environmental consequences of establishment of A. gracilipes are considered to be high. The environmental consequences of establishment of P. longicornis are considered to be low but non negligible.

15.3.4.3 Human health and social impact

In the Seychelles, in high densities, A. gracilipes is a serious household pest, a nuisance in public buildings and food processing establishments and a medical problem by entering open wounds, ears, eyes and noses (Abbott et al. 2005).

A. gracilipes has been known to cause formic acid burns on people, resulting in scarring (K. Abbott pers obs.: In Abbott et al. 2005).

P. longicornis is a pest in urban areas where it can become abundant indoors. P. longicornis may also transmit diseases. In three Brazilian hospitals it was the second most common species recorded and at least 20% of the foragers carried pathogenic bacteria (Fowler et al. 1993).

It is more frequently is known for being a nuisance in domestic situations when abundant. As climate is likely to have a moderating effect on establishment and spread of A. gracilipes and P. longicornis, the health or social consequences of entry and establishment is considered medium.

15.4.5. Risk estimation

The likelihood of Anoplolepis gracilipes and Paratrechina longicornis entering the country is high, exposure is medium and establishment low to high depending on the species. The consequences are low to high depending on the species. The risk estimate is non negligible therefore these two species of ant are classified as hazards in this commodity and risk management measures can be justified.

15.5. Risk management of Anoplolepis gracilipes and Paratrechina longicornis,