Little Critters, Big Helpers!

Photo: J Green, CSIRO Entomology
We couldn’t survive without the help of our hardworking friends

Let’s play a word association game. Ready…..What is the first word or emotion that comes to you when I say “insect”? What did you think of? Did you feel a sense of wonder, fascination or curiosity? Or did you feel a bit icky, or maybe even scared or repulsed?

If you felt the latter, you are not alone. And such a response is understandable considering that certain insects can be damaging to humans; some of the most devastating diseases in the world are transmitted by mosquitoes, insect pests can decimate crops, and termites can chew through our houses. BUT, did you know that of over a million described species of insects, only a tiny proportion are considered to be serious pests. The vast majority of species are either totally harmless, or are beneficial. In fact, without insects, our own survival would become rather precarious. We need these little critters to survive!

Insects are involved in many important processes in ecosystems, like pollination, nutrient cycling and decomposition. We can call these processes ecosystem functions. If these ecosystem functions benefit humans, these functions can be considered as ecosystem services. Insects can either influence or directly provide many ecosystem services such as pollination, seed dispersal, nutrient recycling, biological control of other pest insects, decomposition, soil formation, soil aeration….the list goes on! And it is easy to understand how these ecosystem services are useful to humans: pollinators move pollen from one flower to another, allowing plants to reproduce and produce fruit for us to eat, parasitoid wasps can reduce the number of caterpillars eating our crops, and dung beetles recycle nutrients thereby improving pasture health and farm productivity. For some insect groups however, the distinction between a beneficial insect and a detrimental one can be a grey area, and can challenge us to make something of a cost-benefit analysis. Are the occasional stings that we receive from ants balanced by the provision of ecosystem services such as soil aeration and bioturbation (the mixing of soil), seed dispersal and waste removal? Even though termites can eat our houses, is this cost compensated for by the important role they play in nutrient recycling,  decomposition of cellulose-rich material such as fallen trees, and the provision of food for echidnas, numbats, lizards, snakes and birds?

Insects and the ecosystem services that they provide are critical to human life. In his famous 1987 paper, “The little things that run the world”, ant ecologist Edward O. Wilson predicted that human life would not persist beyond a few months if all of the invertebrates (of which insects belong) were to disappear from the planet (Wilson, 1987). Estimates of the dollar value of insect ecosystem services are well into the billions of dollars, making them a valuable asset both ecologically and financially.

A recent review of the decline of insects across the globe has found dramatic rates of species declines, driven by factors such as habitat loss and conversion to intensive agriculture, urbanisation, pollution by pesticides and fertilisers, pathogens, and climate change. To address these declines, and to preserve vital insect mediated ecosystem services, we need to rethink current agricultural practices, reduce pesticide use, and use more sustainable and ecologically based practices (Sanchez-Bayo and Wyckhuys 2019). And of course, tackling the challenge of climate change will bring many benefits, not just to the insects!

It all seems a bit overwhelming doesn’t it? You may be asking yourself “what can I do?” The good news is that there is a lot you can do, just in your own backyard. The following is not an exhaustive list, just some ideas to get you started harnessing the benefits of insects (and other invertebrates) at your place. First, reduce pesticide use around the house and garden. To remove an insect or spider from the house, carefully relocate it outside using a container. If you absolutely have to, a sharp smack with a shoe is a more environmentally way of disposing of an unwanted invertebrate rather than spraying it with pesticides. In the garden, instead of pesticides, use predator insects, such as lady birds, to control aphids, mites and scale insects. To encourage beneficial insects like pollinators and predators into your garden, grow a variety of flowering plants to supply nectar and pollen to them, and make insect hotels to provide habitat. I usually let some of my vegetables, like lettuce, go to flower in our garden to provide a supplemental food source for insects. Although they are not insects, I am also super excited to be starting my first worm farm very soon to supply organic fertiliser for our garden!

One of the biggest steps that can be taken to preserve insect mediated ecosystem services is simply realising how important insects are, and perhaps shifting our attitudes towards these marvellous little creatures. Although some insects can be detrimental to us, they only account for a very small proportion of insects on the planet. The vast majority of species are either harmless, or beneficial. Furthermore, as we have discovered above, the distinction between a ‘good’ or ‘bad’ insect can be blurry. Before you hurry to squish or spray an insect, think about the potential benefits in may be providing. Perhaps let the insect go on its merry way, and thank it for all that it will do for us and the planet.

Image: CSIRO

These are the papers referenced above:

Wilson, E.O. 1987. The Little Things That Run the World (The Importance and Conservation of Invertebrates). Conservation Biology. 1:344-346.

Sanchez-Bayo, F., Wyckhuys, K. A. G. 2019. Worldwide decline of the entomofanuna: A review of its drivers. Biological Conservation. 232:8-27.

– By Dr Jean Holley, UNE Voyager member, insect ecologist and dung beetle enthusiast