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.
Three very good dogs – named Bayar, Judd and Sasha – have sniffed out the endangered Alpine Stonefly, one of the smallest animals a dog has been trained to successfully detect in its natural habitat.
The conservation of threatened species is frequently hampered by the lack of relevant data on their distributions. This is particularly true for insects, where the difficulty of garnering simple information means the threatened status of many species remains unrecognised and unmanaged.
In alpine areas there is a pressing need for innovative methods to better reveal the distribution and abundance of threatened insects.
Alpine regions rely on cool temperatures, and since climate change will bring warmer weather and lower rainfalls, insects like the Alpine Stonefly, which lives in the alpine freshwater system, will struggle to survive.
And while insects might not be appealing to everyone, they are extremely important for ecosystem function.
Traditional survey detection methods are often labour intensive, and hard-to-find species provide limited information. This is where the labrador, border collie and samoyed came to the rescue.
La Trobe’s Anthrozoology Research Group Dog Lab in Bendigo, Victoria have been training a pool of local community volunteers and their dogs in conservation detection to use with environmental DNA sampling. Using both environmental DNA and detection dogs has the potential to generate a lot of meaningful data on these threatened stoneflies.
For seven weeks in a special program, dogs were trained to memorise the odour of the Alpine Stonefly (Thaumatoperla alpina), a threatened but iconic insect in the high plains.
The dogs have previously been trained to sniff out animal nests or faeces but not an animal itself, so this was a new approach and an Australian first.
Stoneflies are hard to catch
The Alpine Stonefly are brightly coloured aquatic insects and are difficult to find, especially as larvae in water where they live as predators for up to two years in the streams on the Bogong High Plains, Mount Buller-Mount Stirling, Mt Baw Baw and the Yarra Ranges.
They often burrow underneath cobbles, boulders and into the stream bed while the adults only emerge from the water for a few months between January and April to reproduce.
With all this in mind, it’s easy to understand why traditional detection methods can be time consuming and often ineffective.
We predominately focused on the endangered Alpine Stonefly, found across the Bogong High Plains. Their restricted distribution and habitat made them an ideal candidate to trial detection dogs and environmental DNA techniques.
How dogs and environmental DNA help
We collected water samples from across the Bogong High Plains, Mount Buller and Mount Stirling with trace DNA, such as cells shed from the insect. The ability to quickly take these samples from a broad area to indicate the presence of a species is important to understand distribution. But this approach limits the amount of ecological information that is gathered.
Initial training introduced the dogs to the odour of the Alpine Stonefly in a controlled laboratory setting. Then they graduated from the laboratory to small areas of bushland to search for the insect.
Once the dogs successfully completed their training, it was time to trial the dogs in the alpine environment and survey Alpine Stoneflies in their natural environment.
The trial was conducted at Falls Creek with the dogs’ three volunteer handlers. And the surveys were successful, with all three dogs finding Alpine Stoneflies in their natural habitats.
So could this success be transferred to a similar species?
Absolutely. In preliminary trials, Bayar, Judd and Sasha detected the Stirling Stonefly, a related species of Thaumatoperla that lives in Mount Buller and Mount Stirling, suggesting detection dogs can transfer their conservation training from one species to another.
This is a great find as it means this technique can be used to survey yet another species of Thaumatoperla that lives in Mt Baw Baw and the Yarra Ranges.
Our research is showing that these new sampling techniques supporting conservation are an important part of keeping biodiversity protected in alpine regions.
Now that we’ve successfully trained three dogs, we’re hoping to secure funding to conduct future and more thorough surveys on the Alpine and Stirling Stonefly, and eventually on the third species of stonefly.
By developing creative techniques to detect these species, we boost our ability to document them and, importantly, to protect them.
Forget the apes, we live on “The Planet of the Beetles”. Welcome.
With an estimated 387,000 formally described species, beetles (Coleoptera) are the most species-rich of the five mega-diverse groups of insects. The others are wasps, ants and bees (Hymenoptera), flies (Diptera), true bugs (Hemiptera), and butterflies and moths (Lepidoptera).
Today’s publication of 103 new species of weevils from the Indonesian island of Sulawesi is a timely reminder that, after several hundred years of research, we have not even described half of the insect diversity out there. Not even close. Especially in the tropics.
Knowing what we have
Ideally, before we worry about what we are losing, it would be nice to know what we have.
Guesstimates of the number of beetle species on Earth suggest that only about one quarter of the species out there have been described.
Although most British species were described by the middle of the 19th century, in many parts of the world it is easy to find new species and will be for many decades, providing they hang on that long.
And it’s probably best to set aside the notion of cracking a bottle of champagne with every new species discovery. As writer Simon Barnes says, referring — in Ten Million Aliens: A Journey Through the Entire Animal Kingdom — to people who discover new species, “they’d be pissed all day”. If you work on weevils, you’d be comatose.
Alexander Riedel, a weevil specialist from Germany, and Indonesian museum curator Raden Pramesa Narakusumo are working on the Asia-Pacific weevil genus Trigonopterus.
These small weevils, mostly several millimetres long, are distributed from Samoa in the Pacific through northern Australia to Sumatra. Australian Trigonopterus (32 described species) are mainly restricted to subtropical and tropical rainforests of the east coast, north from around the Queensland/New South Wales border.
The authors’ latest paper describes 103 new species from Sulawesi (Celebes of old) including several they named after Asterix, Obelix and Idefix – principal characters in the French comic series The Adventures of Asterix.
Species names are always lower-case and the genus always begins with a capital: for example “Trigonopterus asterix Riedel”, named after Asterix. Italics are used to show that we are talking about a genus and/or species name. The author or authors primarily responsible for describing the species are traditionally appended to the end of the name.
A small greenish forest-dwelling species is named after Yoda of Star Wars fame, and several others after well-known biologists including Charles Darwin, James Watson and Francis Crick (the latter two identified the structure of DNA).
Naming is fun but hard
Naming species in novel ways is more common that you might think. Just this week one of 14 new northern Australian dung beetle species was named Lepanus sauroni Gunter & Weir, after, you guessed it, Sauron of Lord of the Rings fame. Part of the beetle’s abdomen resembles the Eye of Sauron.
Most of the new Trigonopterus (and Lepanus) species are named after the locality where they were discovered, their collector, or distinctive characters they might have.
You might imagine coming up with 103 new names would be relatively easy, but it’s not that simple. There were already 341 Trigonopterus described (mostly by Riedel and colleagues), and the new names have to be different. The names for new species of this genus described in the future, and there are hundreds more, will have to be different again.
Living in Melbourne, as I do, there are plenty of undescribed invertebrate species including, of course, weevils. If you know what you are doing, many of these are abundant and easy to find. Some may represent charismatic, colourful, fascinating or old evolutionary lineages. Many of these species are known and are preserved in national or international collections awaiting description, but plenty of others are unseen and uncollected.
Who cares? And why?
A widespread lack of enthusiasm for invertebrates translates to a broader lack of knowledge and engagement, and the inevitable “who cares anyway?”.
In Wonderful Life, author Stephen Jay Gould writes:
Classifications are theories about the basis of natural order, not dull catalogues compiled only to avoid chaos.
Describing species, and revealing what is where, fundamentally underlies major fields of biology like ecology, evolution and biogeography, contributing to a deeper understanding of the complexity of life on Earth.
If we’re to prevent the loss of major parts of our biodiversity to extinction, a deeper understanding of the planet’s numerically dominant invertebrate life is critical. Fortunately, there are those like the authors of these papers who follow their passion, and back it up with a lot of highly skilled work.
Insects are important wildlife often overlooked in urban habitats. What we do notice are the cockroaches, ants and mosquitoes in and around our homes. All too often we reach for the insect spray.
But not all insects are pests – a wide variety of them help keep our cities healthy. They pollinate plants, feed other wildlife, recycle our rubbish, and eat other insect pests. Insects are vital to our well-being.
Unfortunately, like many other wild animals, insects are under threat. A recent study warned that 40% of the world’s insect species face the prospect of extinction, amid threats such as climate change, habitat loss, and humanity’s overenthusiastic use of synthetic chemicals.
Australians use large amounts of pesticides to tackle creepy crawlies in their homes and gardens. But our fondness for fly spray has potentially serious impacts on urban ecosystems and public health.
We need a more sustainable way to deal with urban insect pests. Our recently published article in the Journal of Pest Science outlines some of the ways to do it.
What’s wrong with pesticides anyway?
Since becoming publicly available in the 1950s, insect sprays have been a popular way to deal with cockroaches, flies, moths, and ants around the home and backyard, and are also widely used by local councils to keep pests at bay. But what may have been effective in the past won’t necessarily work in the future, or may have unintended consequences.
Many pests, such as mosquitoes, are now becoming resistant to commonly used products. In parts of the world affected by diseases such as dengue, this jeopardises our ability to control outbreaks.
Another, perhaps wider, problem is that indiscriminate use of insecticides can kill more than just pests. Many species on which we rely for keeping our backyard gardens, bushland, wetlands and parks healthy can become collateral damage. This includes predatory species that can themselves help keep pests under control. As pest species often reproduce faster than their predators (a pattern that’s likely to be reinforced by climate change), we can get trapped in a cycle in which pest numbers bounce back higher than ever.
How do we do things differently?
Fortunately, there are alternatives to chemical pest control that don’t harm your household or the environment. For centuries, sustainable agriculture systems have used environmentally friendly approaches, and city-dwellers can take a leaf from their books.
Integrated pest management is one such sustainable approach. It focuses on prevention rather than treatment, and uses environmentally friendly options such as biological control (using predators to eat pests) to safeguard crops. Chemical insecticides are used only as a last resort.
There are many other farming practices that support sustainable pest control; these focus on behavioural change such as keeping areas clean, or simple physical controls such as fly mesh or netting around fruit trees.
Adopting these methods for urban pest control isn’t necessarily straightforward. There might be local regulations on particular pest control activities, or simply a lack of knowledge about urban pest ecology.
For urgent pest situations, it may be more expensive and time-consuming to set up a biological control program than to arrange the spraying of an insecticide. Insecticides take effect immediately, whereas biological control takes longer to have an effect. Prevention, the cornerstone of integrated pest management, requires careful planning before pests become a nuisance.
The goal of integrated pest management is not to eliminate insect pests entirely, but rather to reduce their numbers to the point at which they no longer cause a problem. By this logic, chemical insecticides should only be used if the economic damage caused by the pests outweighs the cost of the chemicals. If you hate the idea of a single cockroach living anywhere nearby, this might require you to adjust your mindset.
What can I do at home?
Don’t give pests opportunities. Be mindful of how we produce and dispose of waste. Flies and cockroaches thrive in our rubbish, but they can be effectively managed by ensuring that food waste is stored in insect-proof containers, recycled, or properly disposed of. Don’t leave buckets of water around the backyard, as this invites mosquitoes to breed.
Don’t open your door to pests. Seal cracks and crevices in the outside of your house, and ensure there are screens on your doors and windows.
Support the animals that control insect pests – they’ll do the hard work for you! In particular, don’t be so quick to kill spiders and wasps, because they prey on pests in your home and garden.
What can we do as a community?
Urban communities can learn a lot from sustainable farming. First, there needs to be better education and support provided to the public and policy makers. Workshops run by local councils and information sessions with local gardening groups are a great way to start.
We can also work together to help debunk the popular myth that most insects are damaging or unwanted pests. Reaching for the fly spray might be easy, but remember you may end up killing friends as well as foes.
Lizzy Lowe, Postdoctoral researcher, Macquarie University; Cameron Webb, Clinical Lecturer and Principal Hospital Scientist, University of Sydney; Manu Saunders, Research fellow, University of New England, and Tanya Latty, Senior Lecturer, School of Life and Environmental Sciences, University of Sydney
But a global review of insect research has found another casualty: 40% of insect species are declining and a third are endangered. It confirms what many have been suspecting: in Australia and around the world, arthropods – which include insects, spiders, centipedes and the like — appear to be in trouble.
The global review comes hard on the heels of research published in the Proceedings of the National Academy of Sciences USA that suggests a potent link between intensifying heat waves and stunning declines in the abundance of arthropods.
If that study’s findings are broadly valid – something still far from certain – it has chilling implications for global biodiversity.
In the mid-1970s, researchers on the Caribbean island of Puerto Rico conducted a large-scale study to measure the total biomass (living mass) of insects and other arthropods in the island’s intact rainforests, using sweep nets and sticky-traps.
Four decades later, another research team returned to the island and repeated the study using identical methods and the same locations. To their surprise, they found that arthropod biomass was just one-eighth to one-sixtieth of that in the 1970s – a shocking collapse overall.
And the carnage didn’t end there. The team found that a bevy of arthropod-eating lizards, birds and frogs had fallen sharply in abundance as well.
In the minds of many ecologists, a widespread collapse of arthropods could be downright apocalyptic. Arthropods pollinate some of our most important food crops and thousands of wild plant species, disperse seeds, recycle nutrients and form key links in food chains that sustain entire webs of life.
This ecological ubiquity arises because arthropods are so abundant and diverse, comprising at least two-thirds of all known species on Earth. In the 1940s, evolutionary biologist J. B. S. Haldane quipped that “God has an inordinate fondness for beetles.” Humans might think we rule the world, but the planet really belongs to arthropods.
Killer heat waves
The researchers who documented the arthropod collapse in Puerto Rico considered a variety of possible causes, including pesticides and habitat disruption. But the evidence kept pointing to another driver: rising temperatures.
Weather stations in Puerto Rico indicate that temperatures there have risen progressively in the past several decades – by 2℃ on average.
But the researchers are far less worried about a gradual increase in temperature than the intensification of heat waves—which have risen markedly in Puerto Rico. This is because nearly all living species have thresholds of temperature tolerance.
For example, research in Australia has shown that at 41℃, flying foxes become badly heat-stressed, struggling to find shade and flapping their wings desperately to stay cool.
But nudge the thermometer up just one more degree, to 42℃, and the bats suddenly die.
In November, heat waves that peaked above 42℃ in north Queensland killed off almost a third of the region’s Spectacled Flying Foxes. The ground beneath bat colonies was littered with tens of thousands of dead animals. Dedicated animal carers could only save a small fraction of the dying bats.
The El Niño connection
El Niño events – fluctuations in Pacific sea-surface temperatures that drive multi-year variations in weather across large swaths of the planet – are also part of this story. New research appears to be resolving longstanding uncertainties about El Niños and global warming.
Recent studies published in Nature and Geophysical Research Letters suggest global warming will in fact intensify El Niños – causing affected areas to suffer even more intensively from droughts and heat waves.
And this ties back to Puerto Rico, because the researchers there believe a series of unusually intense El Niño heatwaves were the cause the arthropod Armageddon. If they’re right then global warming was the gun, but El Niño pulled the trigger.
Beyond heat waves
Puerto Rico is certainly not the only place on Earth that has suffered severe declines in arthropods. Robust studies in Europe, North America, Australia and other locales have revealed big arthropod declines as well.
And while climatic factors have contributed to some of these declines, it’s clear that many other environmental changes, such as habitat disruption, pesticides, introduced pathogens and light pollution, are also taking heavy tolls.
So, at a planetary scale, arthropods are suffering from a wide variety of environmental insults. There’s no single reason why their populations are collapsing.
The bottom line is: we’re changing our world in many different ways at once. And the myriad little creatures that play so many critical roles in the fabric of life are struggling to survive the onslaught.