Portuguese Millipede Invasion Prompts Research in New Zealand’s Capital
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A surge in Portuguese millipede sightings is causing concern for residents along Wellington’s South Coast, prompting scientists to investigate the extent of the infestation and potential control measures. The invertebrates have been reported invading homes in areas like Ōwhiro Bay, turning up in unexpected places such as shoes, bags, and even beds.
Growing Infestation and Resident Distress
The recent increase in millipede numbers has left some Wellington residents feeling overwhelmed. One resident described the ongoing battle against the pests as “mentally exhausting,” highlighting the psychological toll of constant removal efforts. “You sweep them up, bin them, and the next day they’re back,” a local explained. “If you crush them, they smell bad.”
The Portuguese millipede (Omatoiidae), native to Europe, has likely been present in the Wellington region for approximately two decades. However, little is currently known about the species’ ecological impact despite its growing prevalence.
Tracking the Spread and Understanding Defenses
Victoria University entomology professor Phil Lester explained that the millipedes were first identified in a transitional facility in Seaview before spreading to Wainuiomata and the South Coast. A key challenge in controlling the population lies in the millipedes’ natural defenses. According to Professor Lester, “Not a lot eats them. They have a natural defence chemical they excrete when they are attacked or when something does try and eat them that makes them really distasteful.”
Research Efforts Underway
To better understand the scope of the problem, ecology student Dan Moskovitz is leading a research project. The project utilizes bark mulch bags placed at 47 sites throughout the region, with the mulch sourced from Ōtari-Wilton’s Bush, to monitor millipede distribution over the next 18 months. “If we can get even some course-level detail on their distribution in Wellington and how fast they’re changing, that would be fantastic,” Moskovitz said. The research will also investigate whether the millipedes are competing with native invertebrate species.
Promising Biological Control Method
Scientists are exploring potential control methods, with early indications pointing to the effectiveness of nematodes – microscopic worms. These nematodes infiltrate the millipedes through natural openings, releasing bacteria that ultimately kill the host and allow the worms to reproduce. While nematodes are not expected to eradicate the millipede population entirely, researchers hope they can effectively prevent further spread.
The ongoing research represents a critical step in managing this emerging ecological challenge and mitigating the impact on Wellington communities.
