Each year, from September to mid-October, the tiny and very precious mountain pygmy-possums arise from their months of hibernation under the snow and begin feasting on billions of bogong moths that migrate from Queensland to Victoria’s alpine region.
But for the past two springs, moth numbers have collapsed from around 4.4 billion in alpine areas to an almost undetectable number of individuals. And the mountain pygmy-possums went hungry, dramatically affecting breeding success among the last remaining 2,000 that live in the wild.
This year’s migration of bogong moths to the possums’ alpine home is crucial for the critically endangered mountain pygmy-possums. That’s why we’re asking you to do two simple things: turn off your lights at night, and if you see a bogong moth, take a picture.
What’s happened to the moths?
We don’t know exactly why the moths are not making it to their summer alpine destination. It’s likely extreme drought, pesticides and changes in agricultural practices are all major factors. However, scientists believe that because moths use both the Earth’s magnetic field and visual cues on the horizon to navigate, light pollution from urban centres can confuse the moths and stall their journey.
Some of the greatest beacons on their path are Parliament House and Canberra’s bright surrounds. Both parliamentarians and the general public are being asked to turn unnecessary outdoor lights off from September 1 to October 31, as part of the Lights Off for Moths campaign.
Artificial night lighting has dramatically changed the nocturnal environment. In urban environments, the soft glow of moonlight is overpowered by bright streetlights, security lights and car headlamps. These light sources can be more than 1,000 times as bright as moonlight, and their biological impact is increasingly visible and widespread.
One of the most obvious impacts of artificial light at night is that it can attract animals (sometimes fatally). While a “moth to a flame” may be somewhat poetic, when one moth becomes hundreds, or potentially thousands, the ecological impact may be catastrophic. Current global lighting practices may be creating this very scenario.
Recent evidence links the presence of artificial light at night with large-scale deaths and shifts in nocturnal migration patterns in birds. In insects, artificial night lighting disrupts nocturnal pollination networks and is strongly linked with observed mass declines in insect (and particularly moth) populations.
No moths means hungry possums
When a species like bogong moths decline, it has huge ramifications. Insects in particular are vital pillars supporting whole ecosystems – without bees and other insect pollinators, for example, we risk the extinction of our flowering plants. Many birds, reptiles and mammals depend on insects as part of their diet.
For mountain pygmy possums, the fatty, nutrient-rich bounty of bogong moths arrives right as they are waking up in the spring. They are one of the only Australian mammals that hibernate, and can spend up to seven months sleeping under the alpine snow.
The possums awake ravenously hungry, and devour the bogong moths to regain crucial fat stores. Without the moths there at the right time, the possums struggle to secure enough energy to breed successfully.
Snap that moth
Alongside the Lights Off for Moths campaign, Zoos Victoria has launched Moth Tracker, an app that allows Australians to photograph and log any potential sightings of migrating bogong moths.
Moth Tracker, which can be accessed through any laptop or smartphone, is adapted from the popular Southern Right Whale watching app in collaboration with Federation University and Victorian conversation network SWIFFT.
Bogong moths migrate from their winter breeding grounds throughout Queensland, New South Wales and western Victoria in search of cooler climates for the spring and summer in the Victorian and NSW Alpine regions where the mountain pygmy-possums live.
Before they become moths, the larvae look like tiny, shiny brown capsules and are commonly referred to as cutworm. Migratory bogong moths are dark brown, with two lighter spots on each wing. They are small, only about the length of a paper clip. During the day they’re often seen grouped together like roof tiles. At night, they are more active and flying around.
If you see a bogong moth (or something you think might be a bogong month), we need you to take a photograph and log the location, day and time with Moth Tracker. Scientists will use the data to determine whether any moths are making their way to the precious, and very hungry, possums that are just starting to wake from their winter hibernation.
The Victorian Mountain Pygmy-possum Recovery Team, together with partner organisations, is also investigating options for interventions in the wild if needed. These may include a world-first airdropping of “bogong balls” to feed the hungry possums, as well as improving habitat connectivity and captive measures to support populations through the breeding season.
But with unnecessary outdoor lights switched off and citizen scientists looking out for bogong moths, there is still hope for the mountain pygmy-possums.
In wealthy societies we’ve become increasingly picky about what we eat. The “wrong” fruits and vegetables, the “wrong” animal parts, and the “wrong” animals inspire varying degrees of “yuck”.
Our repugnance at fruit and vegetables that fail to meet unblemished ideals means up to half of all produce is thrown away. Our distaste at anything other than certain choice cuts from certain animals means the same thing with cows and other livestock slaughtered for food. As for eating things like insects – perfectly good in some cultures – forget about it.
Disgust has its advantages. Its origins likely lie in the basic survival benefit of avoiding anything that smells or tastes bad. But disgust may also be an impediment to many of us adopting more sustainable lifestyles – from eating alternative sources of protein to drinking recycled water.
We set out to answer this by getting a better grip on how disgust works, focusing on disgust in everyday food choices, rather than aversions to the unknown or unfamiliar.
Our research suggests some disgust responses, once set early in childhood, are hard to shift.
But responses involving culturally conditioned ideas of what is “natural” may be modified over time.
Don’t eat that!
Disgust likely began as a powerful “basic” emotional reaction that evolved to steer us away from (and literally eject) potential contaminants – food that smelled and tasted bad. You can think of it as originally being a “don’t eat that” emotion.
The disgust system tends to be “conservative” – rejecting valid sources of possible nutrition that have characteristics implying they might be risky, and guiding us towards food choices that are ostensibly safer. Research by University of British Columbia psychologist Mark Schaller and colleagues suggests people who live in areas with historically high rates of disease not only have stricter food preparation rules but more “conservative” cultural traditions generally.
Is is unclear exactly how or when individual templates for what is disgusting are set, but generally what is seen as “disgusting” is set relatively early in life. Culture, learning and development all help shape disgust.
It’s just not natural!
In our study, we showed 510 adults pairs of “normal” and “alternative” products via an online survey, and asked them how much they would be willing to pay for the alternatives. We also asked them to rate which product was tastier, healthier, more natural, visually appealing and nutritious. Product pairs included:
- shiny and typically shaped fruits and vegetables vs knobbly, blotchy, gnarled and multi-limbed examples.
- plant protein foods vs insect-based foods
- standard drinks vs drinks with ingredients reclaimed from sewage
- standard medicines vs medicines with ingredients extracted from sewage.
Our results show that, even after statistically adjusting for obvious factors like pro-environmental attitudes, those with a greater “disgust propensity” are less willing to consume atypical (weird-looking) products.
This may seem rather obvious but most prior studies have muddled a food’s “novelty” with its possible disgusting properties (by asking people, for example, whether they’d eat bugs). By asking about really common fruits and vegetables, our study shows just how far disgust may reach in influencing what we consume.
As importantly, our results suggest evaluations of a product’s perceived naturalness, taste, health risk, and visual appeal “explains” about half of the disgust effect.
In particular, lack of perceived “naturalness” was a frequently reason for unwillingness to pay for product alternatives. This result was in line with previous studies that have looked attitudes to eating insects or lab-grown meat. This is a promising area for social marketing.
Given evidence about how much of what we consider disgusting is cultural and learned, marketing campaigns could help shift attitudes about what is “natural”. It has been done before. Consider this advertisement to naturalise sugar consumption.
Thinking differently about emotion-eliciting stimuli is termed “reappraisal”. Reappraisal has been shown to reduce disgust effects among those with obsessive compulsive disorder. Desensitisation (repeated exposures) seems less effective in reducing disgust (versus fear) among people with diagnosed phobias, but it may work better among the general population.
Of course, such speculations remain untested and their ultimate success remains unclear.
But it wasn’t so long ago that Western consumers turned their noses up at fermented foods, and the notion of “friendly bacteria” made as much sense as “friendly fire”. More than a decade ago the residents of a drought-stricken Australian town voted against recycling sewage for drinking water. Now the residents of an Australian city accept recycled sewage being pumped back into the city’s groundwater.
Given time, circumstance and a little nudging, a future meal at your favourite Thai restaurant may well involve ordering a plate of insects.
More than A$400 million of government funding is being invested in the latest round of the fire ant program in the hope of eradicating the invasive pests by 2027.
The claims are denied by Graeme Dudgeon, the new general manager of Queensland Government’s National Red Imported Fire Ant Eradication Program.
Fire ants are native to South America but nests were first discovered in Brisbane in 2001. It’s thought they arrived via shipping at the Port of Brisbane.
They’re regarded as one of the world’s worst invasive species and have a painful bite which is why the Queensland Government has been trying to wipe them out here.
Is eradication possible?
An independent review in 2016 found the fire ants were confined to a region of south east Queensland and said there was an opportunity to eradicate the pests.
But the latest debate raises the question of whether eradication is the best plan, or would further containing the spread of the fire ants be a more practicable solution?
To achieve its aim of eradicating the fire ant problem, the program needs to progressively shrink the invasion.
If the invasion is shrinking too slowly (or is expanding), eradication won’t be achieved by 2027. Without ongoing monitoring of the invasion’s size, the program might be failing without the general public knowing.
But knowing the fire ant invasion’s size isn’t easy because there isn’t enough funding to survey all locations that might have them.
Estimates of the invasion
Using records of past fire ant detections, we have demonstrated how to estimate the invasion’s size when only part of the managed area is surveyed.
If this approach to estimating the invasion boundary is applied each year during the current program, we could estimate whether the invasion is shrinking fast enough to be gone by 2027.
The importance of this issue demands a rigorous scientific analysis using transparent data and methods. Without this, anecdotal evidence that the current invasion is spreading is all we have to indicate whether eradication efforts are failing.
The size of the fire ant invasion should not only be measured in terms of the total area within its estimated boundary but also the density of nests within this area.
Eradication won’t be achieved if both the invasion boundary and the density within it are increasing. This straightforward test to determine whether the program is failing has not yet been applied.
But such a test could be done if updated records of the fire ant invasion are regularly made available to allow for periodic estimation of updated maps of the invasion.
Never give up
Even if eradication by 2027 is unlikely, this does not mean we should give up, provided future control efforts can contain the invasion at an affordable cost.
If the current program fails to eradicate the fire ants, it may still set the stage for effective long-term containment of the invasion.
A poor outcome will result if current management efforts are spread thinly over the infested area, reducing the density of nests but not eradicating them from any suburbs.
A better outcome would involve shrinking the infested area, that is, eradicating the ants from many or most suburbs, so that subsequent containment efforts can focus resources on a smaller area.
Is it still early enough in Australia to shrink the fire ant invasion to a manageably small area and thereby protect most homes and most of the environment for a long time? The required information to answer this question is not yet available.
But if Queensland’s eradication program has substantially slowed the spread so far, this provides confidence that continuing the program could effectively suppress the invasion. If so, we need to estimate what it will cost to keep out fire ants from most homes and most of the environment for a long time.
It’s often claimed that removing the last 1% of invaders costs as much as removing the previous 99%. If the current program removes all ants from most areas by 2027, this may provide large benefits without the extra cost of finding the last few ants in all infested areas.
Even if we do eradicate fire ants this time, it’s almost certain they will be back because they can readily hitchhike rides on ships.
So if governments can keep fire ant numbers down through ongoing containment, a lot of people and a lot of native species will benefit.
Have you ever seen a fairy? They exist, and may very well be in your garden. But you would need a high-powered microscope to spot the dainty creatures.
Fairy wasps (family Mymaridae) are tiny, feathery-winged parasitoid wasps. They’re often called fairy flies, which is a misnomer. The Mymaridae family includes the smallest known insects in the world. Most species are less than 1mm long – smaller than the average pinhead.
But two species in particular have the record for being the smallest insects in the world. Measuring 0.15-0.19mm, the smallest recorded winged insects are female Kikiki huna.
Not much is known of K. huna’s ecology, but the species was first discovered in Hawai’i (the scientific name is made from Hawaiian words for “tiny bit”). Since then, specimens have been recorded from Western Australia and South and Central America, suggesting the species could be distributed much more widely.
In 2013, another closely related species was discovered in Costa Rica and named Tinkerbella nana, after Peter Pan’s fairy friend.
The smallest known insect of all, at around 0.13mm, is a wingless male specimen of another fairy wasp, Dicopomorpha echmepterygis, found in the United States. Many insect species are sexually dimorphic, meaning males and females can look so different they may be confused as different species. For this fairy wasp, females are much larger than the record-breaking males, and have wings.
Eggs in eggs, wheels within wheels
All fairy wasp larvae are parasites. Adult females search for the eggs of other insects in sheltered places, such as under leaves or in leaf litter. When she finds a stash, she lays her own eggs inside the other eggs – an indication of just how tiny these wasps are! The wasp larva uses the nutrients from the egg to develop, killing the other insect in the process, before emerging through a tiny hole in the egg surface. The BBC captured this process in mesmerising underwater footage in 2017.
Adults only live for a couple of days to reproduce and start the cycle again. In fact, some males never leave the egg they develop in – as soon as they emerge from their own egg within an egg, they mate with a female and die.
Despite their diminutive size, fairy wasps pack a punch when it comes to impact. Their dependence on other insects to complete their life cycle means they play an important role in controlling populations of many other insects.
Scientists don’t think these wasps have strong preferences about their host species, which means they seem to pick whatever eggs are available. But very little is known of the ecology of most species, so it is hard to know for certain.
Most of the known records of fairy wasps have emerged from eggs of Hemiptera species, the group of sucking bugs that includes planthoppers and aphids. But other hosts are known to include thrips (Thysanoptera), beetles (Coleoptera), and psocid (Psocoptera).
The smallest insect in the world, D. echmepterygis, was reared from eggs of a psocid, or barklouse species – another group of small insects that is often overlooked. Barklice and booklice, also called psocids, are in the order Psocoptera; barklice usually feed on lichen and algae on tree trunks, while their cousins the booklice are often found feeding on mould inside book bindings in old libraries.
Other fairy wasp species have become valued for their important role as biological control agents in agricultural systems. Mymarids can control many damaging economic pests, including the glassy-winged sharpshooter, and weevil and sucking bug pests of eucalypt plantations. Many other associations remain to be discovered.
Fairy wasps are a fascinating example of how much biodiversity is still undiscovered. With so much focus on larger, or more charismatic species, the tiny world of the smallest animals on Earth goes by unnoticed.
We still have much to learn about the ecology and life history of minuscule fairy wasps. Most of us would walk past one nearly every day without noticing. But we can support them without seeing them. Like many other flying insects, adults need sugar from floral nectar or insect honeydew for their energy.
This means that encouraging flowering plants to grow in and around crop fields can help production. These wild floral resources support populations of many beneficial insects, including fairy wasps, making them more effective as biological control agents. And, just like many other beneficial insects, pesticides can kill fairy wasps, or make them less effective at controlling other pests.
The same principle goes for gardens. Next time you find a pesky insect herbivore munching on your plants, consider an experiment: let them be and see how long it takes before fairies have moved into the bottom of your garden.
The Queensland city of Rockhampton was free of dengue for decades. Now, a case of one of the most serious mosquito-borne diseases has authorities scratching their heads.
Over the past decade, dengue infections have tended to be isolated events in which international travellers have returned home with the disease. But the recent case seems to have been locally acquired, raising concerns that there could be more infected mosquitoes in the central Queensland town, or that other people may have been exposed to the bites of an infected mosquito.
What is dengue fever?
The illness known as dengue fever typically includes symptoms such as rash, fever, headache, joint pain, vomiting, diarrhoea, and abdominal pain. Symptoms can last for around a week or so. Four types of dengue virus cause the illness and they are spread by mosquito bites.
Once infected, people become immune to that specific dengue virus. However, they can still get sick from the other dengue viruses. Being infected by multiple dengue viruses can increase the risk of more severe symptoms, and even death.
Hundreds of millions of people are infected each year. It is estimated that 40% of the world’s population is at risk given the regions where the virus, and the mosquitoes that spread it, are active. This includes parts of Australia.
Only a handful of locally acquired cases have been reported around Cairns and Townsville in the past decade. All these cases have two things in common: the arrival of infected travellers and the presence of the “right” mosquitoes.
The dengue virus isn’t spread from person to person. A mosquito needs to bite an infected person, become infected, and then it may transmit the virus to a second person as they bite. If more people are infected, more mosquitoes can pick up the virus as they bite and, subsequently, the outbreak can spread further.
Why are mosquitoes important?
Australia has hundreds of different types of mosquitoes. Dozens can spread local pathogens, such as Ross River virus, but just one is capable of spreading exotic viruses such as dengue and Zika: Aedes aegypti.
Aedes aegypti breeds in water-holding containers around the home. It is one of the most invasive mosquitoes globally and is easily moved about by people through international travel. While these days the mosquito stows away in planes, historically it was just as readily moved about in water-filled barrels on sailing ships.
The spread of Aedes aegypti through Australia is the driving force in determining the nation’s future outbreak risk.
The mosquito was once widespread in coastal Australia but since the 1950s, it become limited to central and far north Queensland. We don’t really know why – there are many possible reasons for the retreat, but the important thing now is they don’t return to temperate regions of the country.
Authorities must be vigilant to monitor their spread and, where they’re currently found, building capacity to respond should cases of dengue be identified.
What happened in Rockhampton?
Last week, for the first time in decades, a locally acquired case of dengue was detected in Rockhampton, in central Queensland. The disease was found in someone who hasn’t travelled outside the region, which suggests they’ve been bitten locally by an infected mosquito.
This has prompted a full outbreak response to protect the community from any additional infected mosquitoes.
While the risk of dengue around central Queensland is considered lower than around Cairns or Townsville, authorities are well prepared to respond, with a variety of techniques including house-to-house mosquito surveillance and mosquito control to minimise the spread.
These approaches have been successful around Cairns and Townsville for many years and have helped avoid substantial outbreaks.
The coordinated response of local authorities, combined with the onset of cooler weather that will slow down mosquitoes, greatly reduces any risk of more cases occurring.
What can we do about dengue in the future?
Outbreaks of dengue remain a risk in areas with Aedes aegypti mosquitoes. There are also other mosquitoes, such as Aedes albopictus (the Asian tiger mosquito), that aren’t currently found on mainland Australia but may further increase risks should they arrive. Authorities need to be prepared to respond to the introductions of these mosquitoes.
While a changing climate may play a role in increasing the risk, increasing international travel, which represents pathways of introduction of “dengue mosquitoes” into new regions of Australia, may be of greater concern.
There is more that can be done, both locally and internationally. Researchers are working to develop a vaccine that protects against all four strains of dengue virus.
Others are tackling the mosquitoes themselves. Australian scientists have played a crucial role in using the Wolbachia bacteria, which spreads among Aedes aegypti and blocks transmission of dengue, to control the disease.
The objective is to raise the prevalence of the Wolbachia infections among local mosquitoes to a level that greatly reduces the likelihood of local dengue transmission.
Field studies have been successful in far north Queensland and may explain why so few local cases of dengue have been reported in recent years.
While future strategies may rely on emerging technologies and vaccines, simple measures such as minimising water-filled containers around our homes will reduce the number of mosquitoes and their potential to transmit disease.