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| Read on to find out why I was excited to see this guy |
At the Narrandera Food Garden we are trying to adopt permaculture principles into our gardening practices. Permaculture is all about working with nature to achieve an end goal that is beneficial for all. This means trying to encourage natural pollinators and pest control agents, rather than poisoning our environment, ourselves, and all those ‘good’ bugs (and the things that eat them!) out there by using pesticides and herbicides.
We live in a very chemical-based society, and it’s so easy to get caught up in thinking that we have to use pesticides and herbicides all the time to get rid of weeds and pests. However, this over-reliance on chemical controls has been proven to result in not only the loss of plants, insects and animals that can help us control the ‘bad guys’ but also to create environments that encourage weed growth and pest attacks (invasive weeds are the first to encroach on bare ground after weed spraying, due to the lack of competition; and loss of predatory insects, due to broad-scale pesticide use, can give the pest species that emerge later free reign). Agricultural scientists are also finding that weed and pest species are developing resistances to commonly-used pesticides and herbicides, making them less effective, and forcing chemical control companies to develop ever more potent poisons. The end result of this cycle is a higher and higher reliance on chemical controls as we steadily remove harmless and beneficial species from our gardens and crops, and more and more chemicals going on and into our food, soil, water and air. The only winners in this cycle are the chemical companies.
However, if we stop and look at nature and history, and think for a bit, it becomes clear that we don’t really need to rely so heavily on chemicals. People had been growing food for centuries before pesticides came into vogue, and nature is nothing if not creatively opportunistic. For every species that exists, there are other species that have evolved alongside them and have adapted to feed on, parasitise, pollinate, or otherwise interact with them. This is how we get pest species that damage our plants, but it’s also how nature has provided us with pest controllers, ready and willing to take out those pesky pests for us, if only we let them. Of the millions of insect species that exist, only a very small percentage actually pose a threat to our gardens and food crops, the others either have no impact or are good to have around – but pesticides don’t differentiate.
A healthy garden is a garden with insects in it; as well as spiders, and mites, and nematodes, and fungi, and birds, and lizards, and frogs, and earthworms, and preferably a few mammals, depending on the type and size of both the garden and the mammals in question (a mob of kangaroos in your veggie bed for instance is probably not something you want; likewise some fungi, mites and nematodes are on the ‘bad guy’ list, whilst others you really want to keep around).
If your garden is completely insect-free, then your garden is sick, even if it looks lovely and lush. You will also find that if your garden is insect-free you will need to work much harder to keep it both insect-free and looking lush – and gardening should be fun, not hard work!
If your garden is completely insect-free, then your garden is sick, even if it looks lovely and lush. You will also find that if your garden is insect-free you will need to work much harder to keep it both insect-free and looking lush – and gardening should be fun, not hard work!
Beneficial Insects
‘Beneficial’ insects, as you might assume from the name, are insects that are beneficial to have in your garden or agricultural crop. They pollinate your plants and control your pests, completely for free and with no effort required on your part – win/win!
Pollinators
When you think of pollinating insects, you probably think of bees, but butterflies, moths, beetles and even some species of flies can all be important pollinators as well. For example, hands up if you’ve got hoverflies at your place?
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| Hoverfly picture from Wikimedia Commons |
Hoverflies are small (8-20mm) flying insects with black and yellow stripes, that look kind of like tiny bees or wasps (but they don’t sting), and can often be found hovering in a cloud over flowering plants, especially during the warmer months. They are a type of fly, and they’re great to have in your garden because the adults pollinate flowers and the larvae eat aphids.
Predatory beneficial insects
Pest-controlling insects come in two categories – predators and parasites. Predatory species actively hunt down and eat other insects, and include various kinds of beetles, including most species of ladybeetles, some shield bugs, all spiders (not technically insects, I know, but bear with me), lacewings, some species of wasps, and many others. For some species the adults are the predators, for others (like ladybeetles and lacewings) it’s the larvae, and in some cases it’s both.
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| Slide-shot from beneficial insects workshop run by Phil Bowden |
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| Ladybird larva pic from http://www.brisbaneinsects.com/ |
Brisbane Insects have a great pictorial field guide for recognising the adults and larvae of several different species of ladybeetles. The larval forms look nothing like adult ladybeetles, so it's a good idea to familiarise yourself with what they look like, in case you see one in person and think it's a pest instead of a good guy.
CSIRO have also got a good website all about Australian ladybeetles.
Parasitic beneficial insects
Parasitic species generally lay their eggs inside the bodies of their hosts and the emerging larvae eat the host as they develop – thus proving that even the most terrifying alien horror movies can’t hold a candle to the things nature has thought up. A lot of wasp species are parasitic, including some microscopically tiny wasps that parasitise aphids. So if you see some mummified aphids on your veggies, you know you’ve got tiny wasp buddies helping you out.
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| Slide-shot from beneficial insects workshop run by Phil Bowden |
What's up in our Food Garden?
After attending the workshop I was curious to see what beneficial insects were helping us out up at the Food Garden, so I headed up there with my camera to see what might be seen.
When setting up the gardens we made sure to include lots of flowering species, including some that are generally considered to be purely decorative, and there are lots of lavender, salvia, and alyssum flowers in bloom at the moment, along with flowers on the eggplant and tomato plants. When we planted them, some people asked why we were planting non-food species in our food garden, and the answer was very well illustrated the other day – there were dozens of bees and several butterflies busily flying around and investigating our different flowers, and pollinating them for us. More flowers means more chance of attracting pollinators, who will happily visit the food species as well as the non-food ones. Below are pics of bees in several of the beds and some of the visitors I found amongst the alyssum in Angela’s plot (click on the pictures to view them larger).
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| Butterfly |
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| Bee |
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| Bee |
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| Fly - possibly a small hoverfly? |
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| Hoverfly |
As expected, I saw a lot of ‘normal’ bees (European honey bees, a common sight in many gardens) and then my attention was caught by a loud frantic buzzing, reminiscent of a blowfly, and a flash of shiny blue. This led to my delighted discovery that the eggplants in the Duncans’ plot are being pollinated by native blue banded bees. I watched for a while and got to see for myself the interesting way that blue banded bees ‘buzz-pollinate’ flowers.
The Blue Banded Bee website describes buzz-pollinating thus:
Most flowers release their pollen passively, but others like the tomato flower only release their pollen when the flower is vibrated rapidly – ‘buzz-pollination’. Bees capable of buzz-pollinating clamp their legs onto the anther cone of the flower and contract their flight muscles so vigorously that the pollen is released.
This happens really quickly, so from the point of view of myself watching, the bee would enter the flower, buzz rapidly for a second or two and then leave and head to another flower. This is what caused the very loud buzzing I could hear, which was what led me to look for and find the bees in the first place. My eyes were a bit quicker than my camera, so I could see the shiny blue stripes across the bees’ abdomens very clearly, but they’re fast little things and it was difficult to get any photos. Here are my best shots:
They’re fun to watch, and it’s a bit exciting to know that we have some native bees in the garden, so keep an eye out for them the next time you head up. Have a look for them in your gardens at home too, because if they’re in the community garden, they’ve got to be elsewhere around town as well.
You might also like to check out this lovely chart by Hunter Local Land Services that shows several species of native Australian bees - some of which we get around here (although we're a long way from the Hunter region):
In Miriam’s plot I found a couple of caterpillars (not so good, but they’ll grow up to be butterflies or moths one day, and be helpful pollinators then), as well as some rather pretty shield bugs. I thought they were different species at first, but some poking around on the internet informed me that I was looking at adults, third instar nymphs, and fifth instar nymphs of the same species - probably recognisable to many of you as green potato bugs. They’re a sap-sucking species but generally considered to be harmless and unlikely to ravage your garden plants.
[Vocabulary time: nymphs are the immature forms of insects, they undergo a series of physical changes/metamorphoses before reaching adulthood/sexual maturity. The stages are referred to instars.]
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| Caterpillar with adult and 3rd instar nymph shield bugs |
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| 5th instar nymph shield bug |
While walking around the gardens I kept seeing one or two flying insects that looked like a brown inverted ‘L’ as they drifted around. Finally one landed and I managed to get a couple of photos. Some more searching on the internet, because I’m not good at insect ID, has led me to the conclusion that this is some sort of parasitic wasp. So those caterpillars might be in trouble!
I also found two different species of ladybeetles - a good guy and bad guy:
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| 'Bad guy' - leaf-eating 28-spotted ladybird |
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| 'Good guy' - aphid-eating spotted amber ladybird |
In the shed were a few spiders, and there are always birds of various species hanging around the gardens, thus making up our complement of insectivorous predators, helping to keep our garden healthy and our pest numbers low.
It was really fun discovering the different insects at home in the Food Garden, and I highly recommend taking an insect safari around your own gardens and backyards to see what you can see. You might be surprised and delighted by what you find.
Some more links you may want to check out:
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