The weather is getting warmer, and gardens are coming alive with bees, flies, butterflies, dragonflies, praying mantises, beetles, millipedes, centipedes, and spiders.
For some of us it is exciting to see these strange and wonderful creatures return. For others, it’s a sign to contact the local pest control company or go to the supermarket to stock up on sprays.
But while some bugs do us very few favours – like mozzies, snails and cockroaches – killing all insects and bugs isn’t always necessary or effective. It can also damage ecosystems and our own health.
Read more: The hidden secrets of insect poop
There are times when insecticides are needed (especially when pest populations are surging or the risk of disease is high) but you don’t have to reach for the spray every time. Here are five good reasons to avoid pesticides wherever possible, and live and let live.
1. Encourage the bees and butterflies, enjoy more fruits and flowers
Flowers and fruits are the focal points of even the smallest gardens, and many of our favourites rely on visits from insect pollinators. We all know about the benefits of European honey bees (Apis mellifera), but how about our “home grown” pollinators – our native bees, hover flies, beetles, moths and butterflies. All these species contribute to the pollination of our native plants and fruits and veggies.
You can encourage these helpful pollinators by growing plants that flower at different times of the year (especially natives) and looking into sugar-water feeders or insect hotels.
2. Delight your decomposers, they’re like mini bulldozers
To break down leaf litter and other organic waste you need decomposers. Worms, beetles and slaters will munch through decaying vegetation, releasing nutrients into the soil that can be used by plants.
The problem is that urban soils are frequently disturbed and can contain high levels of heavy metals that affects decomposer communities. If there are fewer “bugs” in the soil, decomposition is slower – so we need to conserve our underground allies.
You can help them out with compost heaps and worm farms that can be dug into the ground. It’s also good to keep some areas of your lawn un-mowed, and to create areas of leaf litter. Keeping your garden well-watered will also help your underground ecosystems, but be mindful of water restrictions and encouraging mosquitoes.
3. An army of beneficial bugs can eat your pests
Mantises and dragonflies are just some of the hundreds of fascinating and beautiful bugs we are lucky to see around our homes. Many of these wonderful creatures are predators of mozzies, house flies and cockroaches, yet people are using broad-spectrum insecticides which kill these beneficial bugs alongside the pests.
It may sound counterproductive to stop using pesticides in order to control pests around the home, but that’s exactly what organic farmers do. By reducing pesticides you allow populations of natural enemies to thrive.
Many farmers grow specific plants to encourage beneficial insects, which has been shown to reduce the damage to their crops.
This form of pest control in growing in popularity because spraying can result in insecticide resistance. Fortunately, it’s easy to encourage these bugs: they go where their prey is. If you have a good range of insects in your yard, these helpful predators are probably also present.
4. Your garden will support more wildlife, both big and small
Spraying with broad-spectrum pesticides will kill off more than just insects and spiders – you’re also going after the animals that eat them. The more insects are around, the more birds, mammals, reptiles and frogs will thrive in your backyard.
Baiting for snails, for example, will deter the blue-tongue lizards that eat them, so cage your vegetables to protect them instead. Keeping your garden well-watered, and including waterbaths, will also encourage a balanced ecosystem (but change the waterbaths regularly).
5. You and your family be happier and healthier
Engaging with nature increases well-being and stimulates learning in children. Insects are a fantastic way to engage with nature, and where better to do this than in your own back yard! Observing and experimenting on insects is a wonderful teaching tool for everything from life cycles to the scientific method. It will also teach your kids to value nature and live sustainably.
It’s also a hard truth that domestic pesticides present a significant risk of poisoning, especially for small children.
In reality, the risk of exposing your children to the pesticides far outweighs the nuisance of having a few bugs around. Instead, integrated pest management, which combines non-chemical techniques like cleaning of food residues, removal of potential nutrients, and sealing cracks and crevices, is safer for your family and your garden ecosystems.
Think globally, act locally
Your backyard has a surprising impact on the broader health of your neighbourhood, and gardens can make significant contributions to local biodiversity. Insects are an important part of ecosystem conservation, and encouraging them will improve the health of your local environment (and probably your health and well-being too).
In the end, insects and spiders are not out to get you. For the sake of our kids and our environment, you should give them a chance.
Lizzy Lowe, Postdoctoral researcher, Macquarie University; Cameron Webb, Clinical Lecturer and Principal Hospital Scientist, University of Sydney, and Kate Umbers, Lecturer in Zoology, Western Sydney University
I recently wrote about how important it is to be able to identify plants and animals. Knowing the names of species that live around us helps us to connect to nature.
Yes, you can enjoy greenery and birdsong without knowing which species are involved, but recognising the call of a magpie while walking under a lemon-scented gum can enrich your experience. It makes nature more personal and accessible.
The most diverse and common group of animals in your neighbourhood (and mine) are the insects. Children are often drawn to these mini-beasts and are too often warned away by well-meaning adults who are afraid they might get stung.
The fact is that knowing your insects is a gateway to developing a relationship with the natural world. Who has not marvelled at a trail of ants carrying crumbs, enjoyed the sound of cicadas on a hot summer day, or watched bees pollinate flowers?
Insects are found everywhere and are incredibly diverse. They are critical to the health of any ecosystem, including your backyard or garden. Knowing enough to tell the main groups apart is a great way to learn about animals.
Insect swarm at my place
We had an interesting experience in our garden last week. Several wattle birds were swooping overhead and then half a dozen magpies arrived and started pecking at the grass at our feet. This was unusual behaviour so we watched closely and eventually noticed a swarm of insects above the vegetable patch.
There were both small and large insects in the swarm and I guessed that the large ones were predators, enjoying the feast along with the birds, but I was wrong. After finding the sweep net and collecting a few we realised that we were looking at a termite mating swarm. The larger insects were the females, and every now and then pairs dropped to the grass to do the deed.
Many people when they hear this story will cringe at the implications of having termites near the house, but most termite species do not eat wood and are not a danger to infrastructure. We placed a few dozen into a mesh enclosure along with some water, newspaper, wood and a jar of soil. The next day they had all burrowed into the soil, so we think they hatched out of our garden compost.
How did I know they were termites? Because termites belong to the order Isoptera, which literally means “same wings”. Unlike most insects, their four wings are all the same size and shape. Once you know this it is easy to distinguish between them and winged ants (who have four wings of different sizes) or flies (who have only two wings). A little bit of knowledge is a powerful thing.
Learning more about bugs
How will you learn to identify insects? A new book called Miniature Lives: identifying insects in your home and garden, by Michelle Gleeson would be a good start. It was mentioned on the CSIRO blog just a few days ago.
If you look around, you may find activities like Bring Ya Bug Along, which will be run by a friend of mine in our home town in a few weeks.
Of course, not every bug will be a bug. This sounds odd but there is an order of insects known as “true bugs” (Hemiptera). They have sucking mouthparts which they use to pierce plants or prey. So even the word “bug” has some linguistic problems and how you use it depends on who you are talking to.
Beetles are the most common insect order (Coleoptera), and most people can recognise them from the hard wing covers. Probably the most popular insect order is the Lepidoptera (moths and butterflies). Yes, they are beautiful but their caterpillars can be bad for the garden.
Lacewings (order Neuroptera) are also beautiful in their adult form. As juveniles they are called ant-lions, which are fearsome little predators that eat garden pests. You can even buy lacewings eggs from Bunnings to add to the garden.
I could go on but if I have sparked your interest, just buy a book or go online to start learning. Using insects as a gateway to connect with nature is something everyone can do.
The prize for the most painful and sometimes deadly (more on that later) stings in the insect kingdom goes to … wasps, bees and ants.
There are many insects that bite, such as beetles and dragonflies, or suck your blood with long hypodermic mouthparts (mosquitoes, for instance, and sandflies). But none of these are deadly in themselves.
Mosquitoes do transmit deadly diseases, such as malaria and dengue. But it’s not the mosquito bite as such that kills; it’s the tiny parasitic microorganism that the mosquito transmits.
It’s really bees, wasps and ants – a group known as Hymenoptera – that can claim the title of deadliest insects. How did they evolve to be so painful?
How insects stings evolved
Many wasps are parasitic and developed long pointy hypodermic needles (or ovipositors) to inject their eggs into their hosts. Over evolutionary time, some of these parasitic wasps changed their lifestyle and became predatory. Some even went on to feed on pollen and nectar (bees).
What happened to the ovipositor when wasps no longer needed to inject eggs? It became a pointy sting, a device for subduing prey with venom, as well as laying eggs.
It’s important to remember that only female wasps, bees and ants can sting; males don’t have the right apparatus.
Many of these stinging wasps, bees and ants have also become highly social insects. This means they live in large colonies such as honeybee hives, or ant nests. In these colonies, generally only a pair (a queen and a male drone, in the case of honeybees) or a few individuals reproduce.
All the rest are genetically and anatomically sterile females, and they do all the work inside and outside the hive or nest. These workers no longer need an ovipositor to lay eggs and it has become their primary weapon of choice, solely devoted to defence of the nest.
Workers use the sting to defend the wasp or bee nest, or ant colony. Queen bees lay eggs with their ovipositor and can also sting, but are usually tucked away in the nest far from harm.
Worker bees can sting humans only once – their barbed sting lodges in our skin and doesn’t retract, so the entire sting and the poison gland breaks free from the bee when it stings. The worker bee dies soon after and releases alarm pheromone, which alerts other workers that the nest is under threat.
More bees sting and release more alarm pheromones, attracting more alarmed bees … you get the picture. If you’re stung, remove the sting as soon as possible – this minimises the amount of venom injected.
A very small number of people (about one or two in every 100) can become hypersensitive after a bee sting. They become allergic to the venom, and their reaction becomes stronger when stung in future.
A highly allergic person may suffer anaphylactic shock from the sting, which can be life-threatening and requires medical treatment. A self-injecting EpiPen containing adrenalin is used to treat anaphylactic shock.
The most painful
Another common introduced stinger in Australia is the European wasp, Vespula germanica. This wasp’s sting doesn’t get stuck in our skin, so they can inflict multiple stings when annoyed or provoked. A very good way of provoking a large number of European (or any other) wasps is to disturb their nest – never do this.
A very small percentage of people can also develop an allergic reaction to European wasp stings, just like honeybee stings. In severe cases, this can cause anaphylactic shock.
Arizona entomologist Justin O. Schmidt developed the Schmidt Pain Index 30 years ago to rank the painfulness of wasp, bee and ant stings on a four-point scale.
Zero on the Schmidt pain index is the feeling of an insect that can’t sting you, such as Australia’s native stingless bees. Two is the familiar pain of a honeybee. Four is reserved for just a few heavy hitters, such as a very large spider-killing wasp, or the infamous bullet ant (Paraponera clavata) of South America.
The notorious and excruciating pain of the bullet ant lasts for 24 hours. Schmidt has been stung by more than 100 insects to create his scale, and was awarded the 2015 Ig Nobel Biology Prize for his efforts.
Some of the most common painful stingers in the Australian bush are native bulldog ants of the genus Myrmecia. These are some of the largest ants in the world and combine a painful sting with an aggressive, take-no-prisoners attitude. On top of this, many species can jump. They rate up to three on the Schmidt Pain Index.
Bulldog or jack-jumper ants have impressive long, toothed and curved jaws, but it’s the sting at the end of their abdomen that does the damage.
My most painful memory as a boy was annoying a bulldog ant nest in the Sydney bushland with a stick. Eventually a huge worker bulldog ant crawled up out of sight underneath my stick and gave me a sting on the thumb I thoroughly deserved – and will never forget.
Over the past 40 years (but in reality since I was five years old), I’ve been fascinated with insects and their ability to sting and cause pain. In graduate school, I became interested in why they sting and why stings from such tiny animals hurt so much.
To answer these questions, we first needed a way to measure pain – so, I invented the insect pain scale. The scale is based on a thousand or so personal stings from over 80 insect groups, plus ratings by various colleagues.
Insects sting to improve their lives and increase their opportunities. The stings provide protection, thereby opening doors to more food resources, expanded territories, and social life within colonies. By studying stinging insects, we gain insight into our own lives and the societies we live in.
To say that insects sting “because they can” isn’t all that helpful. The real question is why insects evolved a stinger in the first place. Obviously, it had some value, otherwise it would have never evolved – or, if initially present, it would have been lost through natural selection.
Stingers have two major uses: to get food and to avoid becoming food for some other animal. Examples of the stinger used for sustenance include parasitic wasps that sting and paralyse caterpillars that become food for the wasp young, and bulldog ants that sting difficult prey insects to subdue them.
More importantly, the stinger is a major breakthrough in defence against large predators. Imagine, for a moment, that you’re an average-sized insect being attacked by a predator a million times larger than you. What chance would you have?
Honeybees face this problem with honey-loving bears. Biting, scratching or kicking won’t work. But a stinger with painful venom often does.
In this sense, the stinging insect has found a way to overcome its small size. The stinger is an “insect gun” of sorts – it neutralises the size difference between assailant and victim.
The insect sting pain index
This is where the insect sting pain index comes in. Unless we have numbers to compare and analyse, sting observations are just anecdotes and stories. With numbers, we can compare the effectiveness of one stinging insect’s painful defence against others and test hypotheses.
One hypothesis is that painful stings provide a way for small insects to defend themselves and their young against large mammalian, bird, reptile or amphibian predators. The greater the pain, the better the defence.
Greater defence allows insects to form groups and become complex societies as we see in ants and social wasps and bees. The greater the pain, the larger the society can become. And larger societies have advantages not enjoyed by solitary individuals or smaller societies.
Human and insect societies
Human sociality allows individuals to specialise and do a particular task better than most others. Examples of human specialists include plumbers, chefs, doctors, farmers, teachers, lawyers, soldiers, rugby players and even politicians (a profession sometimes viewed dubiously, but required for society to function).
Social insect societies also have specialists. They forage for food, tend to young, defend the colony, reproduce and even serve as undertakers removing the dead. Another advantage of societies is the ability to recruit others to exploit a large food source, or for the common defence, or to have additional helpers for difficult tasks.
Sociality also has a more subtle advantage: it reduces conflict between individuals within a species. Individuals not living in social groups tend to fight when they come in contact. But to live in a group, conflict must be reduced.
In many social animals, conflict is reduced by establishing a pecking order. Often, if the dominant individual in the pecking order is removed, violent battles erupt.
In human societies, conflict is also reduced via pecking order, but more importantly through laws, police to enforce laws, and gossip and societal teachings to instil co-operative behaviour. In insect societies, conflict is reduced by establishing pecking orders and pheromones, chemical odours that identify individuals and their place in society.
Why do we love pain?
The insect sting pain index also provides a window into human psychology and emotion. Put simply: humans are fascinated by stinging insects. We delight in telling stories of being stung, harrowing near-misses, or even our fear of stinging insects.
Why? Because we have a genetically innate fear of animals that attack us, be they leopards, bears, snakes, spiders or stinging insects.
People lacking such fear stand a greater chance of being eaten or dying of envenomation and not passing on their genetic lineage than those who are more fearful.
Stinging insects cause us fear because they produce pain. And pain is our body’s way of telling us that bodily damage is occurring, has occurred, or is about to occur. Damage is bad and harms our lives and ability to reproduce.
In other words, our emotional fear and infatuation with painful stinging insects enhances our long-term survival. Yet, we have little emotional fear of cigarettes or sugary, fatty foods, both of which kill many more people than painfully stinging insects. Fear of those killers is not in our genes.
The insect sting pain index is more than just fun (which it is too). It provides a window into understanding ourselves, how we evolved to where we are, and what we might expect in the future.