Welcome Asterix, Obelix and Yoda! Finding fun in the serious matter of discovering insects



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Do these look like Gauls to you? Three of the 103 new weevils identified in Indonesia were named after characters Asterix, Obelix and Idefix.
Alexander Riedel

Nick Porch, Deakin University

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).




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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.

This seems particularly important in light of recent media attention on the global loss of insects (which may or not be an “insectageddon”, depending on how you look at the data).

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.




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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.

Welcome weevils

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.

Asterix and Obelix don’t like the Romans much.

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).

103 new weevil species from Sulawesi: can you pick the differences between them all?
Alexander Riedel

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.




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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.The Conversation

Nick Porch, Senior Lecturer in Environmental Earth Science, Deakin University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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The battle against bugs: it’s time to end chemical warfare



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Does it really pay to spray?
Dmitry Syshchikov/Shutterstock

Lizzy Lowe, Macquarie University; Cameron Webb, University of Sydney; Manu Saunders, University of New England, and Tanya Latty, University of Sydney

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.




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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.

Many wasps are predatory and specialise in eating insects that can be pests around the home.
Manu Saunders



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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.

Spiders like this leaf curler will happily eat a range of pests, including ants, around your home.
jim-mclean/flickr



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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.The Conversation

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

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Climate change is killing off Earth’s little creatures



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A jumping spider, which uses sharp eyesight to hunt its prey.
ThomasShahan.com/Flickr, CC BY-SA

Bill Laurance, James Cook University

Climate change gets blamed for a lot of things these days: inundating small islands, fueling catastrophic fires, amping-up hurricanes and smashing Arctic sea ice.

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.




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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.

Our natural world depends on arthropods.
Steve Raubenstine/Pixabay

Arthropod Armageddon

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.

Insects are crucial in food webs for species such as this hummingbird.
Pixabay

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.

Bats die en-masse during a recent heatwave.

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.

Monarch butterflies are declining in the USA and Mexico, probably from habitat disruption.
Pixabay

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.




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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.The Conversation

Bill Laurance, Distinguished Research Professor and Australian Laureate, James Cook University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Drugs in bugs: 69 pharmaceuticals found in invertebrates living in Melbourne’s streams



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Thanks to their consumption of invertebrates, Melbourne platypus likely receive half the recommended human dose of anti-depressants every day.
Denise Illing

Erinn Richmond, Monash University and Mike Grace, Monash University

Pharmaceuticals from wastewater are making their way into aquatic invertebrates and spiders living in and next to Melbourne’s creeks, according to our study published today in Nature Communications.

We found pharmaceuticals in every bug we sampled – over 190 invertebrates – from six different streams. These included caddisfly larvae, midge larvae, snails and dragonfly larvae. We also found pharmaceuticals in spiders living in stream-side vegetation.

We found 69 different drugs in the bugs, including fluoxetine and mianserin (anti-depressants), fluconazole (an anti-fungal), and non-steroidal anti-inflamatories (NSAIDs), often used to treat arthritis.

While we don’t know how these drugs are affecting these invertebrates, we know from other studies pharmaceuticals do affect the lifecycles of other organisms.

We also calculated that animals that eat these aquatic invertebrates, such as platypus, would be receiving half the daily recommended dose of anti-depressants for humans.




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Drugs everywhere

We know wastewater is a contributing factor to pharmaceutical contamination in aquatic organisms, so we sampled from a range of streams with different wastewater inputs. These included a site just downstream of large-scale wastewater treatment facility, and areas with ageing septic systems.

Sassafrass Creek, one of the streams sampled in the study.
Erinn Richmond

We also included a stream within a national park to attempt to obtain samples we thought would be free of pharmaceuticals. We sampled aquatic invertebrates and stream-side spiders and tested them for 98 pharmaceutical compounds.

To our surprise, we found up to 69 different pharmaceuticals in aquatic invertebrates and up to 66 in riparian (streamside) spiders. Contamination was greatest downstream of the high capacity waste water treatment plant.

Moreover, every insect we sampled contained pharmaceuticals, including at the site in a national park, possibly due to septic systems in the drainage area of the stream that contribute small amounts of waste water.

The fact we detected drugs, admittedly in very low concentrations, in this seemingly pristine site suggests finding places “free” from pharmaceutical contamination may be difficult. Recent studies by other researchers detected pharmaceutical contamination in surface water in Antarctica and in national parks in the US.

We also found spiders living on the stream edge (the “riparian zone”), also contain a wide variety of pharmaceuticals in their tissues. These animals primarily consume adult insects and are an indication other animals that eat adult aquatic insects, such as birds, reptiles and bats, may also be exposed.

Spiders living in stream-side vegetation take up pharmaceuticals from the insects they eat.
Erinn Richmond

The dark side of our pharmaceutical use

We take and are prescribed pharmaceuticals to improve our quality of life. These medications are designed to be biologically active – they are meant to treat us; for example, we take paracetamol to alleviate a headache. For all the benefits drugs afford us, there is an often overlooked dark side to our extensive use of them.




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When we take a pharmaceutical, our bodies do not always use all of the drug and we excrete drug residues into our waste water and the drugs then move into our sewage system. Unfortunately, waste water treatment facilities are not always designed to, or are capable of, removing pharmaceuticals. So they’re often discharged into our streams, rivers and coastal waters.

Lead author, Erinn, sampling invertebrates in Brushby Creek.
Keralee Brown

We have known from many studies over almost two decades that the drugs we take are found in waterways around the world. There are thousands of drugs available, but very little is known about their occurrence and movement through aquatic food webs.

Our research team has previously studied the effects these pharmaceuticals have on organisms living in streams. For example, we found fluoxetine, a common anti-depressant, increased stream insect emergence (the important phase of an insects’ life where it metamorphoses from a stream dwelling larvae to an aerial adult).

We also found this antidepressant, and other drugs, alter the rates of photosynthesis in algae, the important base of stream food webs.

Happy platypus?

Platypus and trout live in or nearby the streams we studied. These animals feed almost exclusively on aquatic invertebrates. Although we did not directly sample trout or platypus, we were able to use previous studies on the feeding rates of these animals to estimate what proportion of a human daily dose of drugs they may be exposed just by eating the aquatic invertebrates we did measure in the streams we studied.

Based on these calculations, a platypus living in a creek receiving waste water could be exposed to over half of a human daily dose (per kg body weight) of antidepressants, just by eating aquatic invertebrates. Trout, too, would be exposed to these drugs, but would be exposed to a lower dose.

Studies have shown single drugs can alter the behaviour of fish, but just what consuming 69 different pharmaceutical compounds might do to a fish or platypus remains unknown and worthy of future research.

Global pharmaceutical use is increasing, with many benefits to humankind. However, our recent publication makes it clear pharmaceuticals are accumulating and moving through stream food webs and expose spiders, and likely birds, bats, fish, and platypus to a wide array of drugs. We are yet to fully understand the broader ecological consequences of this type of pharmaceutical contamination.

We know in humans, there are health risks associated with taking multiple drugs because of drug interactions. Is the same true for animals? Like so many studies, our research leaves us with many unanswered questions.

The one thing that is abundantly clear is the drugs we so frequently use are ending up in nature and are moving through food webs.

This article was co-authored by Emma Rosi, an aquatic ecologist at the Cary Institute of Ecosystem Studies.The Conversation

Erinn Richmond, Research Fellow, School of Chemistry, Monash University and Mike Grace, Associate Professor, Monash University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Insects that look like sticks, behave like fruit, and move like seeds



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Male spiny leaf insect, Extatosoma tiaratum.
James O’Hanlon, Author provided

James O’Hanlon, University of New England

The key to a stick insect’s survival may be allowing their eggs to be eaten and excreted by birds, according to new Japanese research.

Phasmatodea – more commonly known as stick insects – were so named because they genuinely look just like sticks.

While some stick insects do look like the classic stick – mottled brown with elongated limbs – others look remarkably like green leaves. They even have intricate leaf-like veins in their broad green wings.

Stick insects use camouflage to hide from predators.
Shutterstock

But these new findings show that not only do these insects look like plants, they also behave like them – by using birds to disperse their offspring.

Surprisingly, researchers led by Kenji Suetsugu of Kobe University found that stick insect eggs can actually survive being digested by birds, and in some cases still successfully hatch.

Young stick insects.
Shutterstock



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They fed three eggs from three stick insect species to their main bird predator, the brown-eared bulbul. Within three hours, 5-20% of these eggs had been defecated and were completely intact.

Even more impressively, a few of these eggs subsequently hatched. This leads us to ask what would happen if an adult female was eaten by a bird. Would the eggs inside of unlucky stick insect survive the bird’s digestive system and stand a chance of making it out at the other end?

Creative transportation

Plants have evolved ingenious ways of moving their seeds across large distances. Some seeds are carried by the wind or ocean currents, or by animals. Bushwalkers will be very familiar with prickly seeds designed to attach to animal hair, as they are also annoyingly good at sticking to trousers.

Prickly stick insect.
Shutterstock

Many plants pack their seeds in delicious fruit which attracts animals with bright colours and alluring fragrances. When animals eat the fruit, some of the seeds make it through their digestive tract and are deposited far away.

This gives these seeds a better chance at survival, because they are not in competition with the parent plant.

This is a challenge that stick insects also face, as they’re not the most mobile twigs on the bush. Stick insects are slow and only move at night to avoid being seen by predators. Dispersal by birds helps avoid localised competition between generations.

Greenheaded ant carrying an Acacia seed.
James O’Hanlon, Author provided

But this isn’t where the similarities end. Some species of stick insect have eggs that are covered in long prickly spines that may have evolved to stick to animal fur, just like plant seeds.

There is even some evidence that stick insects arrived in Madagascar from somewhere on the other side of the Indian Ocean. This prompts the question of whether their eggs float across the vast seas like miniature coconuts.




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Everyone wins

Stick insects and plants have also developed a mutually beneficial relationship with ants to disperse their eggs and seeds.

In Australia, we have a huge diversity of “myrmecochorous” plants (trees and shrubs whose seeds are picked up and carried by ants). These plants attract ants with “elaiosomes”, which are small structures on their outer surface packed full of nutritious ant food.

Some species stick insects’ eggs also have strange-looking structures on their outer surface. It turns out that these structures, called “capitula”, are also full of nutritious ant food. And sure enough, after the eggs are laid, ants will pick them up and carry them to their nests.

An ant’s nest is a surprisingly safe place for an egg or seed. In there, they are protected from fire, predators, parasites, and drying out.

A green-headed ant inspecting a goliath stick insect egg.
James O’Hanlon, Author provided

(Exactly how the newly hatched stick insects escape from the ant nest is a mystery – for now.)

It appears stick insects may have taken more than just one leaf out plants’ book – they may be more “plant-like” than we had ever imagined.


The Conversation


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James O’Hanlon, Postdoctoral research fellow, University of New England

This article was originally published on The Conversation. Read the original article.

The secret agents protecting our crops and gardens


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Lacewings are fantastic predators and are easy to rear and release.
Dan Papacek & Tony Meredith (Bugs for Bugs), Author provided

Lizzy Lowe, Macquarie University and Manu Saunders, University of New England

Insect pests cause a huge amount of damage to crops globally. In Australia alone, pests are responsible for around A$360 million of crop losses a year. Controlling pest outbreaks is crucial for food security and human health. Since the 1940s, our primary defence against crop pests has been synthetic pesticides. But using pesticides comes at a huge cost.

Not all bugs are bad!

Bees, flies and butterflies help to pollinate our plants. Decomposers like beetles and worms help break down wastes and return nutrients to the soil. Meanwhile, predators and parasites help control the species that are pests. One of the biggest environmental problems with pesticides is that they can affect these beneficial species as well as the pests they’re targeting.

Predatory insects and spiders control pests with none of the health and environmental risks of chemicals. So when we kill these species with insecticides, we are shooting ourselves in the foot.




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Losing insects also has flow-on effects for larger animals that rely on them for food. Because invertebrates have such important roles to play in our environment, losing them to insecticides can completely change how ecosystems function.

An alternative to insecticides

Biological control (or biocontrol) relies on “secret agents” – the natural enemies (predators and parasitoids) of pests that live freely in the ecosystems around us.

There is a huge range of predatory invertebrates that eat pests. They include dragonflies, preying mantids, beetles (including ladybugs), lacewings, spiders, mites, wasps, and even some flies.

Parasitoids, meanwhile, are insects that lay their eggs in the bodies of other invertebrates. Their larvae extract nutrients from the host during their development, which ultimately kills the host. Wasps are best known for this strategy but there are also parasitoid flies and beetles.

Lady birds are voracious predators ready to eat pests in crops and gardens.
Manu Saunders

Predators and parasitoids are useful because they use pest insects, like caterpillars and aphids, as food to reproduce and grow their populations. We walk past many of these hard working agents every day without knowing it.

One biocontrol method that gardeners and land managers use is called augmentation. This simply means raising lots of live individuals of particular natural enemies, like ladybirds or wasps, and releasing them into an area to control pests.

Alternatively, gardeners might change the local environment to encourage these natural enemies to move in on their own. They might include natural insectariums or planting different types of vegetation to encourage diverse invertebrate communities. There is increasing evidence of the success of these strategies in organic farming so we should be thinking about using them more broadly.

Selecting your insects

If you want to release biocontrol agents, you need to choose them carefully, just like human special agents. Like any introduced plant or animal, there is a risk that good bugs could become pests (if they feed on the wrong insects, for example).

Selecting biological control agents requires close collaboration between managers, skilled entomologists and other scientists. For each new species, they identify the pest and some potential predators. They look at the predator’s life cycle and resource needs, and consider how it interacts not just with pests, but with other insects too. If agents are coming in from overseas, they also need to be cleared by government biosecurity.

Parasiotid wasps, lacewings, predatory mites, ladybird beetles, and nematodes are all common biocontrol agents. These species are relatively easy to raise in large numbers and work well when released into the field. Spiders are also a really important predator of many pest insects, but they’re often overlooked in the biocontrol game because they are harder to breed – and for some reason people don’t always like releasing large numbers of spiders.

Many biocontrol agents are enemies of pests in general, preying on aphids, caterpillars and fruit flies alike. It’s important to have generalists around for every day pest control, but sometimes a more targeted approach is needed. This is when specialised predators or parasitoids come in. These are species that only target specific pests like leaf miners, beetles, scale insects or spider mites. This way the target pest can be managed with no risk of the parasitoids accidentally attacking other beneficial invertebrates.

Raising good bugs

It’s very exciting to get live insects in the mail!
Lizzy Lowe

Once a biocontrol agent has been selected, greenhouses or lab facilities start raising a large population. This is an emerging market in Australia, but there are already a number of companies in Australia who specialise in rearing biological control agents.

This is a tricky job because demand for the product is variable and is not easy to predict. Warmer seasons are the peak time for most pests, but problems can arise at any time of the year. In most cases the biocontrol company will maintain breeding colonies throughout the year and will be ready to ramp up production at a moment’s notice when a farmer identifies a pest problem. Each company usually provides 10-20 different biocontrol agents and are always looking for new species that might be useful.




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When it comes to getting the agents to the farmers, the bugs can be shipped as eggs (ready to hatch on arrival), or as live adults ready to disperse and lay their own eggs. The packages are express posted in boxes designed to keep the insects cool and safe.

Once the farmer or natural resource manager receives the bugs, applying them is quite simple. The secret agents are released among the crops, usually by hand, but in some special cases they may be airlifted in via specialised drones!

Drones can be used to deploy biological control agents.
Nathan Roy (Aerobugs)

It’s important to monitor the pests and the biological control agents after release to check that the agents are working. Some farmers are happy to do this themselves but most biological control companies have experts to visit the farms and keep an eye on all parties.

Can I use good bugs in my garden?

The ConversationIf you have a problem with a pest like aphids it is possible to buy predators such as ladybirds or lacewings to quickly deal with the problem. But for long term pest control, there are probably already some natural enemies living in your garden! The easiest and cheapest way to help them is to put the insecticides away and ensure your garden is a friendly environment for secret agents.

Lizzy Lowe, Postdoctoral researcher, Macquarie University and Manu Saunders, Research fellow, University of New England

This article was originally published on The Conversation. Read the original article.