Invasion of the ants

Millions of argentine ants have invaded large parts of Tauranga _ including the main Mount Maunganui shopping strip where almost half of the 240 businesses are being pestered by "one of the world's 100 worst animal invaders".
The ants nest in the ground outside but forage inside in large persistent trails looking for food, water and shelter. They are prevalent in Otumoetai, Matua, Fraser St, Papamoa and Bayfair.
Environment Bay of Plenty's pest animal officer Donna Watchman said 80-100 shops in Mount Maunganui now had an argentine ant problem.
"Roughly from Mount Drury to the movie theatre ... on both sides of the road. And then 60 to 80 houses on May St and Victoria Rd, an area covering about 14 hectares," she said.
The World Conservation Union lists the ant as one of the world's 100 worst invasive alien species.
It has a fondness for crawling through people's beds at night, biting humans, and munching on small wildlife.
The aggressive ant was first discovered in Auckland in 1990 and has since spread to many parts of the country.
The ants turned up in the Bay in 1998 at Port of Tauranga, industrial areas in Mount Maunganui and in several residential zones.
They were also found in shops in Bayfair but were treated and are no longer a problem there.
They have, however, recently been found in homes in the area.
Mrs Watchman said Environment BOP was unsure how the ants came to be in the Bay but said the usual method was via translocation of a nest or a queen ant _ which wander out of the nest and help to forage for food or walk to establish a new nest.
Port of Tauranga operations manager Nigel Drake said to his knowledge the port had not had any area identified as being a problem with ants.
"On occasions they [MAF and Environment BOP] do come round and test for them," he confirmed.
While it is easy to confuse the ant with other household pest ants, it is distinguishable by its honey-brown colour, rather than being black like other ants.
The ants can't sting but some people react to their bite _ which they are capable of delivering if agitated or trapped in clothing.
The ants are not poisonous and do not have a sting. Another identifying indicator of the argentine ant is the sheer number on a property.
A native of Argentina and Brazil, the ant forms huge colonies with multiple queens.
Les Creswell, manager of Mainstreet Mount Maunganui, said representatives of Environment BOP had been guest speakers at last week's Business Breakfast.
He said shopowners were grateful for the regional council's assistance in helping co-ordinate control of the pest.
Some shopowners and residents in Mount Maunganui had been upset because they had treated the ant, only to have it reappear because their neighbours had not acted.
Mr Creswell said that to his knowledge it was the first time the argentine ants had hit Mount Maunganui's shopping centre.
He said the first sign of the ants was in December. He had also been fielding calls from nearby residents who were concerned about the presence of the ant colonies.
"It's pretty devastating in what the ants can do and they can breed prolifically," he said.
In the worst-case scenario, the ants can invade people's homes and Mrs Watchman said she had heard of the ants streaming through peoples' beds at night.
Large colonies can also mean people are unable to enjoy gardening or sitting outside in summer. They displace native ant species and pose a threat to wildlife as they monopolise pollen and nectar resources and have the gruesome potential to eat nestlings.
Mrs Watchman said she had seen them eating a baby sparrow while it was still alive.
"Their impacts on humans are financial as well as stressful.
"Loss of ability to sit outside and eat, loss of food contaminated and eaten by the ants, and loss of sleep due to their annoying habit of trailing into beds occasionally," she said.
The only effective way to control an infestation is by using Xstinguish bait, laid on the ground every 1.5-2.5m.
The treatment is safe for humans and cats or dogs, although animals do like the taste of it and should be kept inside for 6-8 hours when the bait is laid to give the ants time to eat it.
People wanting to control the ant should contact Environment BOP on 0800 368 267.