Norfolk Island’s largest native land snail Advena campbellii is one of the three Critically Endangered species
Land snails are underappreciated but play essential roles in recycling nutrients in soils and as food for many animals. Around 60 unique land snail species call Norfolk and Phillip Islands home. They come in a remarkable variety of shapes and colours but are facing threats from predators like rats and flatworms, and habitat loss. Currently, two species have become extinct while three species are Critically Endangered. Following the footsteps of Australian Museum researchers, PhD candidate Junn Kitt Foon of Western Sydney University is undertaking a three-year project to study:
(1) How are the last populations of these threatened snails genetically connected to each other?
(2) What habitats are best for native snails?
(3) How much are these snails affected by non-native predators?
(4) How might climate change affect these snails?
Answering these questions will hopefully help secure the long-term survival of these unique Norfolk and Phillip Island species. If you are keen to volunteer in future fieldwork or if you are a landowner interested to know what land snails can be found in the scrub on your land, please contact Junn by email: 22078036 AT SYMBOL student.westernsydney.edu.au or Junn.Foon AT SYMBOL Australian.Museum
We thank Junn Toon for this account of this important research.
The honey bee population on Norfolk Island is unique from a pest and disease perspective. No other honey bee population in the world has fewer pests and pathogens. This important finding was confirmed in 2022 by a survey by Dr John Roberts of CSIRO. The report recommended that ongoing surveillance in Norfolk Island as part of the National Bee Pest Surveillance Program be resourced. Read the report here. The report can also be found on the Department’s website: Norfolk Island bee pest survey 2021–2022. The Department has summarised the results as follows:
“Honey bees are an important part of the ecosystem and culture of Norfolk Island. Honey bees support food security through reliable pollination services as well as producing honey and hive products. Having access to up-to-date information on bee pests and diseases is critical to maintaining the Island’s bee biosecurity.
In December 2022 and April 2023, Dr John Roberts visited Norfolk Island to conduct surveys of the honey bee population. Under the guidance of Norfolk Island’s beekeepers, Dr Roberts collected samples from bees, honey and hives to test for pests and diseases. He sampled 67 bee colonies (approximately 50% of all managed colonies) and inspected and tested for 16 pests and diseases.
The key findings of the survey are:
Since the last 2012–14 survey, no new honey bee pests or diseases were detected in Norfolk Island honey bees.
All previously reported pests and diseases were detected, including
high prevalence and infection levels of the gut parasite, Nosema ceranae
high prevalence of Lake Sinai virus, a common bee virus group with no known disease
low detection of the lesser wax moth (Achroia gresella), a minor hive pest.
The honey bee population on Norfolk Island is unique from a pest and disease perspective. No other honey bee population in the world has fewer pests and pathogens.
The report made three recommendations:
Permit only commercial importation of certified irradiated honey into Norfolk Island.
Resource ongoing surveillance in Norfolk Island as part of the National Bee Pest Surveillance Program.
Registration for all Norfolk Island beekeepers and encouraging beekeepers to perform regular hive inspections in line with Australia’s Honey Bee Industry Biosecurity Code of Practice.
On Phillip Island, off Norfolk Island’s south side, the population of Phillip Island Centipedes (Cormocephalus coynei) can kill and eat up to 3,700 seabird chicks each year. Luke Halpin and colleagues tell the story in an article in The Conversation on 3 August 2021.
Giant bird-eating centipedes exist — and they’re surprisingly important for their ecosystem
Giant bird-eating centipedes may sound like something out of a science-fiction film — but they’re not. On tiny Phillip Island, part of the South Pacific’s Norfolk Island group, the Phillip Island centipede (Cormocephalus coynei) population can kill and eat up to 3,700 seabird chicks each year. And this is entirely natural. This unique creature endemic to Phillip Island has a diet consisting of an unusually large proportion of vertebrate animals including seabird chicks.
Phillip Island in the Norfolk Island group, with a valley of iconic Norfolk Island Pine trees. Luke Halpin
As large marine predators, seabirds usually sit at the top of the food chain. But our new study, published in The American Naturalist, demonstrates this isn’t always the case. We show how large, predatory arthropods can play an important role in the food webs of island ecosystems. And the Phillip Island centipede achieves this through its highly varied diet.
A well-armed predator stirs in the night
This centipede can grow to almost one foot (or 30.5cm) in length. It is armed with a potent venom encased in two pincer-like appendages called “forcipules”, which it uses to immobilise its prey. Its body is protected by shield-like armoured plates that line each of the many segments that make up its length. On warm and humid nights, these strictly nocturnal arthropods hunt through thick leaf litter, navigating a labyrinth of seabird burrows peppered across the forest floor. A centipede on the prowl will use its two ultra-sensitive antennae to navigate as it seeks prey.
The centipede hunts an unexpectedly varied range of quarry, from crickets to seabird chicks, geckos and skinks. It even hunts fish — dropped by seabirds called black noddies (Anous minuta) that make their nests in the trees above.
A frightful discovery
Soon after we began our research on the ecology of Phillip Island’s burrowing seabirds, we discovered chicks of black-winged petrels (Pterodroma nigripennis) were falling prey to the Phillip Island centipede. We knew this needed further investigation, so we set out to unravel the mystery of this large arthropod’s dietary habits.
Black-winged petrel chick just prior to being weighed on Phillip Island. Trudy Chatwin
To find out what these centipedes were eating, we studied their feeding activities at night and recorded the prey species they were targeting. We also monitored petrel chicks in their burrow nests every few days, for months at a time. We eventually began to see consistent injury patterns among chicks that were killed. We even witnessed one centipede attacking and eating a chick. From the rates of predation we observed, we calculated that the Phillip Island centipede population can kill and eat between 2,109 and 3,724 petrel chicks each year. The black-winged petrels — of which there are up to 19,000 breeding pairs on the island — appear to be resilient to this level of predation.
Envenomation of a black-winged petrel nestling by a Phillip Island centipede. (Video by Daniel Terrington)
And the predation of black-winged petrels by Phillip Island centipedes is an entirely natural predator-prey relationship. By preying on vertebrates, the centipedes trap nutrients brought from the ocean by seabirds and distribute them around the island. In some sense, they’ve taken the place (or ecological niche) of predatory mammals, which are absent from the island.
Luke Halpin monitoring black-winged petrel chicks on Phillip Island. Trudy Chatwin
Restoration and recovery
Up until just a few decades ago the Phillip Island Centipede was very rare. In fact, it was only formally described as a species in 1984.
After an intensive search in 1980, only a few small individuals were found. The species’s rarity back then was most likely due to severely degraded habitats caused by pigs, goats and rabbits introduced by humans to the island. The removal of these invasive pests enabled black-winged petrels to colonise. Their population has since exploded and they’re now the most abundant of the 13 seabird species that breed on Phillip Island. They provide a high-quality food source for the Phillip Island centipede and have therefore likely helped centipede population to recover.
Black-winged petrels on Phillip Island are active both during the day and at night. (Video by Luke Halpin)
Ancient bone deposits in the soil suggest that prior to the black-winged petrel’s arrival, Phillip Island was home to large numbers of other small burrow-nesting seabird species. It’s likely the Phillip Island centipede preyed on these seabirds too. Now, thanks to the conservation efforts of Norfolk Island National Park, the island’s forest is regenerating alongside endemic species like the centipede, as well as the critically endangered Phillip Island hibiscus (Hibiscus insularis).
The endemic Phillip Island hibiscus. Luke Halpin
As a driver of nutrient transfer, the persistence of the Phillip Island centipede (and its healthy appetite) might just be key to the island’s ecosystem recovery. But we’ll need to do more research to fully understand the intricate links in this bustling food web.
Norfolk Island has an extremely healthy European bee population. The first European bees recorded on Norfolk Island were in the 1840s when the convict settlement was operational.
The Norfolk bees are free from European and American Foulbrood and we have no hive beetles or Varroa mite. The spores for European and American Foulbrood are able to survive in untreated honey and on bee equipment for at least 80 years. No importation of used bee equipment (which includes clothing and shoes) is allowed into Norfolk Island.
Unfortunately since 2016 (when Australia assumed control of Norfolk Island) 750g of untreated honey for personal use is allowed to be imported by anybody with the one proviso that it is “not to be fed to bees.”
To keep this bee population safe we requested that Norfolk Island become part of the Australian Sentinel Hive programme. As part of that programme we have set up sentinel hives at all the first points of entry on Norfolk Island. If there is an incursion of a pest or disease then these hives hopefully will be the first affected and that will give us a fighting chance to treat/eradicate any invader.
We monitor the sentinel hives on the first of each month and use different techniques to check for a variety of pests/diseases and this information is then immediately passed on to Plant Health Australia who collate all the information from all the sentinel hives scattered around first points of entry on mainland Australia.
We have put in a submission to the Commonwealth of Australia to have Norfolk Island declared a Bee Sanctuary but the response from the Commonwealth is that such a declaration is a State function and as Norfolk Island is a Territory not a State no sanctuary is possible.
A land snail listed more than 20 years ago as extinct was re-discovered in October 2020 by researchers from the Australian Museum. The Norfolk Island Flora and Fauna Society hosted a presentation on 22 October by Dr Isabel Hyman, supported by Dr Frank Köhler from the Museum and Brett Finlayson from Taronga Park Zoo. These investigators spent time during their visit surveying vegetation and plant debris in the parks and forests for these fascinating creatures. The ABC has the story.
Norfolk Island’s largest native land snail Advena campbellii is one of the three Critically Endangered species
