Imagine a creature that can invade an entire country in just a few short years and transform its insect populations, eating almost all other insects it encounters. This is not science fiction but reality in the United Kingdom.
The harlequin ladybird, described as the most invasive ladybird on earth, was first found in 2004. Within months an enthusiast public mapped its alarming spread, collecting more than 20,000 records.
Seven of the UK’s eight native ladybirds are now in decline, and the ladybird is well established in the southern half of the UK.
In Australia we know that red fire ants have the potential to cause great harm to the natural environment, people and agriculture, but what other insects yet to arrive in Australia should we be worried about? The harlequin ladybird has established in New Zealand, but is not yet on Australia’s pest watch lists.
Could Australia fend off an insect armageddon?
Globally, only 70-100 insects have been specifically identified as likely to harm natural ecosystems. This is mostly likely an underestimate, due to the limited studies and interest. In Australia the knowledge is more limited.
The Invasive Species Council and Monash University School of Biological Sciences sought to address this by systematically identifying potentially harmful exotic insect species not yet established in Australia and their likely pathways of arrival. Securing a major grant from the Ian Potter Foundation and smaller grants from the Queensland and federal governments, our project began in 2017.
With the work set to finish in June 2019, some key messages are beginning to emerge.
After reviewing records of more than 2000 insects that could harm the natural environment, we identified around 240 species that have multiple independent sources of evidence showing they cause environmental harm. We drew on evidence collected about insects that have invaded countries elsewhere in the world, relying on published evidence, global databases and expert reviews.
About half of the species of concern were from the order of insects that includes ants, bees, and wasps, Hymenoptera.
How will they arrive?
Most insects of concern are likely to arrive on transport as contaminants or hitchhikers. In most cases this would be contaminated plant material (16 % of species), contaminated nursery material (16%) and the timber trade (8%).
Ants, the most common high risk insect invader, are also likely to be found on almost all potential pathways of introduction and spread.
A team of scientific experts reviewed the species to quantify the scale of the impacts based on published literature. Uncertainty and information gaps were recorded.
A set of foresighting exercises were also undertaken for a small number of insects to reveal the likely invasion scenarios if a species were to arrive in Australia – which environmental assets are they likely to impact and in what way? These outputs will be invaluable if we are to properly prepare for a high risk, damaging invasive insect.
All the information gathered will be compiled into an open source information platform, allowing the results to be interrogated, updated and shared. This will avoid the need to compile the information from the beginning when new information is collected and further risk reviews are undertaken.
A stakeholder workshop will be held during the middle of the year and a series of papers will be published in peer reviewed scientific journals.
This project was made possible by a major grant from the Ian Potter Foundation and supporting funding from the Department of Agriculture and Water Resources and the Queensland Department of Environment and Science. The project is especially grateful for the volunteer efforts of the expert review panel. The work was led by Professor Melodie McGeoch of the McGeoch Lab at the School of Biological Sciences, Monash University.