They smell like sweet meat, destroy vacuum cleaners and wreak havoc on the countryside New Zealand.
The unusually wet summer brought joy to the farmers and grief to the residents, as a plague of cluster flies hit homes in the Canterbury and Vayrarapa regions.
Cluster flies – which are larger, more sluggish and smelly than the common housefly – do not pose a threat to human health, but may come as an undesirable surprise to those in whose homes they congregate.
One homeowner in Masterton said Stuff that it was the worst season for cluster flies in her 20 years living in the area, and that she needed to run several vacuum cleaners in several rooms twice a day to clear the onslaught.
“Sometimes it was so sad when you vacuum in the morning and they come back in the evening,” said Lisa Urbani. “You feel like you’re waging a losing battle. Once or twice I felt very depressed from all this. I thought, “God, will this ever end?”
Infection meant good business for pest control workers who were overwhelmed with requests for help.
Daniel Hyman of Guaranteed Pest Control in North Canterbury worked from dawn to dusk for several weeks and he needed to get in touch with his partner to keep up with demand.
“My alarm clock is basically my phone that rings in the mornings with customers who need to eliminate clusters,” he said. “It was absolutely insane.”
Hyman has never seen cluster flies in such numbers since starting work in the industry six years ago. “In the reports I received from farmers who have been farming in the area longer than I was alive, they have never seen them so bad,” he said.
An expert on errors has warned that such scenes may become more common as climate change prolongs the breeding season of insects.
“Insects like it when it’s warm, and they also like it when it’s wet,” said entomologist Dr. Paul Craddock. “If you see longer and warmer summer months, it means that the numbers in certain years may increase and begin to interact with people.”
Patricia Hilton of Allpest Pest Management in Central Otago said she couldn’t help but be impressed by the flying animals after ten years of working with them.
“They are so smart. They’re so insidious, ”she said.“ They hang out in the summer, just fly. Then when it cools down, they go inside and emit a sweet, meaty-smelling pheromone, so they [other flies] know that somewhere safe to pour for the winter.
“In the spring, they leave the building and mate, laying eggs in the soil. Then they hatch, hang out and spend a wonderful summer, and it all happens again.